U. S. Departrtler~t of Agriculture 

erleral Technicn Report S E- 14 

PROCEED NGS o the Workshop 

Management o Southern Forests 

5. Department of Ay 

L ~ou theas t~rn Forest 

Nangame Birds 

Januaa-y 24-26, 1978 

anta, Georgia 

ricultuve - Forest Seroiee 

Experiment Station 

Sponsors: Offices of the Forest seervice. L,S. Department of AgrieuIture, in Sou&-- 

the Southern Region: the Southeast~rn State and Priv-,te Foreshy :he 

Southcastern Forest E:.:periment Slation ; and $he Southern Fore& Experiment 

Station. 
Sou~keei; term Forest Experi:aentSSta tion 

.c~~s'nevilLe, C;crrh Carciina 

The skc tch, dra:.in by Dr, Sidney A, Cauthreaux, D~partnent of Zoology, Clemssn Cniversi ty , s5o\.:s the Srown-headed nuthatch; which inhabits souti-:ern pinelands, 

-- ~hj.s Prececdings xas phoragraphsd from cagy subxittcd by the contributors, Thc Scutkzastern 

Forest Zxperiaent Staticn ~GCS not SSSUE~ responsibility Lor any errors contained herein, 
Proceedings of the 

Wbrkshop Hanagement of Southern 

Forests for Nongame Birds 

January 24-26, 1978 

Atlanta, Georgia 

Technical Coordinator: 

Richard M, DeGraaf 

Research Wildlife Biologist, 

Northeastern Forest Experiment Station 

Chairman, National Nongame 

Bird Steering Cornittee 

U,S. Department of Agriculture --- Forest Service 

Southeas tern Forest Experiment Station 

Asheville, North Carolina 
PREFACE 

In Hay, 1975, a symposiam was conducted in series, and presents bird habitat research 

Tucsan, Arizona,on the management of foresr. and results and panagemen% techniques fan. all major 

range habitats for nongame birds. That landmark habitat types in the southern and southeastern 

~eeting opened a dialog between avian ecologists United States. This workshop is jointly hosted 

and resource managers. It was widely agreed that by the USDA-Forest Service--the Southern Region; 

birth groups benefitted each other, and that a Southeastern Area, State an3 Private Forestry; 

scrics of regional workshops should be held, Southeastern Forest Cxperi~ent Station; and the 

The objective of the series would be to insure Southern Forest Experiment Station, 

that. rmngame bird habitat requirements are con- The Forest Service was joined by the 

bidered in significant land management practices, National Nongame Bird Steering Committee in 

and that a diversity of natural biological sponsoring this workshop. Its members include: 

cornunities are maintained. 

To that end, the National Nongame Bird Forest Service, USM 

Sreering Committee was formed to sponsor regional Sail Conservation Service, USDA 

workshops to present the state of the art of non- Fish and Wildlife Service, USDl 

game bird research and management in various eco- Bureau of Land Management, USDL 

regions of the United States, The first workshop National Wildlife Federation 

in the series was held in Portland, Oregon, Feb- The ldildlif e Society 

ruary 7-gp 1977, entitled, "Nongame Bird Habitat Wildlife Management Institute 

Management in the Coniferous Forests of the National Audubon Society 

Western United States". international Association of Wildlife 

'I'hjs workshop, "Man,%gement of Southern Conservation Agencies 

Forests for Nongame Bfrds", is the second in the 
Kevnote Address: ,"fa~agemnt of nongame .;~ildlifc--a need rrhose time 

hascone ............... me 2 

:zfiehaeZ: 3. Zagatia 

'fie relationship of nongame birds to southern forest tvpes a?d 

successional stages. . . . . . . . . . . . . . . . . . . . . . . . . 5 

2. 11. SS;zugart, T. 14. Smith, J, T* Xitcj2inljs9 and H. L. X~ocdzmcc 

Tile organization of forest avian communities . . . . . . . , . . . . . . . . . . . . . 17 

Sidney Gau kzre aux 

EFFECTS OF ;InPIACE;EfF,;JT PRACTICES OX NO3CiZI.E 'SIf3S . . . . . . . . . . . . . . . . . . . . 

Lan~leaf-slash pine forest bird communities. . . . . . . . . . . . . . . . . . . . . . 40 

&ns i.4, iiiood add Lam2 'Ji Zds 

Bird communities associated with succession and maslagerrrent of 

Poblollv-shortleaf nine forests. . . . . . . . . . . . . . . . . . . 50 

Jose;;la ,:!, !&yers and A. qjdnc7g JO,'~YZSO~Z 

Forest bird csmunlties of tile bottomlad hardwoods. . . . . . . . . . . . . . . . . . 66 

oTcrpnes C, I2ickso-n 

C)alc--pine and oak-Ilf ckorv forest bird camunities and management options. . . . . . . 36 

.KeziC;iZ 0. Eums 

Cove forests and bird comnities. . . . . . . . . . . . . . . . . . . . . . . . . . . 90 

;?obsr-h; G, riooper 

'4 comnarison of avfan comunitxr structure in the ;lorthemP and Sou6'2em 

Ap~alachimIlsuntairas, . . . . . . . . . . . . . . . . . . . . . . . 98 

Sarq I?, ,ioo!.z and Kenrtctii P, Ab Ze 

SPECIALIZED GIRD iliV3IThTS M4D l~Za,UACEPE;dT . . . . . . . . . . . . . . . . . . . . . . . . 219 

Snag mcnsragcmntr for cavity nesting birds . . . . . . . . . . . . . . . . . . . . . . . 120 

iiicr2ard :J, Connez? 

tr'sdinp, birds and wetPands manar;remnt . . . . . . . . . . . . . . . . . . . . . . . . 135 

,fap?j @* Landin 

Census techniques for forest birds . . . . . . . . . . . . . . . . * . . . . . . . . 142 

ChmdZer S, i?olibins 

A rearesentative sample of sngolng and planer? reongame bird research in 

the Soutiteastern Ilegion United States, . . . . . . . . . . . . . . . 165 

Robert 15. Curtis, JP, 

Tuesdav llorning, January 24 

Forest Ecosystem Structure and Function 

and Effects on Birdlife 

Ffoderator: Fred Kinard 

Westvaco Corporation 
Keynote Address : 

Management of Mangame Wildiife--.A Need Whose Tihe Has Come1 

Aldo Leopold and other early workers in 

the profession of wildlife management recognized the theoretical value of considering 

whole communities when making management decisions by coining the often used adage: '%s 

the community goes, so goes the species." 

However, in practive the needs of game species have generally been the only needs considered or have taken priority. Grange 

(1943) outlined the wildlife species associated with various successional stages for a 

white pine climax in Wisconsin. The knowledge that the habitat for great-horned owls 

would be last by setting back succession to 

benefit prairie chickens had little consequence. 

Are we, as professional managers,to be 

faulted for this? Some say yes and some say 

no. Those who say yes feel that wildlife 

mnagement should cons5st of the application 

of ecological principles that perpetuate a 

desired diversity, They recognize that wildlife in general has ecological, economic, 

educational,esthetic, historical, recreational and scientific value to the Nation and 

its citizens, They feel that emphasis on 

game species has preempted a consideration of 

mnagement programs for the nonhunted species. 

Those who say no look to the sources of 

funding for our nation's wildlife management 

programs,and point out that it is the hunter 

who has paid the bill, In addition, they 

stress that game management also indirectly 

benefits some nongarne wildlife. 

At this point the meaningful discussions begin to take place with the recognition that any mnagement action benefits some 

species and adversely impcts others, The 

formerly familiar blanket statement that 

'"gsod forest management is good wildlife management" illustrates the folly sf a simplistic, single species approach to wildlife 

management in today" s~rrL. \*:e now recognize the importance of treating wildlife 

and other resources as part of an interrelated system, 

It is because of the public's 

increased knowledge of these interrelationships that we have been prodded into 

giving greater emphasis to the nongame 

species. The habitat manipulations we 

have made for the benefit of game species 

affected other species directly or indirectly, positively or negatively, 

Because different wildlife species are of 

value to different groups in our society, 

concentration on one species to the detriment of others is Likely to, and in fact 

has,alienate those wl-iose interests have 

been ignored or negatively impacted. 

Because of a greater recognition of 

the value of all wildlife to mankind by 

the wildlife professionals and the 

public, specific legislation to benefit 

nongame wiidiife has been enacted, Examples include the Endangered Species Act, 

the Marine Mamals Protection Act, and the 

Wild and Free Roaming Horses and Burros 

Act* They suffer the same narrow focus as 

our earlier game programs and are defensive actions, They do, however, serve to 

point out two important factors: (I) the 

public is concerned about wildlife for 

wildlife's sake; and (2) the public can 

limit the professional\ ability to employ 

sound ecological principles to manage a 

species, e.g., Kild and Free Roaming 

Horses and Burros Act. In addition, the 

Endangered Species Act and Xarine Efiamal 

Protection Act have illuminated our Lack of 

basic knowledge about the ecological 

requirements of most listed species. 

The reluctance of the professional to 

act on behalf of the public has prompted 

concerned, well-intentioned citizens to 

draft Legislation that would mandate eer- 

%sin actions on behalf of wildlife. On the 

&/lXeynote address at the Workshop on surface this sounds good to those of us who 

Noagame Birds in Southern Forests, Atlanta, have fought the upward battle to gain recog- Georgia, January 24-26, 8978. ,, r nition for the value of game, as well as 

Li~irector of Federal Relations, nongame, wildlife, However, there is a 

National dudubon Society, 2511 K Street, K.W., real danger in this as was evidenced in a 

Mashington, D, C. 20905. 1976 Senate bill entitled "'The National 
Forest Timber Management Reform Act of 1976'' 

(S. 2926). The bill contained many "carrots" 

for those concerned with wildlife but could 

have tied the hands of ehe professional to 

exercise his skills. 

The factors I have alluded to have set 

the sta;.,e for the title of this talk: 

""indgement oi Songame Wildlife - A Reed 

Whose Time Has Come," in 3 1972 survey of 

hotrseilolds in the suirtheasttrn IJnitc~d States, 

rrcinconsur?~ptive vnlucs of i-i sh and wildlif e 

were found to be greater ($12.3 billion) 

than combined fishing and hunting values 

ISll.8 billion). Rc~sults of n 2 975 survey by 

the U.S. Fish and Wildlife Service encornp~.issing all 50 states indicated that one-half ot 

those persons 9 years of age and older who 

participated in nonconsumptive iish and 

wildlife-relaced activities also hunted, 

fished or did both. Membership in the 

National hudubon Society has grown from 

41,000 .in 1963 to over 400,000 today. In 

1976, Missouri voters passed a referendum 

for a constitutional arnendnlent to add a oneeighth of one percent sales tax for conservation that is expected to generate about 

$26 million in 1978 alone, Citizens in 

Fiashington, Colorado and New York ltnve also 

gone on record in support of nongame programs that would include some or ,ill of the 

following: (1) preserve vulnerable qpecies; 

(2) establish wildlife obsdrvation areas; 

(3) inventory wildlife; (4) provide for management; (5) develop wildlife educdtf on material. 

What 1 am saying is that there is a 

very solid base of support for nongame mankgemerzt and that the profiissiondl community 

should take the lead and not have to be 

pushed into converting chat support into a 

program for the management of wildlife by 

considering w'izole coim~unities . The message 

is clear; if we don' t, it will happen in 

spite of us. As professionals, we can not 

allow that to happen. 

Because of the wave of public interest 

in wildlife, Congress tias provided the mandate, or as 1 view it the opportunity, to 

make major strides in our knowledge of wildlife, game and nongarnc 37 ike. The Forest 

and Rangeland Rrnrwable Resources Planning 

Act of 1974 iRISrl), The National Etlr~st Manageineat Act ot 1976, and the L~nd and Water 

Resources Act of 1977 afford us great opportunity to a5scss our fihh and wildlife 

resource, Scrcli an asshl-ssmei~t, conibinect kith 

greater k~~owiedge of i.o:;i;nurlity .~ssoei~~tions, 

will permit us to base managemene decisions 

on sound data and expand our knowledge of 

the impae ts to be expected f rom man-induced 

or natural environmental ~ertubstions, 

Those of you familiar with the RPA process 

know, however, that we are a long way from 

having the necessary wildiife data to make 

the kind of decisions an ever-increasing 

scgrnent of the public is asking as to make, 

From a selfish standpoint, we can look 

to the increased funding and personnel ceilings that have and will accompany this 

increased interest in and concern for wildlife. All thLzt glitters iq not gold, howc3vccr, bcbcause the scope of our task will 

probably increase at a jircater rate than 

the resources needed to ds the job. There 

are 3,699 vertebrate spccies in the United 

States .ind avcrngc of 748 :;pec7ic.s in 

each state, An avcbr;ige cit 125 species per 

state nay no% be taken legally at prescribed places and times far commercial, 

contro 1 and recreation,ll purposes. h survev by the U.S. Fish and Wildlife Service 

showed that the states want to give attention to an average of 279 fish and wildlife species in each state. It is clear 

that traditional funding sources are not: 

adequate to do the job if we are going to 

be aggressive in recognizing the needs of 

nongarne wildlife, In addition, we will 

need to develop techniques for defining 

habitat reiiuirernents Like the one developed 

in the Pacific Northwest which relates 

wiidlife-timbcr relationships to timberrmnagemcnt ac. tivi ties . The resrrl t was tile 

ability to predict that "if Z do this, I 

can expect to get that." 

1 have disrrlssed briofly the history, 

need and justikication for an expanded 

program of wildlife management that would 

include nongame and game species. The 

question is, how iio wc. establish n program to fund nongnmr wildlife research and 

management when we can't completely fund 

the existing game management programs? 

The "Federal Aid In Nongame Fish and 

Wildlife Conservation Act of 1977"(5. 1140) 

was introduced by Senator Cary Hart 

(Colorado) and eighteen co-sponsors on 

?Larch 28, 1977. During hcarings held on 

S. 1140 on Xugusr 3, 1977, a strong record 

of support was compiled for the concept of 

a nongarrie bill, 

On July 25, 3977, Mr. ForsytBie and 

Mr, I,eg:;ctt introrlriced thc. "F1on;;nrnc Fish 

and Wildlife Conservation Act of 1978" 

(ti, R. 8606) in the Hoiisc, She Dill, 

whit.h providc2s f~nds for both planning and 

implcmcsntation, also rccei\ieii f,nrorclhle 

support. Tht. Xdrninisiltra~ inn, as it did on 

S. 1140, withheld support, 

The House has rontinueJ to work on a 

bill, and on December 7, 1977, Mr. Forsythtintroduc~d M,R. 10255, a refined version 
of W.R, 8606. It is a good bill and reflects 

more than 40 hours of work by the Cornittee 

legislative staff in cooperation with several 

conservation organizations. It provides for 

90 percent matching money for planning and 

75 percent for implementation. The planning 

portion lists 11 standards that, when adhered 

to, will help fill the voids in our knowledge 

of wildlife and its habitat requirements. 

Its major weakness is that it uses the authorized appropriation rather than an excise 

tax on certain outdoor recreational equipment and birdseed as the funding vehicle. 

The momentum is there for the passage 

of this legislation and I feel I can truly 

say that nongarne wildlife management is a 

need whose time has come. If I am right, 

or if I am wrong, we as professionals should 

consider ~eopold's (1933) words of wisdom: 

Management of Other Mild Life. 

The objective of the game management program is to retain for the 

average citizen an opportunity to 

hunt. As already pointed out, this 

implies much more than the annual 

production of a shootable surplus 

of live birds to serve as targets. 

It implies a kind and quality of 

wild game living in such surroundings and available under such conditions to make hunting a stimulus 

to the esthetic development, physical welfare, and mental balance 

of the hunter. 

The objective of a conservation program for non-game wild 

life should be exactly parallel: 

to retain for the average citizen 

the opportunity to see, admire and 

enjoy, and the challenge to understand, the varied forms of birds 

and mammals indigenous to his 

state, It implies not only that 

these forms be kept in existence, 

iu t that ,he grea tcs* possibZe 

varieq of tkm exis'$i in each 

cv"m?tiizi ~3. 

LITERATURE CITED 

Grange, Wallace B. 

1949, Way to game abundance. Charles 

Scribner's Sons. New York, New 'iiork. 

365 pp. 

Leopold, Aldo 

1933. Game management. Charles Scribner's 

Sons. New York, New York. 481 pp. 
The Relationship of Nongame Birds to Southern Forest Types 

and Successional Stages1 

3 / 5 / H. H. shugart,ll T. EI. Smith,- J. T. ~itchin~s,~' and R. L. Kroodsmh 

Abstract.--This paper identifies general patterns of 

southern nongame bird species at three different spatial 

scales - the region, the forest stand, the microhabitat. 

Three hypothetical examples of nongame bird management are 

developed. Each example uses available information on nongame bird habitat requirements and tools used by forest 

managers. Possible future approaches to nongarne bird management in the South are discussed. 

INTRODUCTION 

After several decades of research in avian 

ecology conducted by ornithologists in southern 

forests and elsewhere, we are in a position to 

generalize to a degree about the expected patterns of distribution of nongame birds over 

time and space, Two publications that may be 

useful for providing the reader with more 

detail are Slusher and Hinckley (1974) and 

Smith (1975). Fje will draw from these two 

volumes and current ecological literature to 

provide an outline of the general patterns of 

nongame birds and we will give some examples 

of approaches to managing nongame birds from 

our om research. 

One important aspect in considering patterns of nongame birds is to pay close attention to the time and spatlal scales that are 

being discussed. The general patterns of variation in nongarne birds over regional spatial 

scales may be quite different from the patterns 

of some smaller scale such as a forest stand. 

We will discuss the dominant patterns in nongame birds at three spatial scales: in the 

southern region, on study sites of 10 to 20 

hectares in size (the forest stand), and at a 

microhabitat scale (Less than .5 ha). Within 

these spatial scales, we will discuss longterm, annual and seasonal patterns of variation. 

The patterns are sumarized on Table 1 and more 

detailed references are given in the discussion 

that follows. 

L/Researeh sponsored in part by the 

Department of Energy under contract with 

Union Carbide Corporation and in part by the 

Eastern Deciduous Forest Biome, US-IBP, funded 

by the National Sciences Foundation under 

Interagency Agreement AG-199, DEB 76-00761. 

2'Research Ecologist , Enviromental 

Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830. 

yGraduate Student, Graduate Program in 

Ecology, University of Tennessee, Knoxville, 

Tennessee 37916. 

4i~anager, Environmental Park Project , Environmental Sciences Division, Oak Ridge 

Satioaal Laboratory, Oak Ridge, Tennessee 

39830. 

?/Manager, Environmental Analyses and 

Applications Program, Environmental Sciences 

Division, Oak Ridge National Laboratory, Oak 

Ridge, Tennessee 37830. 

DOMINAPJT PATTEmJS OF NONGm, BETRDS IN 

TWE SOUTHEW FORESTS 

We will discuss patterns of distributions 

of forest bird species in four of the nine categories in Table I. 

Long-Term Regional Patterns of Nongame Birds 

Over longer time scales (considering 

decade to decade or longer patterns of variation in bird distributions) , there have been 

several well documented cases of range extensions into the South. For example, such 

northern erratic migrants as the Evening Grosbeak and the Pine Siskin now occur regularly 

during some winters in parts of the South in 

which they had never Seen recorded before the 

present decade, There have been in the somewhat more distant past - a century ago - wholesale extinctions and regional extirpations of 

woodland species associated with the era of 

resource exploitation. Changes in species 
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ranges and the extinction (or potential thereof) of species can be summarized in two ways: 

(1) We can consider the patterns of overlap 

of species ranges to form a regional pattern 

of species richness fviz, areas in which many 

ranges overlap are species rich). We can 

then consider patterns of species richness 

over the South. (2) We can map the ranges of 

species that ere considered to be kn danger 

of extinction. 

Species Richness 

Several factors influecce the richness 

(mcas~~red In terns 05 the number of species) 

of tbe So~th's regional breeding avifauna, 

Regions that have considerable topographic 

relief or great heterogeneity of habitat 

types tend to have more species than otherwise comparable areas. Florida is depauperate 

(has less species than one would expect) for 

a region with both temperare and tropical 

habitats, This relative lack of species is 

due to the fact that Florida is a peninsula 

and is isolated by the Gulf of Mexico from 

the sources of tropical species that might 

otherwise occur there {Cook 1969)- ht is the 

depauperate nature of Florida that has allowed 

it to be a ""staging area" "for the invasion of 

exotic species ontc the Korth American coatinen t , 

in general, the greatest richness of nongame bird species is in the Appalachian 

region of the South. This richness is dce 

in part to the altitudinal changes in the 

region and in pare because the region is in a 

zone in which several species with northern 

affinities extend their ranges into the South, 

Table 2 provides a List of species occurring 

in these forests along with a general description of the species habitat preferences and 

nest site characteristics. 

Endangered Species 

If one maps the joint ranges of all of 

the so-called endangered bird species that 

occur in the South (Fig, I) the resultant pattern is the inverse of that for species richness, The endangered species tend to be 

distributed in coastal areas (or 92 the 

coastal plain) and in the southern part of 

the region. Of these endangered species, most 

are nor directly asscciased with forest habitats, but the Red-Cockaded Woodpecker (which 

is an old-age pine-forest endemic species) is 

often associated with areas that are managed 

for wood products, The managment of land on 

which an endangered species occurs is a very 

difficult endeavor both from a legal standpoint and in terms of the practical management 

aspects, Many of tke endangered species are 

Figure 1.--Overlaps in ranges of endangered 

species in the South. The darkest shading 

on the map indicates areas in the range of 

five rare or endangered bird species, the 

'lightest slladirlg indicates areas in the range 

of only one rare or endangered bird species, 

Intermediate shadings indicate 2, 3, or 4 

species increasing with intensits of map 

shadbng , 

rare birds that are associated with an ecologically unique habitat type (e.g., Cape Sable 

Seaside Sparrow) and management for these species is often a matter of avoiding any alteration in the habitat in which the species occur. 

Species such as the Red-Cockaded Woodpecker and 

perhaps the BacFrnan's idarbler are rare but also 

occur in transient habitats (respectively, oldgrowth pine stands, and disturbed southern 

swamp-forests). One cannot manage land for 

such species simply by Leaving areas alone that 

appear to be suitable habitat. Natural succession xiil transforz the habitat in time to some 

other habitat type. The management for these 

species sgould have to include the creation of 

new habitat in adjacent areas. The management 

of southern forests to inelude as an objective 

tkc perpetuation of transient-habitat endemics 

such as the 3ed-Gockaded I<oodpecker may be one 

of the most difficult tasks that the regional 

maahper ever has rc tackle. 
Table 2. Habitat preferences of birds that breed in woodlands of the eastern United statesa, and their abundance in eastern mountain hardwood forestrb 

during the breeding season 

Species 

Densi ty--pairs 

per 100 acres Forest type(s) (or frequency Nest sit 

preferredC in a1 1 ~tandsb)~ preferred3 

Occ ur r i ny-prj_n~rjbAr~ -- 

-- forest interior - 

Cooper's Hawk 

Sharp-shinned Hawk 

Broad-winged Hawk 

Ruffed Grouse 

ye1 1 ow-bi 11 ed Cuckoo 

Black-bi lled Cuckoo 

Barred Owl 

Saw-whet Owl 

Chuck-wi 11 's-widow 

Whi p-poor-wi 1 1 

Pi 1 ea ted Waodpec ker 

Red-bellied Woodpecker 

Yellow-bellied Sapsucker 

Ha i ry Waodpec ker 

Downy Woodpecker 

Great Crested Flycatcher 

Acadian Flycatcher 

Least Flycatcher IX Eastern Wood Pewee 

Black-capped Chi ckadee 

Carolina Chickadee 

Tufted Ti tmause Whi te-breasted Nuthatch 

Red-breasted Nuthatch 

Brulvn Creeper 

Winter Wren 

Wood Thrush 

Hermit Thrush 

Veery 

Bl ue-gray Gnatcatcher 

Gal den-crowned King1 et Sol i tary Vireo 

Red-eyed Vireo 

Bl ack-and-whi te Warbl er Swainson's Warbler 

Worm-eating Warbler 

Nashvi 1 le Warbler 

Parula Warbler 

Magnolia Warbler 

Bl ack-throa ted Green Marbl er Black-throated Dl ue Warbler 

Cerulean Warbler 

Ye1 low-throated Warbler 

Bl ackburnian Marbl er Pine Warbler 

Qvenbi rd 

Kentucky Warbler 

Hooded Warbler 

Canada Warbler 

Scarlet Tanager 

Rase-breasted Grosbeak 

between bark 

and trunk 

exposed roots U 

G 

G 

Densi ty--pai rs per 100 acres Forest type s (or frequency, Nest site 

Species preferred ) in all standsb) preferredd - ---- 12345 6789 

Sparrow Hawk (Anlerican Kestrel) 

Bobwhite 

Mourning Dove 

Carmon F1 i c ker 

Eastern Kingbird 

Wil low Flycatcher 

01 i ve-si ded Flycatcher 

House Mren 

Mockingbi rd 

Brown Thrasher 

Robin 

Eastern Bluebird 

Cedar Maxrri ng 

Whi te-eyed Vi reo Ye1 low-throated Vireo 

Warbling Vireo 

Prothonotary Warbler 

Go1 den-wi nged Warbler 

&I ue-winged Warbler 

Ye1 low biarhler 

Chestnut-sided Warbler 

Prairie Warbler 

Louisiana Waterthrush 

Yellow-breasted Chat 

Mourning Warbler 

Ainerican Redstart 

Orchard Oriole 

Rl ue Grosbeak 

Indigo Bunting 

Kufous-si ded Towhee 

Slate-colored Junco 

Chipping Sparrow 

Song Sparrow 

a 

G 

B 

0 

D 

U 

C 

a 

II 

U 

B 

0 

B 

U 

a 

n 

a 

G 

II 

U 

II 

U 

stream banks 

U 

G 

U 

a 

U 

U 

G 

u 

G 

Turkey Vulture 

Black Vulture 

Red-tailed Wawk 

Red-shoul dered Wawk 

Screech Owl 

Great-horned Owl 

Ruby-throated Humingbird 

Red-headed Woodpecker 

Blue Jay 

Common Crow 

Carol i na Wren 

Catbird 

Long-Terrc Patterns of Nongame Birds at the 

Scale of the Forest Stand 

Patterns in Erceding Bird Diversity 

Diversity indices as used by most ecologists (see MacArthur and MacArthur 1961; 

Patten 1962; Lloyd and Chelardi 1964; Monk 

1967; for various uses of diversity indices 

with different sorts of organisms) can he 

thought of as having two components: 

fiii3;IZne~s - the nmber of' species in a 

given comunity. 

Equitcebil:ty --- the evenness of n~merlcal abundance of the populations 

in a given comunity. 

For breeding bird comunities the diversity is mostly due to the number of species 

(richness) (Traner 1969; Kricher 1972) so 

that for studies of similar sampling inten2ity 

and size, diversi5y (often calculated as N = 

GpiLogpi, where K is the diversity index and 

Pi is the frequency of occurrence of the ith 

bird species) varies directly with species 

richness, The diversity index is not as 

strongly influenced by rare species as is a 

species list, and is useful in comparing 

studies of differing sample intensity (Buzas 

and Gibson 1969). 

There is a general theory that species 

diversity of organisms should increase through 

succession with a decline in diversity in the 

last successional stages (Margalef 1958). 

This pattern has not been uniformly noted in 

studies of breeding birds and is almost 

certainly not the case in winter bird populations. Adams (1908) listed species of birds 

characteristic of successional stages (aquatic 

comunities to bogs to climax forests) on Isle 

Royale, Michigan. Adams found a greater 

pariety of bird life (species richness) in the 

intermediate stages of succession. Figure 2 

(from Smith 1975) shows the pattern for three 

more recent studies. In no case is a decline 

in species diversity toward thc end of succession particularly evident, but there is a tendency for diversity to increase through succession, There is considerable variation in 

pattern amng the three studies. 

Patterns of Breeding Bird Density 

An increase of avian density through a 

progression of successional conamunities has 

been documented by Saunders (1936) in New 

Vork, Kendeigh (1948) in Michigan, Odum 

(1950) in North Carolina, Johnston and Odum 

(1966) In Georgia, Waapanen (1965) in Finland, 

Karr (1966) in Illinois, Karr (1471) in 

Panama, Shugart and James (1973) in Arkansas, 

FIELD j INTERMEDIATE FOREST j O ECOLOGICAL AGE INGREbSING ---+ 

Figure 2,--Changes in the species diversity 

index (Elp) for bird comunities during ecological succession. The Arkansas data are 

from Shugart and James (1373); Georgia data 

from Johnson and Odum (1950); Illinois data 

from Karr (1971). Figure modified from 

Shugart and James (l973), 

These findings drawn from diverse regions are 

in general agreement. There are notable 

exceptions to this general pattern [e.g,, 

Kendeigh (1947) found highest bird densities 

in shrubby sera1 stages of comunities in the 

Helderberg Plateau region of New Uork]. Nawever, there is an expected pattern of higher 

densities of birds in mature forests, 

Annual Changes in Bird Communities at the 

Scale of the Forest Stand 

A second time scale important at the level 

of the forest stand is that of annual or yearto-year variation in the composition of avian 

comunities. This annual variation can take 

two forms: variation in the population of a 

given species, and annual variation of the species composition of the comunfty as a whole, 

Figure 3 shows the annual fluctuations in the 

number of breeding pairs cf selected bird sFecies in an Illinois woodland over a period of 

years, 

The actual causes for such yearly fluctuations in species abundance are for the most 

part unknown, kjiens et al, (1974) found no 

clear relationship between fluctuations in 

population size of avian species and climatic 

variation, The problem of identifying causal 
1 

I i j 35 i ----- iWD CO 5li'l.TING '4 - W506 PEWEF / 1 

-"- - RCSE WREN 

30 

i I 

'up7 28 34 35 36 37 39 40 44 42 43 

YEAR 

Figure 3,--Number of pairs of selected species of breeding birds 5n Trelease Woods, 

Urbana, Illinois (55 acres). Data from 

Kendeigh (1944). 

factors is confounded by the fact that many 

of the breeding species in an area are migratory species whose densities may be a result 

of factors taking place in other areas of 

their range. Fluctuations may alSo be a 

result of cl.langes in dispersal (distributional) 

patterns rather than absolute numbers, Territory size in avian species has been found 

to be negatively correlated with abundance of 

food within the territory (Stcnger 1958; 

Schoener 1968). As a result of this, annual 

variations in the number of breeding birds of 

a particular species in a given stand might 

be a result of varying territory size resulting from variations in the food supply 

(i.e., insect biomass). 

Annual turnover of species in a stable 

vegetation type is rather Insi~nifdcnnt in 

mainland regions and usually reflects the 

presence of "rare species" encountered during 

censuses, The actual species composition of 

the dominant segment of thc avifaunn changes 

little from year to year for a given site. 

Seasonal Patterns in Bird 

?!"limohabitat Selection 

O~ie of the more interesting lines of 

research to develop over the past decade has 

been the use of multivariate statistical 

techniques to quantify the microhabitat sclection patterns of select nongame bird species 

usually within a season. Schoener (1974) has 

reviewed the manner in whiclt sllmilcnr species 

rlti31i~e their environments and has noted he 

following general patterns: 

I. The important variables involved in 

resource paftitloning are typically habitat 

variables, followed in importance by food 

variables. 

2, As the number of species considered in 

a conmunity increases, the number of vnr:;iblcs 

needed to separate the ccologicai roles of the 

species increase. 

Reccntly , there hnvc been loultivari,~te 

statistical analyst-s (Jnntcls 1971: Shugartand 

Patken 1972; Anderson and Shugart 1974; 

Whitmore 1975) directl-7 applied to drtcrmine 

the influence of a number of ilzrbitat variabLes 

on the distributions and microhabitats of cntire 

avian communities. These studies indicate that 

the simple relationship between bird specjes 

diversity and foliage height diversity first 

presented by FracAr"cur and MacArthur (1961) is 

neither as direct nor as universally applicable 

as it was first thoufcht. The application of 

multivariate analysis to the habitat selection 

problem in birds also seems to reduce problems 

in data interpretation, 

For example, one application of discriminant function analysis has been proposed by 

Conner and Adkisson (1976) to determine potcntial woodpecker inhabitation by measuring 

variables in the structural vegetation. Discriminant function analysis can also be applied 

to the entire woodpecker commuxlit-i in order to 

identify differences in structural niche 

requirements among sperirs, Using data collectczd by R, Bunnell on a study area on the 

Department of Energy Oak Ridge Reserv- tio on. n 

discriminant function was computed so that 

given the vegetational structure at a given 

point in space, the probability of the point 

being utilized by a given woodpecker sprcics 

could be determined. Vegetative data that corresponded to the parameters used in the wnodpecker habitat analysis had been collected for 

a number of inventory plots on thee 0;bk Ridge 

Itcx~xrvntion (i3unncLl cat- ,rl, 1478) i.;hcrti nci --- 

survey of woodpecker species have been made, 

These data were fed into the discriminant 

function and the most probable woodpecker species associated with each inventory plot was 

computed. The resultant map (Fig. 4) made with 

Spap (Dougnik and Sheeham 1975) shows the 

potential woodpecker feeding habitats by species for a site called the Haw Ridge Site. 

Such a map could be used bv a resource manager 

to void the areas that might be used bv a 

given woodpecker species or it might allow the 

placement of a nature trail so that a visitor 

could expect to see all the indipenot~s woodpecker species with minimum effort. The idea 

of coupling microhabitat analysis with the 

TIME (yd 

Figure 5.--Total acreage of Jack Pine in Michigan through 253 years of simu.lated succession 

with and withcut forest management. (Vertical axis in acres X 10~) 

In actual fact, to deal with this problem of declining habitat availability for 

Kirtland's Warblers under present co~ditions, 

selected areas of Jack Pine forest &re being 

set aside and periodically burnt to make 

available young stands of suitable habitat, 

The value of models such as the one above, 

is in their ability to predict long-term 

trends in the availability of habitat types 

under various management practices, In the 

above simulation, the harvesting of Jack 

Pine using the equivalent of a fifty-year 

rotation period appears to maintain the 

present status of Jack Pine as a forest 

type and thus halt the decline of available 

Kirtland's Warbler habitat, 

In this hypothetical example we have 

coupled a computer model (that projects 

the regional inventory of different forest 

types into the future) to the gross habitat preferences of a nongame bird species. 

Models which project future forest cover 

are being used and developed for forest 

systems for many regions of the United 

States. Some of these models even take into 

account economic feedbacks that might alter 

the harvest and site preparation options 

(for example) that are used (see Shugart 5 

al. 

- 1977 for a review of some of the more 

ecologically oriented models of thls sort), 

Given the existence of regional. "habitat 

projection models" - which is what the 

models used to project state forest inventories really are -we are in a position tc 

incorporate bird habitat preferences into these 

models and to manage nongame bird habitats. 

Stand Modeling of Nongame Bird Macagement 

Juqt as w2 can rzse rc Dona1 inventory projection models to predict "le chzlqpes of suitable habitat For specfes # - cr an cntiri state, 

we can ?il-o ol;ji c;tand s$x .,' #tors to assess 

effects of ~~Llernate rnflnr,t-c:rlent strategies on 

selected bLrd species or "or entire bird communities, Stand sinulati~r~ qodels are reviewed 

in Horn 1377; Shugart .Igr -ax, 1947, T5esse 

models are quite varied in the types cf mathematics used but they typically Function by considering the tree by tree changes ovw time for 

an area that corresponds to that of n canopy 

tree or to some sampling unit, The spatial 

scale of these models corresponds to the scale 

of what we earlier, termed the microhabi tat 

spatial scale for birds. 

As a hypothetical example, we took the 

stand simulator (FORET) that has been developed for East Tennessee (Shugart and West 1937) 

and used the model to simulate LOO0 years of 

natural succession an 100 s lots of forested 

land each of which is 1/12 ha (% 115 acre). 

This particular model functions bv keeping track 

of the diameter and species of each iqdividual 

tree occurring on the sirnula~ed plot, Each 

year, a probability of rnortalitz for each individual tree is detemiined ard a randoi- number 

is drawn to determine if a given tree should 

be killed, Similarly, acccrding tc conditions 

on the forest plot, trees of different species 

become established either by seeding in or by 

sprouting, Each year the diameter of each tree 

is increased according to the species and size 

of the tree and taking into account shading, 

crowding and climate, The output from the 

model is in the form of lists of tree diameters 

by species per 1/12 ha. This output looks like 

a stand tally sheet and is provided each year 
for each simulated plot. By combining the output from several replicate runs (usually 100) 

we can see the dynamics of a forest, Output 

frem the model, and a discussion of the validation of this model are in Shugart and West 

1977. 

The model output from 100 plots for 1000 

vears of natural succession was converted to 

bionass (in metric tons ha-'), We then apportioned this biomass between thin-barked tree 

spccies and thick-barked species. The thinhrked trees were the species thar the Yellowbellied Sapsucker might use for feeding, The 

Yellow-bellied Sapsucker (occurring in winter 

throughout che South) feeds on the inner bark, 

tree sap acd the insects drawn to the holes 

that the bird maintains in selected trees. 

Figure 6 shows the percentage of trees that 

20 

10 

0 

100 290 300 40C 500 600 700 800 900 1900 

TIME (years) 

Figure 6.--Thin-barked tree species suitable 

for feeding by Yellow-bellied Sapsuckers 

as a percentage of the total biomass 

through LOO0 years of simulated stand 

development on 100 1/12 ha circular plots. 

might be fed upon by Yellow-bellied Sapsuckers 

ddring 1000 years of natural succession in 

East Tennessee. There are two periods early 

and late in the succession in which sapsucker 

trees are particularly available but in no 

case is there a shortage of potential feeding 

sites during natural succession in the East 

Tennessee forests. 

There arc several logical extensions of 

this sort of habitat modeling. We could 

have increased the mortality probability for 

trees utilized by sapsuckers to obtain an 

estimate of the effect of this bird on the 

patterns of forest succession, i4e could 

harvest trees from the simulated stands and 

assess the effect of any stand management 

scheme on the availability of sapsucker 

feeding sites. Using multivariate statistical descriptions of habitat structure 

associated with different bird species, we 

could simulate bird cornunity changes under 

natural succession or under various management options. k%at is needed in tbis case 

is a stand projection model and a knowledge 

of species habltat preferences, 

FCTUiLSr: PRBBLEIIS IN NONT;k&E BIRD PifrVJAGEFIENT 

Through tbis discussion we have focused 

on the habitat preferences of southern nongame birds at different spatial and temporal 

scales. We have provided some general rulesof-thumb for patterns of bird populations and 

we have given three examples of what we feel 

will be the nature of future nongme bird management. It is imperative for the development 

of nongame bird management as a scientifically 

sound system of management practices that we 

learn more about the habitat requirements and 

niche relationships of nongame birds. Many 

temperate bird species (at least within a given 

season) seem to be closely tied to certain 

microhabitat features, This probably is not 

the case with a11 temperate species and seems 

not to be the case in general in tropical birds 

(Able and Noon 1976)- We must know which species are associated with which habitat elements 

and we must know which species cannot be managed by simply managing for habitat. 

It is probable that management for nongame 

species will be practiced in the less-economitally important mountain forests of the Arkansas 

and Missouri Ozarks and in the Southern Appalachians due to several ecological and economic 

factors. These forests are already used In a 

primary fashion for outdoor recreation so that 

the political pressures and incentives may be 

greatest in these regions for a concerted 

effort to manage song birds, Also these forest 

systems have a rich avlfauna, The economically 

important pine-dominated forests of the coastal 

plain should not be overlooked in terns of 

their potential for nongame bird management. 

The richer bird cornunities nay be in forests 

of the southern mountains, but not all species 

occur in abundance in these regions and some 

species are more or less endemic to the 

coastal plain and piedmont ecosystems. There 

is a potential for ignoring nongame bird populations in the pine forests that could create 

shortages in critical habitat for some species 

in the future, This potential problem should 

be recognized and avoided, 
We have identified txo areas In which 

tools and data faniliar to the forest manager 

could be used to atteipt t- apcimize birds 

and other uses cf forests, The first area involved the use of forest inventory data as 

habitat potential data for nongame s~ecies, 

The second area invgdved using stand and regional forests simclators to project bird 

habitat availabilitv intc the future, There 

is undoubtedly more to nongarne bird nanagment 

than simply habitat manageqent 5ut much work 

needs to be dorie 23 thls area, The insights 

of the forest-ento-wlfi~is: would be invaluable 

in studying food ava~iability for nongarrre 

birds, for example, Tbe richest research area 

an nongame bird mcragement ;n the future may 

well be the cosnbialng of tbe present understanding of avian ecology 1~15th the experience 

in managing forests, 

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Able, K. P., and B, R, Fioon, 

1976. Avian community structure along elevational gradients in the northeastern 

United States, Occoiogia 26:275-294, 

Adams, Charles C. 

1908. The eco1ogical succession of birds. 

Auk 25:109-153, 

Anderson, Stanley H,, and W, 2, Shrsgart. 

1974, Habitat selection of breeding birds 

in an East Tennessee deciduoxs forest. 

Ecology 55:828-837, 

Bent, Arthur C, 

1963. Life Histories of North iherican 

Wood Warblers, Part $1, Dover PubT, 

Inc., Mew Pork. 

BunnelL, Ronald C., J, Thomas Kitchings, and 

Charles £3. Procknow, 

1978. Analysis of structural niches of 

woodpecker species in an East Tennessee 

forest. Unpublished Fanuscript, 

Buzas, He A., and T, G, Gibson, 

1969, Species diversity: Eenthonic foraminifera in western Xorth Aelaneic, Science 

f63:72-75. 

Canner, R. N., and Gur~iq S, Adkisson, 

1976. Discriminant fu~ctiona: a~alvsis: 

A possible aid irL detcrainLnp the impact 

of forest managwent cn woodpecker nesting 

hakitat. F~rest Science 22:122-127, 

Cook, Robert E, 

1969, Variation in spec5es density of 

North American bir2e- Syst- ZooT. 18: 

63-84, 

Dsugenik, J, A,, and 9, 6, Shect::~, 

1975, Swap Users s Reference it";lcual, 

Laboratory for Cozputer Gra~5ics and 

Spatial Analysis, Barvard Grlversity. 

191 p* 

Kaapanen, A, 

1965, Bird fauna sf the Finnish forests 

in relation to foresr succession. Ann. 

Zosl, Fenclca 2~153-196, 

Worn, Henry S, 

1976, Succession, In: Robert M, May (ed,), 

Theoretical ~colojge Pr iniriples and A-pplications, X, B, Saunders Cc,, Philadelphia, 

Pennsy lvsnia, 

James, F, 6, 

1971, Ord5nations of habitat relationships 

among breeding birds. Wilson Bull, 83: 

215-236, 

Johnston, D, W., and E. P, Odurn, 

1956, Breeding bird populations in reiation to plant succession OR the Piedmont 

of Georgia, Ecology 37:50-62, 

Karr, J, R, 

1968, Habitat and avian diversity on 

stripmined land in East-Central Illincis. 

Condor 70~348-357. 

Karr, J, R, 

1971, Structure of avian cornunities in 

selected Panama and Illinois habitats. 

Ecoi, Monogr, 41:207-233, 

Kendeigh, S, C, 

1948, Bird populations and biotic comunities in Uorthern Lower Michigan. Ecology 

29:101-114, 

Kricher, Jolx C, 

1972, gird species diversity: The effect 

of species richness and equitability on 

the diversity index, Ecology 53~278-282, 

Lloyd, M., and R, J", Ghelardi. 

1964. A table for calculating the "equitabi1iry'"omponent of species diversity, 

J. Anin, Ecol, 33~217-225. 

NacArthur, R, H, 

1972, Geographical Ecology, Harper and 

Row Pubiiskers Iae,, New York, 

MacArthur, R. H., and J, W, XaoArthur. 

1961. On bird species diversity. Ecology 

42:594-598, 

Margalef, D, R, 

1958- Infarmation theory in ecology. Gen. 

Syst, 3~36-71, 

Monk, 6. 19, 

1967. Tree species diversity in the eastern 

deciduous forest with particular reference 

to north central Florida, her, Nat. 101: 

173-188, 

Odum, E, P, 

1950, Bird populations of the Highlands 

(North Carolina) Plateau Region in relation to piant succession and avian invasion, Ecology 31:587-505. 

Patten, B, 6, 

1962, Species diversity in net phytoplankton of Raritan Bay. J. Marine Res. 

20: 57-75, 

Saunders, A, A, 

1936, EeaSogy of the birds of Quaker Run 

Valley, Allegheny State Park, New York. 

State !-%IS. , Albany, New Vork, Handbook 

No, 16, 
Schoener, Thomas M. 

1968. Sizes of feeding territories among 

birds. Ecology 49:123-141. 

Schoener, Thomas W. 

1974. Resource partitioning in ecological 

comunities. Science 185:27-39. 

Shugart, H. H., and B. 6. Patten. 

1972. Niche quantification and the concept 

of niche pattern. In: B. C. Patten (ed.), 

Systems Analysis andsimulation in Ecology 

11. Academic Press, New York. 

Shugart, H. H., T. R. Crow, and J. M. Hett. 

1973. Forest succession models: A rationale 

and methodology for modeling forest succession over large regions. Forest 

Science 19:203-212. 

Shugart, H. H., and Douglas James. 

1973. Ecological succession of breeding 

bird populations in northwestern Arkansas. 

Auk 90:62-77. 

Shugart, H. H., J. M. Klopatek, and W. R. 

Emanuel . 1977. Developments in ecology in systems 

analysis and land-use planning. ORNL/ 

TM-6009. 

Shugart, H. H., and D. C. West. 

1977. Development of an Appalachian deciduous forest succession model and its 

application to assessment of the impact 

of the chestnut blight. Jour. of Env. 

Mgt. 5: 161-179. 

Slusher, John P., and Thomas ?I. Rinckley. 

1974. Timber-wildlife 3lanagement S~posium 

Proceedings. Missouri Academy of Science 

Occasional Paper 3 : 92-96, 

Smith, Dixie R. 

1975. Proceedings of the Symposium on 

Management of Forest and Range Habitats 

for Nongame Birds. USDA Forest Service 

Gen. Tech. Report VO-1. 

Stenger, Judith. 

1958. Food habits and available f ooc? of 

ovenbirds in relation to territory size. 

Auk 75:335-346. 

Tramer, E. J. 

1969. Bird species diversity: Components sf 

Shannon's formula. Ecology 50:927-929, 

Wiens, J. A. 

1974. Climatic instability and the "ecological saturation" of bird comunities in 

North American grasslands. Condor 76: 

385-400. 

Wiens, J. A., and Melvin I. Dyer. 

1975. Rangeland avifaunas: Their composition, energetics, and role in the ecosystem. 

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Report WO-1. 

Lfiitmore, Robert C. 

1975, Habitat ordination of passerine birds 

of the Virgin River Valley, southwestern 

Utah. Wilson Bull. 87:65-74. 
The Structure and Organization of Avian Csmmunities in Forests 

I I Sidney A, Gauthreaux, Jr .- 

Abstract,--The structure of bird comunities is presented 

in the context of Southwood's schema of ecological strategies 

and the habitat templet. Heterogeneity in space and tinre and 

their effects on the gradients of duratianal stability and of 

resource level and constancy are considered the underlying factors in community organization. These gradients are used in 

discussing species strategies and life forms, comunity process 

(succession), and comunity characters (spatial complexity, 

tsophic complexity, niche breadth, standing crop, turnover, and 

diversity). - 

INTRODUCTION 

The concept of comnxunity as an aggregate 

of organisms which form a distinct ecological 

unit defined in terms of flora and fauna is 

widely accepted, but it is also obvious that 

the concept includes complex dynamic interactions and properties of the component 

species. In this presentation I will give a 

broad overview of the structure of avian 

communities in forests. In discussing avian 

community ecology I should mention that it is 

a bit naive to speak of "avian" community 

ecology, because birds represent but a part 

(and some would say a rather insignificant 

part) of the total comsmity structure. 

Nonetheless, work on birds has contributed 

greatly to our knowledge of the structure and 

dynamics of ecological comunities, and it is 

this contribution I wish to stress in this 

paper. 

The uitimate objective in studying community ecology is to determine the nature and 

the relative importance of the factors controlling its composition; also, whether, to 

what extent, and why the comuni:y is changing 

with time (PieLou 19742, In order to achieve 

this objective it is necessary to define some 

measurable properties of the comunity as a 

whole and in so doing make possible cornparsons of the quantitative properties among 

several communities, As Pielou (1974) points 

"professor, Department of Zoology, 

Glernson University, Clemson, South 

Carolina 2 9633 

out, this is a necessary first seep toward an 

understanding of how corriinunities function, 

Thus, the study of bird comunities is the 

search for relations among measurable aspects 

of sets of bird species such as patterns of size 

or relative abundance among the species within s 

community and patterns of numbers of species that 

vary regularly from community to community 

(MacArthur 1971). 

Southwood (1977) has recently stressed the 

importance of time and space in terms of ecokogical strategies of species in comunities and 

emphasized that the strategies of the species 

have evolved to maximize the numbers of their 

descendents in the community, He has generated 

a schema in which various features of communities 

have been arranged against the axes of space and 

time (fig. 1). Southwood% schema will be used 

as a guideline in my treatment of avian community 

ecology. It should be noted that any consideration of avian communities involves treatrnenc of 

component specieshtrategies, community process 

(succession), and comunity characters (spatial 

complexity, trophic complexity, niche breadth, 

standing crop, turnover, and diversity), and 

these considerations will serve as the outline 

for my presentaticn, 

GOWONENT SPECIES STEATEGTES 

A number of recent studies have addressed 

life history strateggies from many different 

viewpoints, In a theoretical examination of 

optimal reproductive efforts, Schaffer (k974a) 

has relaxed the general assumption of environmental constancy, and Schaffer (1974b) and 

Schaffer and Rosenzweig (1977) have investigated 
HETEROGENEITY I M Tl ME COP"" SAME SPACE) -4- UMFAVOURASLENESS 

RESOURCE LEVEL AND CONSTANCY 

ADVERSITY SELECTION SPECl ES 

STRATEGIES 

WANEROPHYTES CRYPTOPHYTES LIFE FORMS 

NICHE 

BEADTH 

"$WQ)PHIC 

COMPLEX BIY 

COMMUNITY 

PROCESS CBMMUPI ITV CHARACTERS 

Figure 1,--Ecological strategies and kke habitat templet (after Southwood 1977). 

the problem of more than one Life history 

scrategy in a species, The influence of environmental certainty, trophic level, and 

resource availability in Life history strategles Rave been discussed by Wilbur et al, 

(L974), and they suggest that additional ecoLogkcdl dimensions, such as environmental 

predketabiiity and the relative trophic 

position of species may be important in the 

svoluk;cn of life histories, Nichols et al, 

;I9761 agree that attempts to explain life 

histories es outcomes of single selective 

pressures have actually obscured the 

evsl*~&io~f life history strategies, and 

they zdd that nunierous organisms inhabiting 

v=ri-rble environments exhibit. temporally 

dyna~kc reproductive strategies (see sLso 

CieseL 19761, Rlcklefs (1997) in a disc:~;s ion of the evolution of reproductive 

strareghes in birds suggests that the Civersity fn life histories .nust be sought 

prinarlly in eaviromental factors that 

directly influence fecundity, prereproductive 

suri~ii~orship, and adult rn~rt~~kity cznd in 

2ensity-dependent or fortuitozs relationships among those aspects o~ the environment, 

1977) has carefully examined the ideas and correlates of s- and K-strategists in an overview 

of life history tactics, and questions rhe 

validity of the underlying assumptions and 

theoretical. predictions that have flourished 

in the Literature, According to Stearns (l976), 

the key life history traits are brood size, size 

of young, the age distribution of reproductive 

effort, the interaction of reproductive effort 

with adult mortality, and the variation in these 

traits among an individual's progeny. The general 

theoretical problem is to predict which combinations of traits will evolve in organisms living 

in specific circumstances. Leon (1976) has 

addressed this problem in part by using optimal 

control theory, 

Sam bird species resemble r-strategists 

(see MacArthur and Wilson 1967) in that they 

have high reproductive potential (longer 

breeding seasons and raise more broods per year 

than do other species), extraordinarily catholic 

and unspecialized habitat preferences, high 

dispersal ability, and are competitively excluded 

from species-rich islands by K-selected species 

(Diamond 1975). These former species are called 

supertrarnps, and Diamond found that faunas dominated by supestrmps maintain population densities up to nine times higher than those of Kselected faunas of the same number of species, 

Pianka (1970, 1974a:90)hm t&~L;atee$ 

se-~eral tLars~--ceristics correlated with rci;d ~-4e~e~ti~1~ (Table 1). Stearns (1976, 
.ilubll-? 2,--Some of the Correlates of r and K Selection (After Pianlca 1970, 1974:90). 

---------* 

r Selection ii Selection 

Variable and/or unpredictable; 

uncertain 

- 

Fairly constant and/or predrctable; more certain 

Often catastrophic, nondirected, More directed, 6enslty 

density independent dependent 

Survivor ship Often Type 111 Usually Types I and I1 

Population size Variable in time, noneyuilibrim; Fairly constant in time, 

usually well below carrying egurlibrium; at or aear 

capacity of environment; un- carrying capacity of the 

saturated cornunities or portions environment; saturated 

thereof; ecologic vacuums; re- comunities; no recolocolonization each year nization necessary 

Zntra- and interspecific Variable, often lax 

competition 

Selection favors 

Length of life 

Usually keen 

1 Rapid development 1 Slower development 

2 High maximal rate of increase, 2 Greater competit~ve 

r ability max 

3 Early repr~duction 3 Delayed reproduction 

4 Small body size 4 Larger i~dy size 

5 Single reproduction 5 Repeated reproductions 

Short, usually less than 1 year Longer, usually more than 

L year 

Leads to Productivity Efficiency 

It should be emphasized that although 

some bird species may be thought of as rstrategists, birds as a whole, compared with 

many other groups of organisms (e,g,, insects), 

are more K-strategists on the r-K continuum, 

Southwood et al. (1974) have made brief 

reference to birds as r- and K-strategists 

and have concluded that while many vertebrate species may have arisen as a result 

of K-selection (in comparatively stable 

geological periods), many groups within these 

taxa have had their population parameters 

modified to conform to the habitats they 

occupy, Really successful K-strategists 

become precisely adapted to a very permanent 

(in generation terms) habitat type, they 

becone larger in size, and, because of their 

extreme K-type population parameters, they 

lose their plasticity for selection. hother 

clear and straightforward discussion of optimal life history strategies with some reference to birds can be found in Southwood (1976), 

Brewer and Swander (1977) have examined life 

ilklory traits as they influence the intrinsic rate of natural increase in forest, grassLand, and marsh inhabiting birds. They 

conclude that forests can probably he thought 

of as I=-selecting environments for birds, 

while grasslands and marshes probably are not, 

specifically "because vegetational fluctuations 

make particular areas unpredictably uncrowded or 

overcrowded. '* 

SUCCESSION 

The appearance of species population densities along the time axis during succession is 

fundamentally similar to that found along spatial 

gradients (see fig. 19, but the rate of change 

slows as the comunity matures (Whittaker 1975). 

The properties of succession have been thoroughly 

reviewed by Margalef (l968), Odum (1969), Horn 

(1974, 1975, 1976) , and Whittaker (l975), Succession is being viewed currently in the context of 

adaptations of individuzl species independent of 

any transcendent properties of the whole comunity (Drury and Nisbet 1971, 3.973; Connell 147%; 

Morn 19741, and the replacement process is increasingly being represented by Markovian models 

(Horn 1876), The mechanisms of succession in 

natural communities and their role in comunity 

stability and organization have been reviewed 

recently by ConnelL and Slatyer (1977). They 

have suggested that the sequence of species 

observed after a relatively Large space is 

opened up is a consequence of the following 

mechanisms. Species with broad dispersal powers 
and rapid growth to maturity usually arrive 

first and occupy empty space. These species 

cannot invade and grow in the presence of 

aduLts.of their OF~J or other species. Several 

alternative mechanisms may then determine 

wllich species replace these early occupants. 

Connell and Slatyer (1977) have proposed 

three models of such mechanisms, The first 

they call the "facilitation" model that 

suggests that the entry and growth of the 

larer species is dependent upon the earlier 

species '"preparing the ground," and only 

after this can later species colonize. The 

second they have referred to as a "tolerance" 

model which suggests that a predictable 

sequence is produced by the existence of 

species that have evolved different strategies for exploiting resources. Later 

species will be those able to tolerate lower 

levels of resources than earlier ones. The 

third model they have called the "inhibition" 

model which suggests that all species resist 

idvasions of competitors. The first 

occupants preempt the space and will continue 

to exclude or inhibit later colonists until 

the former die or are damaged, thus releasing 

tsswrces that permit later colonists to 

reach maturity. The first and third models 

have the greatest supportive evidence, while 

the second model has little supportive data. 

Kendeigh (1945) has long considered the 

general pattern of avian succession to be a 

manifestation of the habitat preferences and 

ecological requirements of the bird species. 

The replacement sequencing and habitat requirements of bird species during succession 

in a number of different communities have 

been examined (Adams 1908; Lack 1933; Grange 

1948; Odum 1950; Beckwith 1954; Johnston and 

Odum 1956; Ilartin 1960; Hitchell 1961; 

Haapanen 1965, 1966; Karr 1971; Glowacinski 

1972; Shugart and James 1973; Kricher 1973; 

Meslow and Wight 1975; Soots and Parnell 1975; 

Winternitz 1976), and all show that there is 

a high correlation between bird species and 

vegetation stage (fig. 2). Bond (1957) and 

Shugart and James (1973) have analyzed the 

correlation between bird and plant similarity 

coefficients betteen successional stages in 

comunities and found that the correlations 

were both strong and significant. 

The progressive changes in the composition and relative abundance of various bird 

species with the cropping of the forest on a 

40-year cycle in Burgundy, France, has been 

examined by Ferry (1960). He found that the 

birds could be placed in four groups according 

to their responses to the changing environment, The first group of birds settle in 

the low herbaceous or bushy layer with open 

spaces above it, increase in density, and 

then disappear quickly. The second group 

consists of species that arrive fairly 

quickly after the felling, increase in density, 

and then slowly decrease without disappearing 

completely (provided the forest is not pemitted 

to return to climax). The third group includes 

those birds that settle at a particular, more or 

less early, stage, increase rapidly at first, 

and then more slowly as the populations build up 

to their limit. The fourth group contains those 

birds t~hose populations passed through a maximum 

during the early stage, diminish or disappear 

when the undergrowth becomes too dense, and 

become abundant once again in the mature plots. 

Similar findings have been reported from studies 

undertaken in different environments, notably 

in pine forests in Britain (Lack 1933), spruce 

forests in Finland (Kaapanen 1965, 1966), and in 

several different comunities in America (Monson 

1941, Hagar 1960, Kilgore 1971, Curtis and Ripley 

1975, Webb et al. 1977). 

According to Southwood's (1977) schema (fig. 

I), certain comunity characters (spatial complexity, trophic complexity, niche breadth, 

standing crop, and turnover) change during suecession while some community characters (niche 

breadth, trophic complexity, and diversity) also 

vary in terms of resource level and constancy 

and in terms of saturation or interaction selection, exploitation selection, and adversity 

selection (see Whittaker 1975). It should be 

stressed that the aforementioned comunity 

characteristics are highly correlated and interactive and, consequently, it is almost impossible 

to discuss a given comunity character without 

making reference to another characteristic with 

which it is highly correlated (e.g., species 

diversity and trophic complexity). In the 

following sections f will examine the community 

characteristics given by Southwood (1977) with 

particular emphasis on birds. 

Spatial Complexity 

Through successional stages, the spatial 

complexity of a location increases and the 

variety of niches also increases, MacArthur and 

Levins (1967) have suggested that increasing the 

dimensionality of resources allows more species 

to inhabit a comunity, and MacArthur (1971) has 

emphasized that any habitat containing many 

kinds of patches will contain bird species appropriate to these patches. 

A number of studies have attempted to 

examine the relation between increasing spatial 

complexity of vegetation in a comunity and avian 

comunity organization (Cody 1974; Tomoff 1974; 

Wiens 1974, 1976; Willson 1974; Balda 1975; Roth 

1976; Pearson 1977). There is agreement that 

more than one measure of complexity is needed. 

For example, vertical measures such as foliage 
WOOD THRUSH 

HOODED WARBLER 

SUMMER TANAGER 

. .>' * . -. . ... .-. ' :. . . .' .-. .,..:..:,* >.,.*.. .- - . ' ; . . . -'..*.'. 

PRAlRl E WARBLER 

CARD1 NAL 

F 1 ELD SPARROW 

GRASSHOPPER SPARROW 

COMMCIN I TY - OAK-HICKORY 

TWE 

Figure 2.--The relationship between selected bird species and certain stages in old-field community 

succession. The differentia1 stippling in e bars for each species indicates 

relative abundance (based on Johnston and 0 

height diversity (MacArthur and MacArthur 

1961) and percent vegetation cover (Karr 1968, 

Karr and Roth 1971) do not measure horizontal 

patchiness of grain of the habitat (MacArthur 

1968, Levins 1368). Miens (1974) has developed a measure of heterogeneity for grasslands 

using the coefficient of variation, and Roth 

(1976) has done the same for four bird 

comunities in the brush-grasslands of south 

Texas. Spatial complexity or habitat heterogeneity must be expressed in vertical and 

horizontal spaces, and in bird studies vegetational complexity has been measured in terms 

of (1) relative plant species richness, (2) 

horizontal foliage heterogeneity, and (3) 

vertical foliage profile (see Cody 1974, 

Tomoff 1974, Rotk 1376, Pearson 1977). 

Xultivariate statistical analyses have 

been undertaken to determine the influence of 

a number of habitat variables on the distributions and microhabitats of entire avian 

communities (James 1971, Shugart and Patten 

1972, Anderson and Shugart 1974, Shugart et 

al. 1975), and these studies also indicate that 

single measures of habitat complexity as predictors of bird species diversity may not be 

universally applicable. Shugart et al. (1975) 

have suggested that multivariate analysis can 

be a powerful tool in identifying the important 

habitat variables for each species in a community. 

MacArthur et al. (1962) concluded that 

patchiness resulting from addition of layers was 

more important than the increased opportunity 

for vertical layering of birds. Karr and Roth 

(1971) found a sigmoid relationship which indicated that the sharpest increase in avian diversity occurs with the addition of the shrub and 

early tree layers and that added vegetation 

beyond that point produced diminishing returns. 

Willson (1974) also showed that the greatest 

addition of guilds (see Root 1967) takes place 

as trees appear. Roth (1976) found that while 

some new bird species can be absorbed in the 

additional patches in the transition from grassland to shrub-grassland, others may be vertically 
segregated because of the additional vertical habitat space. He further suggested 

that an increase in stratal specialists and, 

consequently, horizontal overlap (see Cody 

1974) occurs in the transition from shrubland 

to forest. Thus, according to Roth, it would 

appear that increased patchiness helps explain 

why shrublands have more species than grasslands, and by the same token, decreased 

patchiness may explain why forests have fewer 

bird species than some shrublands despite 

their having more vegetation layers or volume, 

Trophic Complexity 

Trophic complexity is a function of 

several factors including among others: (1) 

the number of trophic levels, (2) the number 

of species at each level, (3) the abundance 

of each species, and (4) the foraging strategies of each species. The complexity results 

from the interactions of the component species 

of the comunity, and these interactions can 

be characterized as being mainly predatorprey (e.g., the diversity of prey eaten) and 

competitive (e.g., the degree of competition 

with other species that is tolerated), Menge 

and Sutherland (1976) have examined predation 

and competition in relation to trophic complexity and have suggested that competition 

regulates the number of species in a guild 

only when the members of that guild actually 

compete, i.e., when they are near or at 

carrying capacity. They believe this is 

usually true at relatively higher trophic 

levels because of the absence of other controlling factors, e.g., predation. Conversely, 

they suggested that predation characteristically regulates the number of species present 

in guilds at relatively lower trophic levels. 

When they extended this hypothesis to betweencommunity and between-habitat comparisons, 

they predicted that in cornunities with few 

trophic levels, competition will be relatively 

more important than predation as an overall 

organizing factor. As the number of trophic 

levels and the number of species per level 

increase, predation will become relatively 

more important as an organizing factor. Menge 

and Sutherland (1976) further suggested that 

trophic complexity is related to temporal 

heterogeneity in that in areas of greater 

temporal heterogeneity (i.e., a less stable, 

less predictable, and more stressful environment) there is less trophic complexity with 

increased competitive exclusion. With regard 

to the relationship between complexity and 

stability, Hay (1976) believes that a predictable (stable) environment may permit a 

relatively complex and delicate balanced community to exist, while an unpredictable (unstable) environment is more likely to demand 

a structurally simple, robust comunity. May 

(1976) pointed out that as a mathemtical 

generality increasing complexity makes for dpamica1 fragility rather than robustness (but see 

McNaughton 1977). 

According to Southwood's (1979) schema (fig, 

I), trophic complexity decreases with increase6 

adversity (sensu LShittaker 1975), and this 

decrease is associated more with an increase in 

niche width than a decrease in spatial compl~xitj-, 

although the latter does occur. In contrast, on 

the durational stability axis of Sou~kwood's 

schema the relative importance of niche breadth 

and spatial complexity for trophic complexity is 

reversed. 

A new measure of distance from the food 

source to any member of a food web has been 

introduced by Kercher and Shugart (1975). The 

measure is referred to as effective trophic position and is defined as a function of energy ingested per unit time by a population and the 

production of the autotrophs necessary to maintain that population. Trophic position thus 

defined is a generalization of the trophic-level 

concept capable of describing complicated food 

webs and based on the concept of ecological 

efficiency, Pimm and Lawton (1977) have recently 

suggested that the number of trophic levels in 

a comunity may be constrained by population dynamics and not by ecological energetics. Gol.len 

(1977) has presented a new technique fur using 

food webs to gain information about the minimum 

number of dimensions of a niche space necessary 

to represent, in a specific sense, the overlaps 

among observed trophic niche, and he concluded 

that within habitats of limited physical and 

temporal heterogeneity, the overlaps among niches 

along their trophic (feeding) dimensions can be 

represented in a one-dimensional space. 

Considerable work has been done an predation 

and competition in birds in relation to comunity 

trophic structure, Some species differ both in 

food and habitat rather than either separately, 

and when a group of species exploits the same 

class of resources in a similar way in a community, 

the assemblage is called a guild (Root 1967). 

The spatial and temporal separation of some bird 

species has been correlated to food specialization and division of food resources (Edington and 

Edington 1972), and Schoener (1974) has discussed 

the underlying ways that similar species utilize 

different resources in their environment, With 

regard to birds, in considering the important 

particular dimensions in resource partitioning, 

habitat dimensions are more important than foodtype dimensions, which are in turn more important 

than temporal dimensions, and as the number of 

species considered increases, so does the number 

of important dimensions in resource division, 

In a thorough review of prey characteristics 

and the range of resources used by avian predators, 

Hespenheide (1975) concluded that bird species 

can be more closely packed in a community with 
respect to food than to foraging behavior, 

implying that it is easier to adjust behavior 

(e.g,, foraging zone or method) to avoid competition than to change food habits, Ccnsequently, as species are added to the comunity 

diets will remain as wide as possible, but 

foraging zones should contract, resulting in 

habitat specialists but food generalists. 

Morse (1911) has provided a detailed review 

of how and where birds forage for food, and 

Schoener (1971) has examined theoretically 

the feeding strategies of birds and other animals with emphasis on the energetic costs of 

different foraging methods, 

Currently, the established role of competition in structuring bird comunities 

(Cody 1974) is being questioned (Connell 

1375, Uiens 1977) because of the lack of experimental evidence in support of the idea, 

Connell (9975) has attempted to review the 

field evidence (of an experimental nature) 

in support of the existence of interspecific 

competition in birds and could find only one 

study (Davis 1973) indicating that one species 

excluded another from a particular habitat. 

However, this type of competitive exchusion 

has been proposed frequently to "explain" the 

within- or between--habitat or geographical 

segregations of certain bird species that 

show minimal or no overlap in their distributions (e.g.,. Terborgh md Weske 1975). 

Niche Breadth 

The concept of niche is closely integrated with spatial and trophic complexity, 

and it is often difficult to discuss one without making reference to the others. Before 

discussing the niche concept, a distinction 

among three aspects of the relationship of a 

species to environment should be reviewed (see 

T&ittaker et a1. 1973)- The area of a species 

is the geographical range, while the habitat 

of a species is co~posed of the physical and 

chemical environment as well as other factors 

(e.g,, elevation, topographic position), or 

sf a kind of community, The niche of a 

species is the species"osition in a comunity in relation to other species and is defined 

in terns of space, time, and functional relationships, The current theory of niche, as 

proposed by Levins (1968) and PlacArthur (2968) 

and recently sumarized and further developed 

by Vandemeer (1972) is based on the original 

definition of Hutchinsan (1953), More recent 

general discussions of niche can be found in 

ColwePL and Fuentes (L975), Pianka (l976), 

mittaker and Levin (L976), and Kroes (P977), 

Niche breadth, width, and size are frequently used as synonms in the literature, 

and all can be thought of as the sum total of 

the variety of different resources exploited 

by a species (Pianka 1476). In the absence of 

any competitors or predators, the entire set 

of resources utilized by the organism is referred to as the fundamental, pre-interactive, precompetitive, or virtual niche (see Vanderrneer 

19721, Rarely if ever in nature does a species 

exploir its fundamental niche, but rather its 

activities are curtailed or modified b53 other 

species (its competitors and predators) in the 

comunity, resulting in the speciesf rreaiized, 

post-interactive, or post-competitive niche 

(Vandermeer l972), Consideration of niche 

breadth necessitates consideration of foraging 

strategies with regard to specialization and 

generalization (see Orians 1971, Schoener 1971, 

Covieh 1976, Ellis et ale 1976, Norberg 1977, 

Pyke et al, 1977, Sih 1917). Measures of niche 

breadth have been provided by Simpson (19491, 

Horn (19661, MacArthur and Levins (1967), Colwell 

and Futu5nna (1971), Pielou (19721, Roughgarden 

(19921, Vandermeer (L972), Pianka (14751, May 

(1975a) , and Slatkin ad Lande (1976). In general 

niche breadth increases as resource availability 

decreases (Schaener 1971, MacArthur l972), 

Two fundamental components of niche breadth 

are the P'between-phenetyp~f' and the "withinphenotype" components (Roughgarden 1972, 1974). 

When individuals have little or no overlap in 

resources used (specialists), the niche breadth 

of the population has a high between-phenotype 

component, and in contrast, when individuals 

exploit the entire range of resources (generalists), the niche breadth of the population has 

a high within-phenotype component. The subject 

of niche overlap is yet another central aspect 

of niche theory (May and MacArthur 1972, Sabbath 

and Jones 1973, Pianka 1974b, May 1974, McMurtrie 

1976,.. Warner and Whitmore 19771, and as Pianka 

(2976) has pointed out, this subject has generated a nramber of concepts (e,g,, competitive 

exclusion, character displacement, limiting 

similarity, species packing, maximal tolerable 

niche overlap, and diffuse competition), It 

should be mentioned, however, that equating 

niche overlap with competition maybe on occasion 

a questionable practice and is often misleading 

(CoLwelL and Futu)mra 1971, Connell 197.5, Pianka 

3.996, Wiens 1977). Competitive interactions in 

comunities and their bases have been thoroughly 

discussed recently by Conae21 (19751, Pianka 

(l976), Levine (19763, deJong (L97h), and Wiens 

(i977), 

There has been considerable emphasis on 

niche theory in the work on avian comunities, 

Cody (1968, 1974) has carefully examined niche 

theory in his work on the role of competition 

in the structuring of bird comunities, and he 

has given detailed attention to niche ~readth 

and overlap in his treatrfient. Niche overlap 

has also been studied in feeding assemblages 

sf birds in New Guinea (Terborgk and Diamond 

2970), in the avifaunas of Australian islands 

(Abbott 1935), in passerine birds in the 
British West Indies (Ricklefs and Cox 1977), 

and in passerines in Swedish coniferous woodLands (ULfstrand 1977). AFerstarn et al. 

(1974) have studied the niche differentiation 

during winter in woodland birds in southern 

Sweden and on the nearby island of Gotland. 

Several studies have shown that bird 

species broaden their niches on islands by 

changing their vertical foraging distributions, but seldom changing their foraging 

behavior (Crowell 1462, Diamond 1970, Yeaton 

and Cody 1974, Diamond and Marshall 1977). 

The origin of differences in comunity 

structure, such as those between different 

islands of the same archipelago, between 

different Localities on the same island, 

between different adjacent habitats, and 

between different biogeographical regions 

have been reviewed by ~imond (1975). His 

hypothesis is that through diffuse competition, the component species of a community 

are selected and coadjusted in their niches 

and abundances so as to fit with each other 

and to resist invaders. The relationship 

between niche breadth and the amount of 

morphological variation within and between 

species has been examined by a number of 

investigators (Grant 1968, 1971; Willson 1969; 

McNaughton and Wolf 1970; Keast 1972; 

Rothstein 1943; ktespenhei.de 1975; Karr and 

James 1945; Willson et al. 19751, and 

although the results suggest that competitive displacement may be a particularly 

important determinant of avian cormunity 

structure, such comparisons may provide 

results that are misleading (Wilson 1975). 

Hespenheide (1975) has examined resource 

characteristics and consumer niche width in 

birds and has concluded that coexistence 

depends on maintaining minimum differences 

between species and, for strategic reasons, 

space and behavior are more easily divided 

than food directly in competitive situations. 

The data for foliage-gleaning species and 

for birds in general support this conclusion. 

Standing Crop and Turnover Rate 

Both standing crop (biomass) and turnover rate (productivity divided by biomass) 

vary during succession and as a result of 

the adversity of the environment (see fig. 

1). Standing crop and productivity increase 

throughout successional stages, providing for 

increased spatial complexity (%ittaker 

b975), but productivity frequently, but not 

invariably, fails in terrestrial coml.lrunities 

as the climax is reached (Margalef 1969) 

so that turnover rate invariably falls (Watt 

l971), Roit and Woodwell (in \hittaker 1975: 

175) "rave exmined secondary succession in 

the oak-pine forests of Long Island, New 

York, and have foucd in the first year of 

succession, net productivity is low an6 increases 

to a fairly stable level in the meadow stage. 

Through the shrub and young tree stage, net 

productivity increases more steeply in the young 

oak-pine forest, at 45 to 55 years, and this 

level stabilizes and persists in the mature 

forest. The growth of the forest can also be 

expressed by the biomass acc~~mulation ratio (the 

ratio of biomass to annual net productivity), 

and these rarios increase from about 1.0 in the 

annual stage, to 2-4 in the meadow stage, to 

4-7 in the shrub stage, to 10 in the 55-year 

forest and probably 25-35 in the mature forest 

(Holt and Woodwell in %ittaker 1975:175). 

Connell and Orias (1964) have suggested 

that greater plant productivity during succession 

should support greater diversity, everything 

else being equal. Productivity of the community 

should be positively correlated with the closeness of species packing (MacArthur 1971). Although rigorous data are scarce, there is 

nonetheless some evidence in support of this 

idea. Bird censuses in small areas of 4-6 

hectares of nearly uniform habitat show that the 

number of species generally increases with the 

productivity of the habitat. If one compares 

the mean net primary productivity per unit area 

(dry g/m2/yr) of "Idhittaker (1975 :226) with 

measurements of species diversity (Tramer 1969) 

in nine types of co~munities, a pattern emerges 

that suggests that the more productive forest 

communities have the higher number of species 

(Table 2)- Cody (1974 : 127) has also shown that 

the number of bird species and species diversity 

are, in part, correlated with comunity productivity. 

Glutz voa Holtzheim (k962), working in 

Switzerland on bird comunities, suggested that 

greater production in a forest habitat allows 

ir to support denser populations. Karr (1975) 

has also suggested that differences in productivity may be important in determining the number 

of individuals (not the number of species) that 

can breed in an area (but see Cody 1974:127-128). 

Several studies have examined changes in bird 

standing crop during succession and in different 

comunities. iCarr (1971) found a general increase 

in bird standing crop and existence energy as 

the ecological age af abandoned strip mine areas 

in Illinois increased, Similar findings have 

been reported by Sturges et al, (1974) and 

Shugart et al, (L975), In these studies there 

is general agrecsnrent that bird biomass and 

bird density increase in older comunities, but 

when bird biomass is plotted on bird density, 

the slopes of the lines are often different 

(see Wiens 1975:238), Shugart et aL, (1975) 

found that the general patterns of bird standing 

crop in the successional comunities studied by 

Shugart and Jmes (1973) was the same as the 

pattern of bird density, indicating that the 

average size of breeding birds did not fluctuate 
T&le 2.--Met Primary Production (Annual Basis) of Several Cornunities and Bird Species 

and Diversity* 

Net primary productivity 

S per unit area (g/m2/yr) t 

Marshes 

Grassliulds 

Shrublands 

Deserts 

Coniferous fores ts 

Upland deciduous forests 

Mixed forests 

.Floodplain deciduous forests 

Tropical woodlands 

*Productivity information after Whittaker and Likens in Lieth and Whittaker, 1975 :224 ; 

bird in£ omation after Tramer, 1969. 

i-Units are dry grams of organic matter per meter square. 

widely through the successional sequence. 

However, they did note that in ecotonal 

stages the size of birds tended to be larger 

on the average, and in the mature forests 

the mean size appeared to be somewhat 

smaller. Wiens (1975), in comparing 

different coniferous forest communities 

of North America, found trends in total biomass of birds similar to densities of birds, 

although the magnitude of fluctuation in 

biomass was more variable. In all coniferous 

forest types biomass increase occurs at 

different rates, The rate of increase is 

most rapid in northeastern coniferous forests 

and Sierra Nevada avif aunas and markedly less 

steep in northwestern, northern, and southeastern coniferous forests. This indicates 

that the increase in density in these latter 

regions is through the addition of relatively 

small-sized individuals to the avifauna, 

while comparable incremental increases in 

avian density in northeastern and Sierra 

Nevada forests involve the addition of individuals of larger mean size (Wiens 1975). 

Moreover, in northeastern coniferous forests, 

immature stands, supporting the same number 

of individuals as comparable mature forest 

stands, contain more avian biomass; hence the 

mean size of individual birds is greater in 

the immature stands. McNaughton and Wolf 

(1973:346-348) have done a similar analysis 

on the data of Johnston and Odum (1956), and 

the results are in agreement with the notion 

that during successional changes in the avifauna of a comunity, early stages support 

fewer species and individuals and less avian 

biomass than older stages, and the species 

tend on the average to be larger and ecologically more dominant. Consequently, 

d~ring succession the birds that invade 

tend to be smaller on the average than the 

species they replace. Breeding bird density 

and bird standing crop in coniferous forests 

and in grassland habitats when compared show 

some comparable results (Wiens 1975, Wiens and 

Dyer 1975). 

While standing crop of breeding birds in 

coniferous forests average 2 to 3 times that in 

grasslands, energy flow is nearly 10 times as 

great in the coniferous forest. This probably 

reflects the greater degree of dominance of 

extremely small species (forms which have relatively high energy demands per unit of body 

weight) in comparison to the larger species 

common in grasslands (Wiens 1975). Faaborg 

(1977) has examined the occurrence of nonpasserines in terrestrial avian communities with 

an emphasis on metabolic rates, activity levels, 

and resource availability. He concluded that 

the metabolically more conservative nonpasserines 

can support larger populations on a given amount 

of rare resource and expend less energy looking 

for these rarer resources. The differential 

occurrence of such resources in the tropics and 

in temperate areas probably explains why more 

nonpasserines occur in the tropics than in 

temperate communities. 

Wiens (1975) and Wiens and Nussbaum (1975) 

have reported that the avifaunas of coniferous 

forests in North America during the breeding 

season from 1 April to 7 October have an energy 

demand ranging from 10.7 kcal/m2/season in the 

dry, hot forests to 20.8 kcal/m2/season in 

moist, transitional forests. These figures 

generated by simulation models are in general 

agreement with the calculated energy demand of 

11.3 kcal/m2/year by the avifauna of an oakhornbeam forest in southern Poland (Weiner and 

Glowacinski 1975). In the latter study, the 

authors pointed out that approximately 50% of 

the annual energy demand occurs during the 

breeding season. 
Salt (1957) proposed that the ratio of 

consuming biomass to standing croD biomass 

of a comunity (CB/SCB) may be a measure of 

efficiency in food utilization in avian 

comunities, because cormunities dominated 

by large species that require Less energy per 

gram of body weight exhibit a greater discrepancy between consuming and standing crop 

biomass. A number of authors have concluded 

that there is an increase in comunity energetic efficiency (measured by the CBlSCB 

ratio) as succession proceeds towards the 

climax (Salt 1957, Karr 1968, Kilgsre 1971, 

Wiens 19751, but McNaughton and Wolf (1973: 

348) have noted that avian production efficiencies decline as succession proceeds in 

abandoned agricultural fields in the southeastern United States, Ecological efficiencies relating a trophic Level to the 

preceding level tend to increase up the 

pyramid of productivity, but net growth 

efficiencies usually decrease, because the 

percentage of food energy respired tends to 

rise along food chains. Consequently, net 

of production efficiencies need not increase 

up the pyramid; they may in fact decline 

(%ittaker 1975:217). 

The ratio of net productivity to biomass 

(P/B) or turnover rate decreases from grasslands to forest comunities. Thus the time 

it takes to replace the peak biomass completely at a given successional stage increases as succession progresses, Wow do 

bird communities respond to the different 

turnover rates of vegetation during succession? Shugart and Hett (1973) found that 

the bird species composition of a comunity 

changed more rapidly than the plant species 

composition although the pattern of change 

was the same between planrs and birds. 

Glowacinski and Jarvinen (19751 examined 

the turnover rate during secondary succession 

in forest bird comunities in oak-kornbeam 

forest in Poland and in Finnish coniferous 

of spruce and pine. They found that the 

shrub phase is characterized by rapid changes 

in the bird comunity and its rate of change, 

while the forest proper has a slowly 

changing avian cornunity and she rate of 

turnover changes relatively sPcwly* 

Species Diversity and Abundance 

The simplest cornunity attributes that 

can be measured are the number and relative 

abundmces of species in an area, It is not 

practical to study all the species sf a 

given cornunity, so that most workers have 

concentrated on a portion af a community or 

taxocene (e.g., birds, lizards, trees, ants). 

The term "taxocene" (Hutchinson 1967) means 

all the members of any taxoncmic group of a 

higher level than a species, The ermphasis 

on species cospositicn and abundance in 

cornunities d~~ring che 19se half century has 

resulted in a great ?dntsr of measurcaents of 

species diversitv for vsrious comunities 

(Williams 1964;, Inesa q-~antitative indices 

show the relati07 betwen corp~unity structure 

not only in acmSer of species but also in the 

relative nuxher of indivFd*~~ls of each species, 

There are a ~~urnbcr of different indices of 

species diversity, and each varies in what it 

shows (e,g,, Killrams 256L; Lloyd and Ghelardi 

1964; PieLou 1966, 1915; Zieban 1968; Lloyd, 

Zar, and Karr 1965; Ecri5ert 1471; Whittaker 

1972; DeBenedictis 1973; Peer 1974; Hair 1978), 

The Shacncn-Wiener function and the Simpson 

index are two of the most comionly used measures 

of species diverail;.-, Ideally the ShaanonWiener measure shouid be used only on random 

samples drawn from a large community in which 

the total number of species is known. The 

Shannon-Wiener measure combines two components 

of diversj ty: (1) nunbes of species and (2) 

equitability or evenness cf allotment of individuals among the species, In Simpson's index, 

relatively Little weight is given to the copmon 

species, Recently the ucility of diversity 

indices has been questioned in eeolagica.3. 

studies (Peet 1975)- The mssures of species 

abundance and diversity have been reviewed 

analytically by Msy {L575b), and May (2976 :1%8) 

has recently srgued for t2eszribin.g the com~unitg 

by its full distribution cf species relative 

abundance, and not trying to condense information into a single 8iversity index which may 

mislead and may oksscure valuable infomation 

on the few uccomon species in the coiwnunity. 

It is important to distinguish between 

species diversity measurements in a single 

natural comufiity and iL3 a large heterogeneous 

region, b%irtaker ($960) has defined three 

categories of species diversity patterns: 

(1) alpha diversity--the d3.versity in a sample 

dram from a single comnunity, often referred 

to as within-habitat diversity; (2) beta 

diversity--the diversity chat expresses the 

rate of species turccver between habitats, 

sometimes called between-habitat diversity; and 

(3) gama diversity--the total diversity found 

in a11 the avk-ailable habitats in a fairly large 

geographical area, Addicicnal considerations 

of these categories can be found in k%ittaker 

(1972), kkl;kr; (:975), Tri;mer (L974a), and 

Pielou (1975)- 

Dlverslty Gradients 

One of the most cons~icuous aspects of 

the geograpnlcab patterns of bird species 

distribution is the gsadi~nt in numbers of 

breeding bird species from the poles to the 

equator (Dobehensky 1950, XacArthur 1972:L99, 

Welty 1975:413). %re bird species occur in 
Figure 3.--The numbers of land bird species 

breeding in quadrants of 500 km per side 

in different parts of North and Central 

America (after MacArthur 1969 and 

MacArthur and Wilson 1967), 

tropical comunities than in temperate and 

arctic communities, and this pattern is 

found in most other terrestrial taxa of large 

enough size (Klopfer and MacArthur 1960, 

1961; MacArthur and MacArthur 1961; MacArthur 

et al. 1966; MacArthur 1969; Orians 1969; 

Karr 1971; Karr and Roth 1971; Schoener 

1971), The numbers of breeding land bird 

species in different geographical sectors 

and communities of North America have been 

computed (MacArthur 1965, 1969, 1972; 

PlacArthur and Wilson 1967; Cook 1969; 

Tramer 1969, L974a; Peterson 1975), and as 

Tramer (1974a) shows, during the breeding 

season the alpha diversity for bird species 

does not change significantly from 45ON to 

25*N, but from 2S0N southward, alpha diversity increases as one moves toward the 

equator, Gama diversity of breeding birds, 

on the other hand, differs in both eastern 

and western North America, In the East, 

gamma diversity decreases from 4S0M southward to southern Florida and the northern 

coast of the Gulf of Mexico, In the West, 

gamma diversity increases all the way to the 

equator (fig, 3). As can be seen in figure 

4, during the winter the numbers of land 

bird species in different communities and 

regions of North America have also been 

Figure 4.--The numbers of land bird species 

wintering in quadrants of 500 km per side 

in different parts of North and Central 

America (after Tramer 1974a). 

examined (Bock and Lepthien 1974; Tramer 1974a, 

1974b), and in winter both the alpha diversity 

and gamma diversity of bird species increase 

southward (Tramer 1974a). 

Tropical mountain-top communities have 

fewer bird species than would be expected on 

the basis of geographical Latitude (Orians 

1969, Kikkawa and Williams 1971, Diamond 1973), 

and although these communities have mean annual 

temperatures and short heights of trees more 

typical of temperate zones, there is no winter, 

Even though fewer species occur in mountain 

communities at higher altitudes, Terborgh 

(1971) has pointed out that in Peru an altitudinal transect showed more forest bird 

species than the entire eastern United States. 

Certain comunities have a higher avian 

species diversity than others (e.g., Margalef 

1963, 1968; Recher 1969; Tramer 1969; Karr 

and Roth 1971; Cody 1974; Rov 1975; Reese 197S), 

and bird species diversity usually increases 

during succession (e-g., Kricher 1973, 

Shugart and James 1973, Hamilton and Noble 

1975). What are the factors responsible for 

higher species diversities in cornunities as 

one moves toward the equator, and why do certain 

cornunities have higher species diversity 

indices than others? 
PLANT-SPECIES OIVERSI f Y FOLIAGE-HEIGHT DIVERSITY 

Figure 5.--Bird species diversity in deciduous forest plots of eastern United States in relation 

to (A) plant species diversity and (B) vegetative structure (after MacArthur and MacArthur 

1961). 

Determinants and Correlates of Diversity 

In an effort to determine what factors 

account for species diversity in selected 

forest types, MacArthur and MacArthur (1961) 

found that from the layering of the vegetation alone they could predict the number of 

breeding bird species in temperate deciduous 

f~rests and that further knowledge of the 

number of plant species did not improve the 

understanding (fig, 5A and SB), They concluded that height profile of foliage density 

in the layers 0-2 feet, 2-25 feet, and greater 

Than 25 feet is intportant in determining bird 

specles diversity, and they felt that these 

three layers correspond to different configurations of foliage--herbs, shrubs, and 

trees over 25 feet tall--in five acres of 

habitat (see MacArthur and Horn 1964). The 

height profile of foliage density is in 

fact a major component of the floristic 

community that allows birds to specialize 

on a particular part of the habitat 

(Flacftrthur 1964, Karr and Roth 197L, Cody 

1975, Roth 1976). 

That birds restrict their activities 

to different levels within a forest is well 

known, Even though birds are highly motile 

they are nonetheless characteristic inhabitants of a particular forest stratum, or 

even a particular Level within a given 

stratum, Colquhoun and Morley (1943) in a 

paper on the relative stratal abundance of 

12 species of birds in Bagley Wood in 

England found that the majority of species 

utilized several strata with a particular 

stratum of abundance for each kind of bird. 

In an alnlost pure stand of Quercus robur, 

they identified five strata utilized by the 

birds: (I) upper canopy (above 35 feet), 

(2) tree (15 to 35 feet), (3) shrub (4 to 15 

feet), (4) herb (3 inches to 4 feet), and 

(5) ground, Similarly, Kendeigh (8945) found 

breeding warblers generally stratified (or 

even substratified) in a sugar maple-beechhemlock forest near Albany, New 'Sork, and 

concluded that diversification in niche requirements reduced interspecific campetition 

and permitted a greater and more varied population to inhabit an area. Gibb (1954) studied 

coexistence in the Parids of Britain and 

demonstrated that different species fed in 

different strata when several occurred together in the same habitat, In structurally 

simpler habitats than forests (e.g., grasslands, 

fields, and marshes), the opportunities for 

within-habitat segregation are less, and there 

are fewer bird species per unit area (Cody 

1968, Wiens 1969). Cody (1974:29) pointed out 

that in habitats taller than 3 feet vertical 

stratification is the single most inrportant 

factor in the segregation of speciesP feeding 

activities, 

Orims (1969) found that the number of 

bird species in Costa Rica was not correlated 

with the number of tree species but was 

closely associated with foliage height diversity. The same is true for the southeastern 
portion of Australia near Sydney (Recher 

1969). In Puerto Rico, MacArthur et al. 

(1966) found vertical foraging ranges 

expanded, and species diversity was predictable when only two layers of vegetational 

height profiles were considered. Similarly, 

the vertical foraging range of birds was 

found to be expanded on species-poor islands 

in Panama Bay in comparison to mainland 

Panama (MacArthur et al. 1972). Karr (1971) 

likewise found that vertical foraging ranges 

in Illinois were more expanded in comparison 

to Panama, thus documenting the narrower 

vertical foraging ranges of tropical species. 

Pronounced vertical stratification has also 

been found in a dry forest in Peru, and 

moreover the vertical foraging ranges of 

many of the species shift as a function of 

time of day (Pearson 1971). 

Although the number of species and 

their abundance can be predicted accurately 

on the basis of height profiles of foliage 

density, MacArthur (1964) failed to predict 

just what bird species would be present in 

the complex habitats on the slopes of the 

Chiricahua Mountains of southeastern Arizona. 

Additional findings do not support MacArthur's 

foliage profile hypothesis. Balda (1969) 

failed to find a significant correlation 

between bird species diversity and foliage 

profiles in ponderosa pine and oak-juniper 

forests in Arizona. Although juniper was 

the most abundant tree in the oak-juniper 

forests and had a good fit for bird use 

according to the height distribution of 

the foliage, juniper was sparsely used by 

the birds. Instead the birds used the two 

species of oak more heavily, and all parts 

of a tree were used by the several bird 

species. Total bird use of Douglas fir 

foliage by height class was not correlated 

because there was a large proportion of low 

foliage that was underused while the upper 

heights were overused. Consequently, the 

very few tall Douglas firs in the area were 

used greatly out of proportion to their 

availability. Marshall (1957) has earlier 

reported similar findings in his studies of 

bird utilization of pine-oak habitat in 

Arizona. In the latter two cases the birds 

were probably showing within-habitat segregation (e-g., (a) different parts of trees or 

bushes, (b) different species of plants, or 

(c) different sections of the habitat 

characterized by overall differences in vegetation structure) (Cody 1974:23). 

Tomoff (1974) related bird species diversity to some measures of vegetative cornplexity (plant densities, foliage height 

diversity, and physiognomic coverage diversity) 

and found that the physiognomic coverage 

diversity (life forms divided into categories) 

was significantly correlated with bird species 

diversity. Tomoff (1974) concluded that plant 

species diversity may be highly important to 

desert breeding birds because each plant 

species may have peculiar properties which are 

needed by the birds for breeding. Additional 

shortcomings of using only foliage height 

diversity to predict bird species diversity 

can be found in Balda (1975), Reese (19761, 

Roth (l976), and Pearson (1977). 

Temporal Aspects 

Most studies of bird species diversity in 

various cowunities have concentrated on 

breeding birds, and the seasonal aspects of 

avian diversity in the community have been 

largely ignored. Stewart et al. (1952) found 

that the composition of the avifauna changed 

throughout the year in Maryland with the 

greatest number of species occurring in the 

spring and the greatest number of individuals 

occurring in the fall. Kricher (1972) and 

Holmes and Sturges (1975), working in the New 

Jersey piedmont and in New Hampshire, respectively, noted that bird species diversity 

decreased from summer to winter as a result of 

fall migration. Dickson (1974) found that 

species diversity in a bottomland woods in 

Louisiana increased from summer to winter, 

indicating that there were more overwintering 

migrants in the area than breeding migrants. 

Cody (1974:154), working in the Santa Monica 

Mountains in southern California, and Reese 

(1976), working in the piedmont of South 

Carolina, found that bird species diversity 

increased from summer to winter in certain 

habitats but remained the same or decreased 

slightly in other habitats. These results 

based largely on alpha diversity measurements 

are in general agreement with the summer and 

winter gamma diversity measurements of Tramer 

(1974a). Clearly, considerably more work is 

needed on the seasonal dynamics of avian 

community ecology if we are to gain a better 

understanding of how avian communities are 

structured and organized. 

EPILOGUE 

In this presentation I have attempted to 

present an up-to-date overview of avian community ecology. My overview is fairly representative but not exhaustive. Ecology as a whole 

and avian ecology specifically is in the process 

of undergoing major revisions and reassessments 

(see Foin and Jain 1977). A few years ago 

complexity of the cornunity was thought to 

impart stability to the community, but rather 

recently we have increasingly appreciated that 

stability (e.g., climatic stability) is a 

requisite for comaunity complexity, and when 

stability is not present complexity cannot be 

achieved, Less complex communities cope better 
with adverse and unpredictable environments. Goodman (1475) has recently critically reviewed the diversity-s tabili ty 

relationships in ecology and concluded that 

there is no simple relationship between the 

two, Competition bas long been the cornerstone of niche theory, but lately some 

serious doubts have emerged regarding c21.e 

role of cometition in shaping diverse 

comunities , and predation is being examined 

more closely, Likewise, many avian ecologists have been content with accepting 

foliage height diversity as the best predictor of bird species diversity, but 

several relatively recent studies have 

cautioned that foliage height diversity must 

be considered but one of many "dimensionst' 

and factors dictating bird species diversity ; 

bird behavior and climatic factors are 

receiving more attention. Avian communities show seasonally rhythmic changes, but 

there has been little appreciation for this 

fact as the preponderance of breeding season 

studies attests. We have much to learn of 

the e n e r g e t i c e f f i c i e n c i e s of the avifauna 

in a comunity throughout the year and from 

year to year during succession. In depth 

experimental (mmipulative) field studies 

of avian communities are needed if we are to 

make meaningful statements about man's 

influence on bird communities. We do have 

some knowledge of the structure and function 

of avian communities, but clearly much, much 

more remains to be done, Theory abounds 

and is very much in vogue, but carefully 

detailed empirical findings are needed most . 

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Tuesdav Af ternom, January 24 

Effects of Management Practices 

on Nongame Birds 

?loderator: Fred Kinard 

tJcstvaco Corporation 
Effects of Management Practices on Nongame Bird Habitat 

in Longleaf-Slash Pine Forests 

1 / Gene W. Wood and Lawrence J. NilesAbstract.--Increase in numbers of habitat niches that develop with increasing stand complexity is important to raising 

the species richness and abundance of non-game birds in longleaf 

and slash pine forests. Some silvicultural practices decrease 

complexity while others increase it. Practices which lead to 

eradication of the understory, destruction of dead trees and 

generally promote monoculture appear to be deleterious to nongame bird populations. 

INTRODUCTION 

The approach of this paper will be largely a theoretical discussion of the response of 

non-game bird populations to habitat changes 

caused by silvicultural practices in longleaf 

(Pinus palustris) and slash pine (g. elliottii) 

forests. Non-game birds will be discussed 

collectively with very little emphasis placed 

on individual species. This is necessitated 

by the dearth of published literature on nongame bird response to silvicultural practices 

in the southern pine forests. 

LONGLEAF-SLASH PINE TYPE 

Longleaf pine occurs naturally in portions of 9 southeastern states in a climatic 

zone characterized by long, hot summers and 

mild winters. The main longleaf pine belt is 

found on the Atlantic and Gulf Coastal Plain, 

though it extends into the Piedmont and Appalachian borders. Soils are characteristically 

sandy in texture, low in organic matter, have 

good to excessive drainage, and are low in 

fertility. (USDA 1965:384-385) 

Slash pine, in general, can be grown 

wherever longleaf grows although its natural 

range is considerably more restricted. The 

natural range extends from southern South 

Carolina to central Florida and southeastern 

Louisiana although it has been planted as far 

north as North Carolina and west to East 

1/ The authors are associate professor 

and fGrestry aide I1 at the Belle W. Baruch 

Forest Science Institute of Clemson University, Georgetown, South Carolina, 29440. 

Texas. Soils are typically sandy and range in 

drainage from well drained to poorly drained. 

The wet soils of pond margins are inost productive. (USDA 1965:458-459) 

There are 1.8.3 million acres of land in 

the longleaf-slash pine type. Five percent of 

this land is in natural forest and five percent in other public holdings. The forest industry owns 33 percent of the longleaf-slash 

pine type with 57 percent in other private 

holdings. (USDA 1973:304-305) 

Within the geographical range of thelongleaf-slash pine type there are 68 species of 

birds that are year round residents, 40 of 

which are associated with pine forest habitat. 

There are 106 summer residents and 112 winter 

residents of which 49 and 54 respectively are 

associated with pine habitat. (Bent 1937, 

1938, 1939, 1940, 1942, 1946, 1948, 1949, 

1950, 1953, 1968; Robbins et al. 1966, Harrison 1975, Bull and Farrand 1977) 

The influence of silvicultural practices 

on wildlife is based on the principles of the 

relationships of plant community complexity 

and productivity to habitat niche variety and 

carrying capacity, The habitat niche is the 

assimilation of environmental components necessary for a species to maintain and sustain 

life. The habitat is a more inclusive term 

and refers to the general environment and 

plant associations within which a species is 

found. In this paper the habitat is the 

longleaf-slash pine forest type. In principle, habitat niche variety is directly related to habitat complexity and is the deter- 
minant of the variety of animal species that 

can be accomodated. Simple plant comunities, such as an even-aged monoculture, will 

not support as large a number of bird species 

as a more heterogenous comunity. The habitat niches simply are not there, In the 

forest, a tract of land with a wide variety 

of stand conditions can be depended upon to 

provide the habitat niches for a wide variety of bird species. Similarly, within a 

given forest stand vertical structure complexity will determine habitat niche availability with the most structurally complex 

supporting the widest array of bird species. 

Carrying capacity is the number of individuals of a species that can be accommodated in a given habitat niche. In general, in natural comunities, the size of 

the array of niches and their respective 

carrying capacities are expressions of site 

productivity potential. The potentially most 

productive sites in terms of dry matter productivity will usually support the most structurally complex and species rich communities. 

In addition to the wide variety of bird species that can be supported, relatively large 

numbers of individuals within these species 

will occur in these communities. This phenomenon in forest communities can be changed 

by silvicultural procedures. The implementation of procedures that channel nutrients, 

water, and energy into single plant species 

tend to greatly reduce natural complexity. 

This decreases the size of the array of niches 

and consequently species diversity, an expression of numbers of species and individuals 

within species, of non-game birds, 

Data that support these principles with 

respect to non-game bird populations have 

been published by Saunders (1936), Kendeigh 

(1948), Odum (1950), Johnston and Odum (1956) , Bond (1957), MacArthur and MacArthur (1961), 

MacArthur et al. (1962), Karr (1968), Davis 

and Savidge (1991), Shugart and James (19731, 

Kritcher (1973), and Roth (1976). 

COmLEXITY WITHIN ABD AMONG STANDS 

As previously stated a wide variety of 

habitat niches may be available in a forest 

that has a wide variety of stand conditions, 

i.e,, successionaL stages and compositions of 

species. The complexity or heterogeneity in 

this area is referred to as beta-diversity. 

The forest manager's ability to create a 

forest mosaic that will support a species 

rich and diverse non-game bird population 

will depend on his ability to govern stand 

size, stand structure, and juxtaposition of 

stands. 

The primary unit that the forester deals 

with is the stand, which is itself a plant 

community. The silvicultural treatments 

applied to the stand will determine its individual complexity or heterogeneity or 

alpha diversity. In addition, the natural 

changes in stand complexity concurrent with 

natural development are important to recognize in order to know what portions of the 

forest are providing the habitat niches and 

various levels of carrying capacity for 

givtn birds, For these reasons this paper 

will be confined to the influence of silvicultural treatments on stand complexity as 

it relates to rafsing and lowering the number of habitat niches. 

REGENERATION CUTTING 

The time of the final harvest of longleaf and slash pine stands is also the time 

of the beginning of the new stand. Three 

general methods of harvest may be used in 

these timber types and the method used will 

determine the nature of non-game birdhabitat. 

The methods are seedtree, shelterwood, and 

clearcutting followed by planting. Each of 

these methods is preceded by prescribed 

burning for seedbed preparation. At this 

point there are two habitat parameters in 

which changes wrought by the silvicultural 

treatment will be reflected in bird response. 

These are the conditions of the understory 

and the existence of dead trees left standing. 

Generally, seedtree and shelterwoodcutting will lower the carrying capacity for 

overstory species but may raise it forunderstory birds. In these methods, prescribed 

burning will usually be carried out in the 

fall of good seed years and followed by log-' 

ging. While much of the aerial portion of 

the understory may be killed by the fire 

most of the woody stems will remain standing. 

Enhancement of the non-game bird population 

may stem from several causes. First the destruction of the litter layer exposes quantities of seed that normally would have gone 

undetected by birds foraging in the winter 

habitat. Flocks of wintering sparrows, Robbins and Dark-eyed Juncos will frequently be 

seen taking advantage of this forage resource. 

In addition, where the woody understory is 

sparse, small mammals will be made more vulnerable to birds of prey. Sharp-shinned, 

Sparrow, Red-tailed, Coopers and Red-shouldered hawks may be seen hunting on recent 

burns. Second, the stand understory will 

make significant recovery in the first growing 

season following treatment. Many of the hardwood seedlings, shrubs and perennial herbs 

will resprout the following spring. Spring 
nesting cover will in large part be missing, 

but foraging opportunities should be relatively abundant by mid-growing seasan, 

Seedtree and shelterwood nethods have 

minimum adverse impact on the bird popuiatioa. The degree of i~pact will depead upon 

the amount of residual overstory left standing and the length of time before the residual is removed, Becase of the heavier seed 

of longleaf, more residuaLs are required to 

insure adequate distribution of seedlings 

than is the case ir, slasil, Walker jl9ei.2) 

recomended 10 to 12 seedtrees per acre to 

be left in a seedtree cut for Loagleaf er 

alternately 40 trees per acre i? a ncdified 

shelterw~od with residuals being removed in 

about two years. Croker and Boyer (1975) 

recomended 30 sq. ft. of basal area be left 

of seedbearers in a Longleaf shelterwood, 

hi this interim period from time of the regeneration cut to the time of the removal of 

the residuals the habitat is generally productive following either method but mostly 

for the shelterwood, Bennett (1965) recornmended 4 to 6 seedtrees per acre in seedtree cuts and a basal area of 20 to 3Osquare 

feet in a shelterwood for slash pine with 

residuais being removed about one yearafter 

regeneration establishnent, The existence 

of a broken overstory and a developing understory of seedlings, shrubs, and herbs is a 

complex habitat and one which has ccnsiderable niche diversity. Carrying capac'2t.y 

for overstory bird spxies will be governed 

by the heaviness of the cut w5iI.e carrying 

capacity for understory bird species will 

be regulated by the vegetation response 

which in turn will be regulated by nutrient 

and moisture avaiLability. Pine Warblers 

will be abundant in these stands in. all seasons of the year, Once the understory develops Yellowthroats will also be cormon, 

Spring and summer birds n;ay include Summer 

Tanager, Great-crested Flycatcher, Prairie 

Warbler, and Blue Grosbeak, 

Clearcutting followed by intensive site 

preparation and planting has the most dramatic impact of the harvest 2nd regeneration 

techniques on forest bird habitat, It is a 

technique employed in slash pine where the 

stand be managed on a short rotation 

usually not exceeding 35 yezirs, It lil8y be 

emgloyecr? in 1ongledf stands 0.1 s-ery pro-- 

ductive sites in the heart of tke longL~af range alocg the Gull Coast from 

Lciislana to western Fisrida, 

This procedure essentialiy eliminates 

bird habitat for a short period of time, The 

cverstory is completely rernoved in ehe harvest 

and the remaining vegetation destroyed during 

site preparation, Chopping, disking, burning, 

and buildozing slashings, stumps and roots into windrows lea-~es ~ssentially a bare seik surface with little forage and no protective 

cover. The comwaniky is in its simplest structure and niche diversity and space are at a 

minimum, The windrows created ameliorate the 

situetion to some extent, They wlLl c~ntain 

sore cover f3r shslter axd escapz, In addition, 

since the sckl in the windrows is aixost entirely top soil and c2ctains large quantitfes of 

seed, dense vegetation rt.ill develop in the 

first growing season after treatment and offer 

both foraging and escape cover. 

Clearcutting with natural regeneration 

has a much less destructive effect. In this 

case prescribed fire is used to prepare the 

seedbed before harvesting, After seedfall, 

the stand is harvested and seed germination 

occurs shortly thereafter, In this treatment 

there is drastic impact on birds that include 

the overstory as part of t5eir ilickre but understory species may be enhanced, 

Johnson et ah. (5974) recognized 5 

stages c~f development of young southern pine 

stands that might be reflected in non-game 

bird population response, These were: (1) 

the devegetated area produced by site preparation, (2) seedling stage, (3) sapling or 

brush stage, (4) croka closure to an age of 

about i5 years, and (5) 15 years to the end 

of the rotation, Length of time in each of 

these stages will of course be affected by 

site conditions, nethod of planting, species 

treatments such as fertilization, precomercia1 thinning, and prescribed burning, 

As previously pointed out, the site preparation stage has rnini'mdm capacity to support 

bird populations, but in the seedling stage 

the habitat begins to recover, Stransky et al. 

(1976) reporred that a loblolly pine regeneration area that had been chopped and burned was 

rich in species of seed producing grasses, composites, legumes, vines and shrubs at the end 

of the first growing season foLiowing treatment, This same type of response could be expected on slash pine. regeneration sites where 

the soils are moderately well dr~ined, Longleaf regeneratian sites are ty~ically drier 

and the vegetation response will usually be 

less rapid, 
The nature of the habitat in the seedling stage will be determined to some extent 

by the method of regeneration, In addition 

the stocking rates will influence the length 

of time until crown closure and the severity 

of competition with herbs, shrubs, vines and 

hardwood seedlings which add to habitat complexity. Under favorable conditions dense 

stands of regeneration can be established by 

clearcutting, seedtree, shelterwood and direct seeding methods. The removal of overstory residuals in the seedtree and shelterwood method will thin these stands to some 

extent by mechanical damage incurred during 

logging and provide growing space for plants 

other than pines. In these stands beingnaturally regenerated usually only prescribed 

burning will have been done for site preparation and the mix of herbs, shrubs and 

hardwood seedlings with the pine seedlings 

will create a substantially complex habitat. 

In direct seeding, however, the site will 

usually have been devegetated and the seedbed prepared by drastic disturbance. In 

this situation, particularly where seedling 

establishment is highly successful, the habitat will rapidly approach the minimum complexity of a monoculture. 

Natural regeneration and direct seeding 

are more common in longleaf pine than in 

slash. Slash pine is most frequently regenerated by planting. Again the rate of seedling stocking will be important particularly 

for determining the character of the sapling 

or brush stage. The U. S. Forest Service 

Wildlife Habitat Management Handbook for the 

Southern Region (USDA 1971) recommends planting on a 10 ft. x 10 ft, or 10 ft. q 12 ft. 

spacing to encourage understory development. 

Hawley (1965) presented data showing that 

basal area in slash pine planted on a 6 ft. 

x 6 ft, spacing at age 9 years exceeded the 

10 ft. x 10 ft. spacing by a factor of 1.6. 

This would be quite an expensive trade-off 

in timber value for bird habitat. Possibly 

more reasonable initial spacing might be 

6 ft. x 8 ft. or 5 ft. x 10 ft, where Hawley 

(op. cit.) reported basal areas to be 93 percent and 83 percent respectively of the 6 ft. 

x 6 ft, spacing and still provide space for 

understory development. 

The early seedling stage in both longleaf and slash pine may provide important 

habitat for grassland users especially on 

site prepared areas, lqithin the range of 

these timber types, summer use will probably 

be minimal. Summer temperatures on these 

areas are extremely high and the vegetative 

cover that can serve as shelter is largely 

missing. Some migrants and winter flocks of 

sparrows and juncos will use these sites 

heavily, however . 

The length of time that the stand will 

be in the seedling stage will differ greatly 

between longleaf and slash, Slash pine may 

be in the sapling stage in 3 to 4 years and 

the stand may close by 5 to 6 years of age. 

Longleaf on the other hand may remain in the 

seedling stage up to 10 years depending upon 

the severity of brown spot needle blight. During this time the stand may be repeatedly prescribed burned on a 3-year schedule, the 

impact of which will be to maintain the stand 

in an "old field" type of succession. Grassland and shrub vegetation users will be accommodated in this situation. 

Fire cannot be used in the seedling or 

sapling stage of slash pine development until 

the trees are 10 to 15 feet high (Cooper 1965). 

Neither can it be used in longleaf pine after 

leader growth begins until the stems are at 

least 10 feet high. The absence of fire in 

the habitat hastens the change from a primarily 

herbaceous community to a primarily woody plant 

system which largely eliminates niche space for 

grassland users. During the sapling stage however when the shrub and hardwood seedling component of the habitat is building and prior to 

crown closure by the pines, the community is 

quite complex and will provide for a largepopulation of non-game birds. In short rotation 

systems, the bird niche diversity and niche 

space is at the highest point that will occur 

in the life of the stand in intensive management situations. The duration of this high 

carrying capacity situation is probably no 

more than 3 years in slash pine on moist sites 

where understory development is rapid although 

it is offset by rapid crown closure. In longleaf stands it may last for 6 to 8 years or 

more due to the growth habit of longleaf where 

branching is not heavy and although the saplings are putting on considerable height 

growth there remains a great deal of growing 

space for shrubs and hardwoods. The best longleaf sites will support a considerably complex 

habitat in this stage but on drier areas shrub 

and hardwood gr~wth vill be slow and herbaceous 

plants will make up a considerable portion of 

the vegetation. 

Closing of the stand is accompanied by a 

drastic decrease in bird niche diversity and 

carrying capacity. The plant community approaches the pure monoculture where habitat 

complexity is minirnurr,. During this stage most 

of the bird activity will occur along the 

edges of the stand, Brown Thrashers, thrushes 

and Towhees will frequent these stands but the 

 no^-game bird species diversity will be considerably lower than in the previous stage. 

The change will usually be more dramatic in 

slash pine than in longleaf, 
From stand closure to age 15 to 20 years 

the stand remains relatively simple. Slash 

pine being managed on a short rotation will 

be dense with Little to no understory. Longleaf pine will be somewhat more complex 

with degree of complexity depending upon 

frequency of prescribed fire. 

At 15 to 20 years the amount of light 

reaching the forest floor should increase 

as some expression of dominance creates irregularities in the canopy. Light penetration enhances understory development although the new population of plants may be 

sparse and unthrifty. At the very best 

there is some additional complexity to add 

small but new niches. The newest and expanding niche at this stage however is the 

availability of tree trunks for bole feeders 

such as the Downy, Hairy, and Red-cockaded 

Woodpeckers, and Red-breasted, Whitebreasted, and Brom-Headed Nuthatches. In 

addition, Mourning doves will nest in stands 

in this stage of development. 

From 15 to 20 years of age until commercial thinning or the end of rotation in 

short rotation stands, the complexityof the 

bird niche diversity and carrying capacity 

increase slowly. At about age 35 in short 

rotation management the stand will be harvested and regenerated. In long rotation 

stands, thinnings and natural mortality 

will begin to open up the stand enough to 

allow understory development and increase 

complexity. As the understory develops, 

niche diversity and carrying capacitywill 

increase to around 50 to 60 years of age 

depending upon site conditions and frequency of prescribed fire. 

Walker (1962) indicated that final harvest of longleaf may occur at age 70 in long 

rotation but may go to 120 years. The most 

significant new feature in old growth stands 

is the presence of large dead treesresulting 

largely from lightning strikes and insect 

attack. These are extremely important habitat features to the non-game bird population. Size of the carrying capacity is dependent on the density of dead trees. There 

are 17 cavity nesters that use dead trees in 

the longleaf-slash pine type. These species 

are most abundant in old growth stands and 

least abundant in young stands devoid of 

standing dead trees. 

INTERMEDIATE TREATMENTS 

Fertilization 

Fertilization is a treatment used more 

in slash pine than in longleaf and primarily 

in young stands under intensive management. 

Phosphorus and a combination of phosphorus 

and nitrogen are the most used elements. They 

have been applied at two stages, the seedling 

stage and again at about age 25 to 30. Fertilization has two effects in the seedling stage. 

First, and most importantly when P;i is used,the 

herbaceous plant growth is stimulated. This 

adds complexity to the habitat but more importantly it probably adds to bird carrying capacity. Second the fertilization effect reduces the amount of time in the seedling stage 

and shortens the length of tine until crown 

closure. The effect is to reduce the period 

of time in which a short rotation stand is at 

its highest carrying capacity for birds but 

probably raises the carrying capacity during 

this time. 

If fertilization is done again when the 

stand is 25 to 30 years old, it is carried out 

in combination with thinning. The most important effect on birds will be on understory development. The interaction of increased nutrir 

ents and light should greatly enhance growth 

of tolerant shrubs and hardwoods and improve 

the quality of the habitat. 

Prescribed Fire 

Management of longleaf and slash pine is 

at least impractical and probably impossible 

without prescribed fire. In both species the 

need for control of hazardous fuel build-up, 

control of understory development, and seedbed preparation exists. As previouslypointed 

out, periodic fire in longleaf pine in the 

grass stage is necessary for brown-spot needle 

blight control before leader growth can begin. 

Burning on about a 3-year schedule during this 

period suppresses shrub and hardwood development and enhances herbaceous growth. Grassland species benefit but where shrubs are allowed to encroach, niches are added for the 

shrubland species. 

Fire must be kept out of seedling stage 

slash pine and the small sapling stage of both 

slash and longleaf. After this period, fire 

must be used for hazardous fuel and hardwood 

control. It has three impacts on the bird habitat: (1) control of the understory keeps niche 

diversity low, (2) reduction of the litter 

(rough) exposes seeds that would not otherwise 

be available for forage, and (3) destruction 

of dead trees which eliminates niches for dead 

tree feeders and cavity nesters. 

There are 3 considerations in prescribing 

fire that will determine the nature of the impact. First, the season of burning is an important criterion determining impact on the 

understory as well as direct impact on the 
birds. Burning during the spring and summer 

months may destroy nests of ground nesting 

birds as well as those of birds nesting in 

low understory. Spring and summer fires 

are more effective in killing understory 

than fall and winter burns, To minimize 

adverse impact the objective should be to 

control understory development rather than 

eradicate it. 

Second, frequency of fire is the most 

important criterion determining structureof 

the stand understory. Fire is recommended 

in southern pine mansgement on a 3 to 5 

year schedule. Burning more often than 

every 3 years tends toward eradication of 

shrubs and hardwoods and greatly lowers 

bird niche diversity. As previously pointed 

out, understory control is tolerable in nongame bird habitat but eradication has a serious adverse effect. Where the fuel buildup can be tolerated, burning on a 5-year 

schedule is preferable to a 3-year schedule. 

And third, the type of fire used has 

bearing on the nature of the effect. Back 

fires (burning against the wind)move slower, 

remain at the base of the hardwood stems 

longer, and are likely to produce more hardwood control than other types. Even though 

the kill may be greater, the back fire does 

not blacken, defoliate, and "de-branch" the 

shrubs and hardwoods and thereby have the 

immediate dramatic impact of headfires (burning with the wind) or flank fires (burning 

parallel to the wind). Headfires and flank 

fires are used primarily for fuel control 

and can only be used when the crown of the 

pines are far above the ground. Backfires, 

however, can be used in young stands. 

In the case of the Red-cockaded Woodpecker, much has been made of the need for 

frequent fires to maintain open stands for 

foraging by the bird. Based on 24,300 observations on 6 separate clans and taken 

over the period of one year, we have found 

that the bird uses Longleaf an3 loblolly 

stands with well developed understories at 

least with the relative frequency of stands 

with no understory. To maintain simple 

structured stands for the Red-cockaded is, 

in our opinion, not necessary and is tothe 

detriment of a more species rich noc-game 

bird population. 

The numbers of standing dead trees in 

the forest is affected by the frequency and 

intensity of fire, These trees are important 

as a foraging medium for woodpeckers and to 

provide nest space availability for cavity 

nesters. Frequent fires will destroy dead 

pines long before they would fall from 

natural decay. In addition charring of the bole 

surface and burning out cavities tends to detract from their usability. 

Precommercial. thin~ings in slash pine have 

been recommended by Jones (1974) and Langdon 

and Bennett (1976). It is recommended thac 

precommercial thinning be carried out at least 

by age 5 and be done whenever stand density exceeds 1000 stems per acre. Numbers of residuals 

would depend upon product goals, Jories (op. eit .) 

recommended mechanized thinning by cutting 

swaths 8 to 10 feet wide and Leaving strips 4 

to 8 feet wide. Such a disturbance to the 

stand would of course add to its complexity in 

vegetation structure and species composition. 

It will change a stand in which the crowns 

have closed and carrying capacity dropped to 

a minimum to habitat favorable to a largevariety of non-game bird species, 

Commercial thinnings that may be used in 

slash and longleaf pine are of four general 

types: (I) low, (2) crown, (3) selection, and 

(4) mechanical. Smith (1962:92) gave generalized curves describing the distribution of 

DBH classes that would be removed in each of 

these procedures (fig. 1). By assuming that 

crown sizes are roughly correlated with DBH 

one can get some idea of the relative amounts 

of understory response. 

The low thinning where trees with crowns 

in suppressed or intermediate classes are removed may change the light regime at the forest floor to some extent but not very much. 

Understory vegetation may be slightly stimulated but not enough to significantly change 

niche diversity although carrying capacity 

may be improved to some extent. 

The crown thinning may remove trees in 

all crown classes but it will concentrate on 

dominants and codominants. This will have a 

major impact on the understory. Eiche diversity and carrying capacity will be enlarged. 

Crown thinning will more ofteri be carriec out 

in natural stands than planted stands and is 

usualLy the first thinning tc be 2pplied. 

Selection thinning may be dons at any 

time but concentrates on the removal of doninants. Again, since the larger crowns are being removed, a considerable response can be 

expected in the understory giving added complexity to the stand. 

Mechanical thinning is mostly applied to 

plantations where rows of trees can be removed 

without regard to the quality or potential or 
SELECTION MECHANICAL 

Figure 1.--Distribution of diameter classes that would be removed by 

4 methods of thinning (after Smith 1962:92j. 
residual stems, It is usually a pulpwood 

cut ~ade at a time in the life of the stand 

when a light understory is just beginning to 

develop. The treatment raises the stand 

from relatively nonproductive conditions in 

terms of patential to aceormodate birds to 

one which my be very productive. 

Sanitation and Salvage Cutting 

The last silviculturaL treatment to be 

discussed is sanitation and salvage cutting. 

These are the Least intensive procedures 

and yet have one 3f the most important impacts on non-game bird populations. Lightning and insect attack are the primary 

causes for slash and longleaf pine mortality. 

Cavity nesting species, of which there are 

17 in the longleaf-slash pine type (Table 11, 

are almost totally dependent on this mortality for nexting opportunities. Where 

salvage operations remove wounded trees before they decay to a state usable by birds, 

the cavity nesters are largely missing in 

the non-game bird population. 

Table 1,--Cavity nesting species that use 

dead trees in the longleaf-slash pine type. 

and/or precluding niche development. Long rotation management provides for longer periods 

of time when the stand may accommodate Large 

bird populations than does short rotation 

management. Cutting methods fornatural regeneration and thinning practices enhance stand 

complexity and provide for a wide variety of 

birds, Precomercial thinning creates highly 

productive habitat in what was previously a 

simple nonoculture. Prescribed burning is a 

necessary practice in longleaf-slash pine 

management, but when carried out with the objective of eradicating understory rather than 

controlling it, the practice has a highly 

detrimental effect on non-game bird habitat. 

Furthermore the loss of dead standing trees 

during prescribed burning can have a dramatic 

impact on the cavity nesters. Cavity nesters 

should be managed for by tempering intensity 

of sanitation and salvage cutting. 

LITEMTURE CITED 

Bennett, F. A. 

1965. Thinning slash pine. Pp. 111-118. 

In: W. G. Wahlenberg (Ed.) A Guide to 

Loblolly and Slash Pine PlantationManagement in Southeastern USA. Georgia Forest 

Research Council. Report No. 14. 360 p. 

American KestraL 

Screech Owl 

Barred Otjl 

Yellow-shafted Flicker 

Pileated Woodpecker 

Red-bellied Woodpecker 

Hairy Woodpecker 

Domy Woodpecker 

Eastern Bluebird 

Great-crested 

Flycatcher 

Yellow-bellied 

Flycatcher 

Carolina Chickadee 

Tufted Titmouse 

White-breasted 

Nuthatch 

Red-breasted Nuthatch 

Brown-headed Nuthatch 

Carolina Wren 

Bent, A. C. 

1937. Life histories of North American 

birds of prey. Part I.. Smithsonian Institution. United States National Museum. 

Bull. 167. 409 p. 

Bent, A. C. 

1938, Life histories of North American birds 

of prey. Part 11. Smithsonian Institution. United States National Museum. 

Bull. 170. 482 p. 

Dead pine trees may stand for 5 to 15 

years and be heavily used for 80 to 90 percent of this time. A dead tree stocking of 

one stem per acre would be highly desirable. 

In addicion planning for a population of 

dead trees should be made such that salvage 

operations do noc prevent replacements made 

necessary by Losses to prescribed fire and 

decay. 

Bent, A. C. 

1939. Life histories of North ilmericanwoodpeckers. Smithsonian Institution. United 

States National Museum. Bull. 174. 334 p. 

Bent, A. C. 

1940. Life histories of NorthAmerican cuckoos, goatsuckers, hummingbirds, and their 

allies. Smithsonian Institution. United 

States National Yuseum. Bull. 176. 506 p. 

The silvicultural practices in the longleaf-slash pine type that tend to decrease 

stand complexity by eradicating understory, 

destroying dead trees, and generally promating a pine :sonoculture with a bare forest floor are deleterious to non-game bird 

populations, This is done 'by destroying 

Sent, A. C. 

1942. Life histories of North American flycatchers, larks, swallows, and their alLies. Smithsonian Institution. United 

States National Museum. Bull, 179. 555 p. 

Bent, A. C. 

1946. Life histories of North American jays, 

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1948. Life histories of North American nuthatches, wrens, thrashers, and their allies. Smithsonian Institution. United 

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1953. Life histories of North American 

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1965. Prescribed burning and control of 

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1971. Distribution of certain birds in 

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1975. A Field Guide to Birds' Nests in the 

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1965, Initial spacing of slash pine. Pp. 

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1974. Wildlife in young pine plantation, Pp. 

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1956. Breeding bird populations in relation 

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1975. Precommercial thinning for slash and 

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42:594-598. 

MacArthur, R.H., J.W. MacArthur and J. Preer. 

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1950. Bird populations of the Highlands 

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plant succession and avian invasion. 

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Roth, R. R. 

1976. Spatial heterogeneity and bird species diversity. Ecology 57~773-782. 

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1936. Ecology of the birds of Quaker Run 

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bird populations in north-western 

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1962. The Practice of Silviculture. 

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Importance to songbirds. Stephen F. 

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FSH 2609.23R. 189 p. 

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States. Forest Service. Forest Re-. 

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Walker, L. C. 

1962. The Coastal Plain southern pine 

region. Pp. 246-295. In: 3. W. Barrett 

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York. 610 p. 
Bird Communities Associated With Succession and Management 

of Loblolly-Shortleaf Pine Forests 

r/ Joseph M, Meyers and A. Sydney JohnsonAbstract.--Priblished data from 17 winter and 32 s 

bird censuses were used to determine changes in bird species 

composition, richness, and density in relation to plant 

succession and forest management in loblolly-shortleaf pine 

forests. Recornmendations for habitat managment are offered, 

INTRODUCTION 

Birds are a major faunal component of our 

forests. They are becoming a more valued 

recreational resource as man modifies and 

eliminates forests (Payne and DeGraaf 1973)- 

Birds are useful as indicators of hazardous 

cnviromental conditions; the-cases of DDT and 

PCB's provide good examples of how bird popufations can forewarn us of potential hazards 

of pollutants. Bird populations, because of 

their great mobility, are important seed 

dispersers and vectors of diseases (Shugart 

vet al, 1975) . However, there are few data 

relating to the ecological roles of birds in 

&orest ecosystems. Research on this subject 

ias been emphasized for less than two decades 

and has established only a basic understanding 

cf forest avifama. 

Likewise, forest management for birds 

other than a few gme species has received 

serious consideration only recently. In the 

past wildlife management was synonymous with 

game management, "Nongme" management-- 

nnnagement of wildlife other than game and 

,~mercially important species--is largely a 

product of increased environmental awareness 

in the 1370's, But, the term "nongame" is a 

vague one that does not describe animals; it 

only tells us what they are not. Wildlife 

management should not be approached on game 

and nongme terns but on a holistic basis 

with consideration for entire plant and 

animal comunities, The purpose of this 

paper is to describe the possible bird commmities that are associated with successional 

stages of Loblolly-shortleaf pine (Pinus 

1/ Meyers is Research Assistant, School of 

Forest Resources, University of Georgia, and 

Johnson is Associate Director, Institute of 

Natural Resources, and Associate Professor 

School of Forest Resources, University of 

Georgia, Athens. 

-- taeda-P. echinata) forests and how they can be 

managed in ways compatible with sound management of other forest resources. 

THE LOBLOLLY-SHORTLEW PINE PLANT COMMUNITY 

The loblolly-shortleaf pine forest type, 

a major component of the southeastern forest 

(fig. 11, is widely distributed throughout 

the Southeast in both the Piedmont and Coastal 

Plain provinces, except in Florida and 

Tennessee. The loblolly-shortleaf type includes 

forests composed of 50 percent or more loblolly 

pine, shortleaf pine, and other southern pines, 

except longleaf (P. palustris) and slash (I?-. 

elliottii). Loblolly and shortleaf pines occur 

separately or in combination and are commonly 

associated with oak (Quercus spp.), hickory 

(Carya spp.), and sweetgum (Liquidambar 

styraciflua) (U. S. Forest Service 1969). 

Loblolly-shortleaf forest is a subclimax 

or developmental stage in a successional sere 

leading to oak-hickory climax. Oak-hickory and 

other hardwoods formed the original cover of 

much of the region (Oosting 1942, Wahlenberg 

1949). But, in the Coastal Plain large areas 

were forested with subclimax pines. Fire, and 

agriculture practiced by the Indians were 

important factors in arresting succession. 

Even in the Piedmont, extensive pine forests 

occurred on dry upland sites on gray soils 

derived from granite, gneiss, sandstone, or 

slate; hardwoods dominated sites on red clay 

loams {Pinchot and Ashe 1897, Harper 1943, 

Nelson 1957, Brender 1974). 

Land Use History 

Beginning late in the 18th Century, a 

wave of settlement moved southwestward from 

Virginia and North Carolina, and in little over 

a half century the entire region was settled by 

subsistence farmers and planters. Most of the 

loblolly-shortleaf type is in the old Cotton 
Figure 1.--Loblolly-shortleaf pine forest of the southeastern United States. 

(U. S. Forest Service 1969) , 

Belt where intensive agriculture and the 

nature of the climate, soils and topography 

combined to produce severe soil erosion and 

loss of fertility. There were several periods 

of land abandonment, the most recent and most 

important coinciding with the economic depression and invasion by the cotton boll weevil 

(Anthonomus grandis) in the 1920's. Abandoned 

fields were invaded by loblolly pine and, on 

drier sites, shortleaf pine. Virtually all of 

the natural stands of loblolly-shortleaf 

remaining today developed on abandoned agricultural fields. Most stands established 

before 1945 have been heavily cut. Some have 

regenerated naturally; others have been 

planted and are under management for pulpwood. 

Secondary Succession 

Old Field Stage 

On Piedmont uplands the first sera1 stage 

is a succession of herbs and grasses through 

the fifth -year. Crabgrass (Digitaria 

sanguinalis) and horseweed (Erigeron canadense) 

dominate the first growing season following 

cultivation in the Piedmont, and young plant 

growth, less than 0.3 m, is present during the 

first bird breeding season. Taller growth up 

to 2 m develops by the end of the first year. 

In the second year the dominant species are 

aster (Aster pilosus) and ragweed (Ambrosia 

artemisiifolia). Broomsedge (Andropogon spp.) 

attains dominance in the third year and persists 

until shaded out by pines, which begin to appear 

in the third year. Various shrubs (e.g. Rubus, 

-- Rhus, Prunus) and small deciduous trees also 

occur with the pines until canopy closure 

(Oosting 1942, Johnston and Odum 1956). 

Elsewhere in the loblolly-shortleaf type, 

succession is less uniform and less predictable. 

This is especially true of the early stages 

where species composition of invading annuals 

and perennial grasses my vary with structure 

and fertility of soils, drainage, and previous 

land use. Soil fertility may also affect 

species composition and growth rates of trees. 

Pine Forest Stage 

By the 11th year pine dominates well 

seeded areas. Trees are 2.4-4.6 m tall with a 

broomsedge and shrub groundstory (Oosting 1942). 

Tree density is dependent on ample seed 

stocking, but differences in density diminish 

as stands age; dense pine thickets thin naturally on fertile sites and open-growth stands 

form closed canopies (Brender 1973). 
Canopy closure usually eccurs between 10 vertical strata of vegetation--groundstory 

and 20 years. Only small patches of ground- (0-3 m) , understory (3 to 10 m) , and overstory 

story plants exist in dense stands of this age (over 10 rn), Hortizontal clmping (patchiness) 

class; there is essentially only one stratum is more prevalent in mixed stands. Lightning, 

of vegetation- More open, natural pine stands red heart disease, and the southern pine beetle 

have hardwoods sf tree size which slowly but fDendroctonus frontalis) cause small openings 

steadily increase (Oosting 1942) . and thereby create uneven age classes. Snags 

A shade tolerant hardwood understory 

appears in the later sera1 stages of the pine 

forest (fig. 21, The decline in pine density 

is accompanied by a steady increase in density 

of hardwoods, Natural pine stands 60 to 100 

years old have a well developed hardwood 

understory and gromd cover. 

STAND AGE 

Figure 2,--Piedmont forest succession from 

Poblolly-shortleaf pine to oak-hickory 

hardwoods. (redrawn from Oosting 1942) . 

Mixed Pine-Hardwcod Stage 

During the transition from pine to hardwood forest, habitat conditions are quite 

diverse. for this disc:ssion we define mixed 

pine-hardwoods as stands with greater than 10 

percent and Less than 50 percent loblolly, 

shortleaf, and other southern pines, except 

slash and longleaf. Mixed stands usually 

occur in age classes between 80 and 120 years 

(fig, 2); however, younger stands can have a 

substantial ammt of hardwoods depending on 

site conditions, Brender (1973) states that 

on poor sites, red heart disease (caused by 

-- Fomes pini) becomes established earlier, and 

pine stands begin to break up at age 60, 

Also, when pines are cut, many stands revert 

to hardwoods (Wahlenberg 1949); in the absence 

of fire, root stock of hardwoods in the understory is released when pines are removed. 

~ixed pine-hardwoods develop three 

(dead standing trees) become more abundant as 

the pine forest is replaced by mature oakhickory forest, 

Me divided the avian cornunity into the 

two major populations--winter populations and 

smer breeding populations. More data have 

been accumulated on breeding bird populations. 

Data collected in spring and smer are more 

reliable thanthosecollected during winter or 

migratory seasons because of breeding season 

territoriality in most bird species. Large 

flocks of winter foragers or migrants complicate studies at other times of the year. 

Statistical differences in non-breeding bird 

studies are difficult to detect because of high 

variances or low sampling effort. 

For this review we analyzed winter bird 

populations from 17 census locations throughout the Southeast (table 1). These censuses 

include from l to 10 years of data and range 

through the succession of loblolly-shortleaf 

pine to mature oak-hickory forests. We also 

analyzed smer breeding bird communities from 

31 census locations with 1 to 16 years of data 

(table 2) . 

Temporal Patterns 

In the eastern United States a large proportion of the bird species are migratory. 

Some species migrate to the Southeast, while 

other species cross the Gulf of Mexico and 

spend the winter months in the Neotropics. 

There also are resident or sedentary species, 

such as the Carolina Chickadee (Parus 

carolinensis) 2/ and Tufted Titmouse (g. 

bicolor) . With migration, bird communities 

change seasonally. During the spring and 

summer, breeding territories are established 

and individual breeding birds are relatively 

sedentaq. However, in the winter months interspecific flocks are common in most habitats. 

For example Kinglets (Regulus spp.), a northern 

coniferous forest breeder, are abundant winter 

residents in the southeastern forest and 

usually are found in pine forests with large 

groups of chickadees and titmice. 

2/ All common names are those standardized 

and listed with scientific names by the American 

Ornithologists~nion check-list committee 

(American Ornithologists' Union 1957, 1973, 

1976) . 
Table 1.--locations and habitat data for winter bird population censuses of 

loblolly-shortleaf pine comunities. 

Percent Stand Years 

Census Plot f tad pine of 

No. Location size type overstory age&/ data Source- 2 / 

pine 7 yrs. 

f 60%) 

6 

2 0 

".35 

'3J3 5 

3 0 

45 

mature 

mature 

Livingston Par., La. 12 

Livingston Par., La. 12 

Prof f il, \?a. 18 

El Dorado, Ark. 5 

Pine Bluff, Ark. 22 

Livingston Par., 31ja. 12 

El Dorado, Ark. - 9 

Natchitoches Par., La. 9 

El Dorado, Ark. 9 

pine 

pine 

pine 

pine 

mixed 

pine 

pine 

pine 

mixed 

Noble and Hamilton 1976 

Noble and Hamilton 1976 

AE;"N 2-8(3) 

WN 15-16(3) 

AFN 10(3) 

AB 28(3) 

AFN 7-1213) 

AB 25-28(3) 

mature AFN 5-8,10-11(3) 

(60%) 

North Wilksboro, N-c .4/ 16 mixed mature AFN 18-19,21,23-24; 

AB 25-26? 29 (3) ,30 (6) 

AFN 18-24; 

AB 25-27(3) 

AFN 24 (3) 

AFN 24(3) 

Savannah, Ga . 10 mixed mature 

Moulton, 5/ A1a.- 2 0 

Raleigh, N.C. 5 

mixed 

oakhickory 

oakhickory 

S mixed 

hdwd . oakhickory 

mature 

mature 

mature AFN 24 (3) 

Livingston Par., La. 12 mature Noble and Hamilton 1976 

McLean, Va. 11 mature 

Mature pine stands are >45 years old; mature mixed and oak-hickory stands are 

>75 years old. 

AFN = Audubon Field Notes, AB = American Birds;volume and number are listed with each 

citation - "Winter Bird Population Studies." 

1' 75% is under forest management, 25% of the area was logged for pine in 1949 (2 years 

before the date of census). 

4/ White pine - shortleaf pine and oak community in the mountains. 

Large flocks of Common Grackles and blackbirds were excluded. 
Table 2.--Loeations and habitat data for breeding bird censuses of loblolly-shortleaf pine 

forest stands and other pine-hardwood stands, 

Percent Stand Years 

Census Plot Stand1/ pine of 

No. Location size type - overstory agey data 3/ Source - 

Livingston Par., La. 

Warner Robbins, Ga, 

Raleigh, N.G. 

Raleigh, N.G. 

Durham, N.C. 

Oakland, Md. 

Durham, N .C. 

Livingston Par., La. 

Romney, W.Va. 

5/ Durham, N.C. - Snowhill, Md. 

Pine Bluff , Ark. 

Athens, Ga. 

Athens, GA. 

Warner Robbins, Ga. 

Durham, N.C. 

El Dorado, Ark. 

Southport, N.C. 

Savannah, Ga. 

Chapel Rill, N.C. 

Livingston Par., La. 

Durham, N.C. 

El Dorado, Ark 6/ Savannah, Ga. - 

Romney, W.Va. 

Fairf ield, Ala . 7 / El Dorado, Ark. - 8/ N. Wilksboro, N.C. - 

Chapel Hill, N.C. 

pine 

pine 

pine 

pine 

mixed 

pine 

pine 

pine 

pine 

pine 

pine 

mixed 

pine 

pine 

mixed 

pine 

pine 

mixed 

pine 

pine 

pine 

pine 

mixed 

mixed 

mixed 

mixed 

mixed 

mixed 

beechti yr. 

q~ 7 

Tt.7 

%9 

1-10 

10-20 

10-20 

20 

20 

20-30 

25-30 

<30 

"J35 

3 3 

s35 

30-40 

3 5 

35-40 

40-45 

30-60 

45-46 

70-80 

mature 

mature 

mature? 

mature 

mature 

mature 

mature 

NI-I 1976 4/ 

WN 6(6) 

WN 21 (6) 

AFN 23(6) 

AFN 20(6) 

AFN 3(6) z1;;L6i/ 

AFN 21(6) 

AFN 20(6) 

AF'N 2(6) 

AFN 9 (6) 

AFN l(6) 

AFN 17(6) 

AFN 7 (6) 

AFN 20(6) 

AE'N 14-15(6) 

AB 27 (6) ,31(1) 

AF'N 19-21(6) 

AFN 20(6 h/ NH 1976 - ; AB 28 (6) 

AFN 20(6) 

AFN 11 (6) 

AFN 17 , 19-24 (6) ; 

AB 25-27(6) 

AFN 21 (6) 

AE'N 3-4 (6) 

AFN ll(6) 

AFN 8-9,11,14-24(6); 

AB 25-26,29 (6) 

AB 27-28(6) 

maple 

29 LivingstonPar.,La. 12 S. mixed 6 mature 4/ 1 NH 1976 - hdwd . 30 Durham, N.C. 11 oak- <5 mature 1 AF'N 20(6) 

hickory 

31 Berkley Spr., W.Va. 6 oak- 0 mature 1 AE'N 11(6) 

hickory 

32 Athens,Ga. 9 oak- "J5 mature 1 AFN l(6) 

hickory -- -, - 

L/ Pine = loblolly-shortleaf pine; mixed = pine and hardwoods. 

Mature pine stands are >45 years old; mature, mixad, oak-hickory, and beech-maple 

stands are >75 years old. 

AFN = Audubon Field Notes, AB = American Birds; volume and number are listed with each 

citation; see Breeding Bird Census. 

4' Noble and Hamilton 1976. 

2 i' Edge effect accounted for 4 of 14 species and 220 individuals/km . 

6' Slash and longleaf pine are 28% of the overstory, while loblolly is 4%. 

1' Some recent logging was done on the plot. 

'/ White pine-shortleaf pine and oak community in the mountains. 
Temperature and Latitudinal Gradients 

During the winter, the number of bird 

species (richness) is closely related to the 

number of frost-free days (Bock and Lepthien 

1974, Trmer 1974a). The mild and fairly 

stable winter climate of the Southeast is 

apparently important to many bird species that 

do not tolerate harsh northern winters, 

Climate does not seem to affect species numbers 

in areas with more than 245 frost-free days. 

Because of this relationship, more bird species 

should be present in pine forests in Louisiana 

than in Virginia or North Carolina. Also, 

more species should be present in milder 

coastal areas than interior habitats. Tramer 

(1974b) states that temperate zone winter 

ranges appear to be regulated by the effects 

of climate on food supply. 

In general breeding bird species richness 

is inversely related to latitude; however, 

breeding species richness is less in the southeastern than in the northeastern United States. 

Various explanations for this were presented 

by Tramer (1974b). 

Winter Bird Community 

Successional Trends 

Quay (1947) completed a detailed study of 

winter bird populations in an upland plant 

sere near Raleigh, North Carolina. His study 

was conducted during one winter, and density 

estimates within seral stages may reflect 

favorable or unfavorable climate that year. 

However, his study does delineate changes in 

winter bird populations associated with plant 

cornunities in that specific region. 

Data on winter bird populations from the 

17 census locations (table 1) were analyzed 

for changes in species richness and density 

with changes in the plant community (figs. 3, 

4). In most censuses (source AF'N, AB--see 

table 1) it was not possible to calculate the 

Shannon Index for species diversity (MacArthur 

and MacArthur 1961) because data tabulation 

was in rounded whole numbers (means) and 

included symbols (+) for uncommon species. 

Species richness in winter populations 

increased in the early seral stage from 7-15 

species in old fields to 27-30 species in 

young open-canopy pine stands with patches of 

older trees or open wet areas. However, very 

few data were available for this seral stage, 

and the apparent trend could be due in part 

to temperature gradients. Quay's (1947) study 

showed a slight decrease in species richness 

from bare ground to herb and broomsedge-pine 

habitats (fig. 3). 

Census data for stands after canopy 

closure indicate a decrease in species richness, 

which is not reversed until age 35 (fig. 3). 

Dickson and Segelquist (1978) found stands 

of dense pine saplings (age 15) practically 

devoid of birds; younger and older stands 

had substantially more species and higher 

densities. Bird densities (fig. 4) also 

follow the same trend in the few censuses 

available for these seral stages. In 

Louisiana winter bird densities decreased 50 

percent (fig. 4, table 1) from a 7-year-old 

pine stand to a closed canopy stand (age 201; 

however, a 45-year-old pine stand showed an 

additional decrease in density from the 20- 

year-old stand (Yoble and Hamilton 1976). 

These data contradict studies by Quay (19471 

and Dickson and Segelquist (1978). Apparently 

reduced winter bird species and density in the 

45-year-old stand was the result of annual 

burning, which eliminates the lower vegetative 

stratum (Noble and Hamilton 1976). 

From mature pine to mixed pine-hardwood 

seral stages there is considerably higher 

density and species richness with the increase 

in percent hardwoods (figs. 3, 4). Decreases 

in density and species richness in mature 

stages of forest succession are apparent in 

colder, more northerly environments, e.g. 

North Carolina and Virginia (figs. 3, 4). This 

difference possibly results from greater availability of food in the southern latitudes 

(Tramer 1374b). 

Species Composition 

Fringillids (sparrows, towhees, goldfinches, etc.) are the major group of winter 

birds in young seral stages. Savannah Sparrow 

(Passerculus sandwichensis), Field Sparrow 

(Spizella pusilla), Dark-eyed Junco (Junco 

hyemalisf , and Song Sparrow (Melospiza melodia) 

are common fringillids in old fields during the 

winter (Quay 1947, Odum and Wight 1957). Other 

common species in early stage old fields (0-5 

vears old1 are Eastern Meadowlark (Sturnella 

magna), Bobwhite (Colinus virginianus), Killdeer (Charadrius vociferus), and Mourning Dove 

(Zenaida macroura). As shrubs, vines, and 

small pines become available for cover and 

foraging, White-throated Sparrow (Zonotrichia 

albicollis), Cardinal (Cardinalis cardinalis), 

Rufous-sided Towhee (Pipilo erythrophthalmusl, 

and wrens become abundant, 

The pine or mixed pine-hardwood forest is 

used by a variety of bird groups and foraging 

guilds. Woodpeckers are common through the 

winter in forest stands of all ages but are 

most abmdant in mature stands. Golden-crowned 

and Ruby-crowned Kinglets (Regulus satrapa and 

- R. calendula) are comon to abundant in pine 

and mixed pine-hardwoods. These species breed 

in northern coniferous forests and winter in 

southern pine forests. They are commonly found 

in flocks with permanent residents, such as 

Carolina Chickadees, Tufted Titmice, and Downy 
lo@% -+ 

3ia 

6 Ark 

I -4- 

11 NC. N.C. 

hardwood 

STAND AGE 

gure 3.--The relationship of winter bird species richness with succession of loblolly-shortleaf 

pine forests. Vertical line represents the range, horizontal line the mean, hollow rectangle 

one standard deviation on either side of mean, and solid rectangle 95% confidence interval on 

either side -- - of mean. Percent pine is given above each symbol and census location and number 

below each figure. Solid triangles refer to Quay 1947. 

88% 

-t 

2 La. 

A 

age? 

39% 

6% +-- 

16 La. 

STAND AGE 

Figure 4.--The relationship of winter bird density with succession of loblolly-shortleaf pine 

forests. See figure 3 for interpretation of symbols. 
Woodpeckers (Picoides pubescens) . In most 

cases pine forests in the Piedmont loblollyshortleaf type have higher populations in 

winter than deciduous forests because of the 

addition of kinglets to the pemanent resident populations (Johnstoc and Odum l956). 

Pine warblers (Dendroica pinus), pemnent 

residents, are comon in pine stands of all 

age classes, Another parulid, the Yellowrwped Warbler (g. coronata), is abundant in 

some years in young sera1 stages, and is also 

comonly found in flocks of pe 

dents in older forest stands. 

er Breeding Bird Community 

Successional Trends 

Breeding bird habitat in the Southeast 

is grouped into four broad stages; (1) grasslands, (2) shrubland, (3) pine forest, and (4) 

hardwood forest (Johnston and Odum 1956). 

Most of our discussion will be concerned with 

the first three stages and the transition 

i.e. mixed pine-hard~?oods) from pine to oakhickory. 

Grasslands are predominant in the 

southern Piedmont and the Coastal Plain during 

the first 3 years of natural succession. Bird 

populations and species richness are low 

during this stage (figs. 5, 6). Only two or 

three species breed in this habitat in the 

Southeast. However, in the shrub and young 

pine stage a rapid increase in breeding 

density and species takes place. Shrubs add 

patches and an additional vegetative stratum 

for nesting. This increase is short-lived as 

pine canopy closure at 10-20 years eliminates 

the ground cover and understory vegetation. 

Densities decrease from 600 territorial males 

per km2 to 200-300 per km2. Breeding bird 

species also decrease about 50 percent. These 

reduced populations are common in pine stands 

from age 15 to 30 years. 

Pine tree density decreases rapidly from 

age 11 to age 34 (fig. 2). This natural thinning allows greater light penetration to the 

ground and development of understory vegetation. At stand age 35 densities and species 

of breeding birds again rapidly increase to 

values similar to those of the shrubland stage. 

Bird species richness is higher from stand age 

40 to 80 than in any younger age class 

(fig. 5). Again richness and density in the 

annually burned stand {census 20) was considerably lower (60-70 percent Less) than for 

unburned or irregularly burned plots (figs. 5, 

6). 

Mixed loblolly-shortleaf pine-hardwood 

forests are important breeding habitat for 

many species. Density and species richness in 

these stands are similar to mature hardwood 

forests. The average density of breeding pairs 

(territorial males) in mixed pine-hardwood is 

550 per km2. Approximately 20 breeding species 

(mapped territories, not visitors) are found in 

mesic pine-hardwood forest. Bottomland pinehardwood forests (census 22; figs. 5, 6) are 

higher in total density and species richness 

than drier sites. Within the loblolly-shortleaf pine type the mixed pine-hardwoods and 

mature pine stands have the highest density 

and species diversity. 

Relationships in Breeding Bird Populations 

~ensity and species richness are highly 

correlated in breeding bird communities. Note 

that the graphs of species richness (fig. 5) 

and breeding bird densities (fig. 6) are very 

similar. Increase in population density is 

caused primarily by the addition of new species 

(Tramer 1968). Territoriality would limit 

increase in density of bird species already 

present. Species diversity in breeding bird 

populations also is highly correlated with 

number of species. 

Foliage height diversity, an indirect 

measurement of the amount of leaf surface area 

present in the horizontal strata of the forest, 

is positively correlated with bird species 

diversity (MacArthur and MacArthur 1961). Roth 

(1976) shows that spatial heterogeneity or 

patchiness is also significantly correlated 

with bird species diversity. Both of these 

vegetative measurements are useful to bird 

managers as indicators of bird diversity. But 

diversity should not be the sole objective in 

bird habitat management. Densities and species 

composition and distribution should also be 

considered. 

Species Composition 

Figure 7 presents breeding bird species 

composition and densities with succession in 

loblolly-shortleaf pine stands. This list is 

not complete, but it contains the major 

breeding birds of concern to managers. Rare 

and endangered species will be discussed in a 

later section. Birds with large territories, 

such as raptors, are not well represented in 

breeding bird censuses because census techniques for breeding raptors are not compatible 

with passerine census techniques. 

Three common breeding species of the 

grassland stage in the Southeast are Bobwhite, 

Eastern Meadowlark, and Grasshopper Sparrow 

(modramus savannarum). Fall and winter 

Bobwhite populations are highest in 2-year-old 

fields in pine plantations (Brunswig and 

Johnson 1972). In unmanaged natural succession 

Bobwhite breeding populations presumably would 

be higher in 3- to 5-year-old fields than in 

managed pine stands of the same age, as management speeds up succession and shortens the 

duration of optimum breeding habitat. The 
STAND AGE 

Figure 5.--The relationship of breeding bird species richness with succession of loblollyshortleaf pine forests. Hexagon = grassland, circles = 50 to 100% pines, squares = 10 to 

49%pine, triangles = < 10% pines. Numbers on symbols refer to censuses in table 2. 

Numbers outside the symbols refer to duplicate points. Solid symbols refer to Johnston 

and Odum 1956. 

- 5 10 15 20 25 30 35 40 45 pine - hardwood 

STAND AGE hardwood 

Figure 6.--The relationship of breeding bird density with succession of loblolly-shortleaf pine 

forests. See figure 5 for interpretation of symbols, 
STAND AGE 

mixed 

mature pine- mature 0 5 10 15 20 25 30 5 4 45 pine hardwood hardwood llllllllll I I 

Broad- winged Hawk -----_ 

Bobwhite ---- 

Mourning Dove* 

Yellow- billed Cuckoo 

Common Flicker 

Pileated Woodpecker 

Red-bellied Woodpecker 

Red-cockaded Woodpecker 

Downy Woodpecker 

Great Crested Flycatcher 

Acadian Flycatcher 

Eastern Wood Peewee 

Blue jay* 

Carolina Chickadee 

Tufted Titmouse 

White- breasted Nuthatch 

Brown- headed Nuthatch 

Carolina Wren 

Gray catbird* 

~ockin~bird* 

Brown Thrasher* 

Wood Tbrush 

White-eyed Vireo 

Vellow - throated Vireo 

Red -eyed Vireo 

Black- and- white Warbler 

Northern Parula 

Yellow - tbroated Warbler 

Pine Warbler 

Prairie Warbler 

Ovenbird 

Kentucky Warbler 

Common Yellow throat 

Yellow -breasted Chat 

Hooded Warbler 

East ern Meadowlark 

Orchard Oriole* 

Common Crackle 

Scarlet Tanager 

Summer Tanager 

Cardinal 

Blue ~rosbeak* 

Indigo Bunt ing* 

Rufous - sided Towhee 

Bachman's Sparrow 

Grasshopper Sparrow 

Field Sparrow 

---- 

om- I 

* u Edgenspecies ( Johnston and Odum 1956) 

hardwoad 

Figure 7.--The approximate density of selected breeding birds in the sera1 stages of loblollyshortleaf pine and oak-hickory forests. Dashed line = < 5 pairs per 40 ha, solid line = 

> 5 < 10 pairs per 40 ha, and solid bar = > 10 pairs per 40 ha. Data from table 2 and 

Johnston and Odum 1956. 
Grasshopper Sparrow and Meadowlark are true 

grassland species and the only breeding 

species found in large uniform fields without shrubs or trees (Johnston and Odum 1956) . Two other uncomon species not presented in 

Cigure 7 are Killdeer and Horned Lark 

(Eremophila alpestris). Both of these birds 

feed and nest on essentially bare ground and 

are pioneer species in the successional 

series. Horfied Larks have been extending 

their breeding range eastward from the 

prairies (Johnston and Odm 1956). 

The shr&land habitat (age 5-15) is 

important to *'edge species," which require two 

or more plant cornunities usually of widely 

separated ages (Johnston and Odum 1956). 

These species are comon in shrubland and 

usually also comon at forest-shrub boundaries 

in older stands (fig. 7). A few other species 

are most abundant only in the shrubland stage 

and rapidly decrease in forest stands. Prairie 

Warbler (Dendroica discolor), Yellow-breasted 

Chat (Icteria virens), Indigo Bunting 

(Passerina cyanea) , White-eyed Vireo (Vireo 

griseus), Comon Yellowthroat (Geothlypis 

trichas), 2nd Field Sparrow are comon 

breeding species only in shrubland- Mourning 

Doves, an edge species, become fairly abundant 

in the latter part of the shrub stage. Edge 

and shrubland species are a major component 

of bird communities. Possibly more than 30 

to 40 percent of common breeding birds in the 

Georgia Piedmont belong to this category 

(Johnston and Odum 1956). These species are 

also some of the most widely recognized birds 

found in low density residential areas. 

By age 20 most pine stands have closed 

canopies with shrub and grass cover significantly reduced, However, in natural succession poorly seeded areas and eroded or wet 

areas often create a patchiness of habitats 

with clumps of pines interspersed with small 

openings of earlier sera1 stages. These 

openings increase the bird diversity and 

density in pine stands which otherwise would 

have low densities. 

The Pine Warbler, Brown-headed Nuthatch 

(Sitta pusilla), and rare Red-cockaded Woodpecker (Picoides borealis) are the only 

breeding birds restricted to the southern 

pine forest (Johnston and Odum 1956). Pine 

Warblers are most abundant in pure stands of 

pines, and their density decreases significantly with the invasion of hardwood species 

(fig. 7j. The uncommon Brwn-headed Nuthatch, 

a cavity nester, is generally a breeding bird 

of mature pine stands. The Red-cockaded Woodpecker breeds in mature pine stands with 

infections of red heart disease and is 

generally more comon in the Coastal Plain 

than Piedmont. 

In southeastern pine forests bird 

populations are determined mainly by the understory (Johnston and Odwn 1956). Grasses under 

mature pine forests create breeding habitat for 

Bobwhite and BachPnan's Sparrow (Airnophila 

aestivalis). Thick patches of shrubs or well 

developed understory in mature pine forests are 

good breeding habitat for the Carolina Wren 

{Thryothorus ludovicianusf , Great Crested Flycatcher (Myiarchus crinitus) S 

(Piranga rubra), Yellow-throated vireo (vireo 

flavifronsf , Eastern Wood Peewee (Contopus 

virens), Hoded Warbler (Wilsonia citrinaf , Northern Parula JParula americana), Cardinal, 

~ufous-sided Towhee, and many other less comon 

species (fig. 7 and data from sources in table 

2). Many of these species also occur in hardwood forests which usually have a well developed 

understory. 

As pine forests mature, hardwood species 

replace pines and produce a mixed pine-hardwood 

stand (fig. 2). These mixed forest types have 

highly diverse bird populations. Woodpeckers 

and other cavity nesters, such as the Carolina 

Chickadee, Tufted Titmouse, Great Crested Flycatcher, and White-breasted Nuthatch (Sitta 

carolinensis), are fairly abundant at this 

stage. Some of these species also are found in 

younger pure pine stands with dead standing 

trees (Noble and Hamilton 1976). In addition, 

many predominantly hardwood forest birds, such 

as the Broad-winged Hawk (Buteo platypterus) 

Acadian Flycatcher (Empidonax virescens) , Wood 

Thrush (Hylocichla mustelina), Red-eyed Vireo 

(Vireo olivaceus), Black-and-white Warbler 

(Nniotilta varia) , Ovenbird (Seiurus 

aurocapillus), and Scarlet Tanager (Piranga 

olivacea), begin to breed commonly in mixed 

pine-hardwood stands (fig. 7) . 

Endangered Species 

The only endangered species closely associated with upland loblolly-shortleaf pine is the 

Red-cockaded Woodpecker. Considerable research 

is being done on management of this species' 

habitat (Hooper et al. 1977, Baker 1977, 

Jackson 1977). The Red-cockaded Woodpecker 

breeds in open, mature pine stands. The nest 

trees are almost always infected with red heart 

disease. 

This woodpecker usually occurs in clans of 

2-10 birds, with only 1 pair breeding and the 

remaining birds acting as helpers. Cavities 

are almost always in mature, living pines and 

are readily identified by the glaze of white 

resin surrounding the entrance. The home range 

of a pair is 14 to 20 ha, and clans of 8 birds 

utilize up to 65 ha. 

Management of this species is achieved by 

providing suitable nest and roost trees, which 

include loblolly, shortleaf, longleaf, slash, 

and pond pines {Pinus serotina) at least 80 

years old. Stands for nest sites should have 
an average density of 110-124 stemsfha with a 

basal area of 11 to 14 m2/ha. Understory 

should be no more than 4-5 m tall and preferably less than 2 m. The exact stand size 

necessary for the preservation of the clan is 

not known, but is in the range of 14-65 ha 

(Chamberlain 1974) . 

TIMBER mAGEMENT IN RELATION TO BIRD HABITAT 

Management Trends 

Forest management trends have accelerated 

within the last 20 years. Land ownership, 

management objectives, and multiple use management are the major areas of change. For 

instance, forest industrial land holdings in 

the Georgia Piedmont increased 26 percent from 

1961 to 1969, and in 1973 20 percent of the 

Georgia Piedmont forest was managed by forest 

industries, mostly for production of pulpwood 

(Brender 1973). Management of loblollyshortleaf pine types has become more intense 

and mechanized. Rotation lengths are shorter 

with intensive management. 

Maintenance of forest stands in earlier 

successional stages by shorter rotations is 

eliminating mature pine and hardwood forests. 

One can readily recognize that compartmental 

control of a loblolly-shortleaf pine forest 

with no stands older than 35 years would 

eliminate many breeding bird species (fig. 7). 

Short rotation stands lack (1) suitable 

cavities for nests, (2) an understory nesting 

stratum, (3) high energy fruits and mast, and 

(4) deciduous foliage necessary for many songbirds (Johnson s $l-. 1975). More intensive 

management, with elimination of hardwoods by 

herbicides ox burning and row planting of 

pines, further reduces breeding habitat for 

ephemeral bird species in the grass and shrub 

stages. 

Multiple resource management is now the 

policy on most publicly owned forests, where 

a diversity of age claaes are maintained. 

Timber, water, wildlife, and recreation are 

the major resources of these forests. However, deliberate nongme bird management has 

not been widely practiced. Much of what 

happens is incidental to timber and game 

management. 

Only a few studies have been completed 

on bird populations and the effects of site 

treatments in the early stages of succession 

of pine plantations (see tables 1, 2). 

Obviously shorter rotation lengths in managed 

pine forests will produce more forest in 

early stages of succession. More research is 

needed on bird ~opulations during the first 

35 years of managed and unmanaged pine 

forests. 

Succession 1s predictable only on a macroscopic level (Margalef 1968). Many sites of 

the sare stage of succession will be phytofogically different because of past land uses, 

soil fertility, soil moisture, or microclimte. 

Local site characteristics are important when 

overall management decisions are made for songbird habitat. 

Harvest and Regeneration 

Harvest methods can greatly affect bird 

comunities. Southern pine forests generally 

are managed in even-aged stands, harvested by 

clear cutting, seed-tree, or shelterwood 

cutting. Much of the literature on the effects 

of even-aged timber management on bird populations concerns clearcutting. Clearcutting 

with intensive site preparation eliminates the 

overstory and reduces the site to mineral soil. 

When soil preparation and planting are done 

during the fall and winter, the spring vegetation is sparse and all forest breeding birds 

are eliminated. Killdeers would be the only 

bird breeding in this habitat (Johnston and 

Odum 1956, Perkins 1973). However, if the 

site is not intensively prepared and "whips," 

shrubs, and logging slash are present, the 

breeding bird populations are considerably 

higher, possibly higher than populations in 

uncut loblolly-shortleaf forest (Perkins 1973). 

This would be true also for non-breeding bird 

populations. Snags left in harvested areas 

are important to cavity-nesting birds such as 

bluebirds (Sialia sialis) (Conner and Adkisson 

19741, woodpeckers, and other nesting birds; 

and they hardly affect timber production goals. 

Conner and Crawford (1974) found that one-yearold oak clearcuts with slash dnd debris were 

excellent foraging areas for Downy Woodpeckers 

and Hairy Woodpeckers (Picoides villosus); 

however, the source of insect prey was much 

less abundant in 5- and 12-year-old clearcuts. 

Perkins' (1973) data on bird species richness 

of mist blown-injected and bedded (with burned 

windrows) sites indicated that mist blowninjected sites have more than twice as many 

species during spring and summer as uncut 

forests. Many early successional bird species 

are common in these habitats, as the greater 

volume of vegetation in the lower strata significantly increases the number of species. 

Windrows often support plant comunities quite 

different from the adjacent treatment area 

(Perkins 1973). Shrubs and hardwood saplings 

in windrows create an "edge effect," which 

usually increases breeding bird species 

diversity and density. 

Clearcut size and shape, and juxtaposition 

of different age classes are important in bird 

management. Arner (1972) reported that the 

average size of clearcuts in southern forests r ,-, - 32 ha (range 20-600 ha) on cormereial land 

and 26 ha (Piedmont) to 36 ha (Coastal Plain) 

on public land. Clearcuts of 20 to 40 ha are 
acceptable units for nongame bird management. 

This range coincides with clearcut sizes suggested for many game species. Clearcuts 

larger tbqn 40 ha are less important to "edge" 

bird species, but, if rotations are long (60- 

80 years], these clearcuts could provide more 

habitat for forest interior species. 

Long narrow clearcuts clearly benefit 

"edge" species. However, a more important 

harvest treatment is the undulating boundary 

(scalloped edge), which is the natural edge of 

mature systems (Margalef 1968) . Meyers 

(unpublished data) has found significantly 

higher bird densities on scalloped forest edges 

of transmission line corridors. It is quite 

possible that clearcuts with undulating 

boundaries rather than straight boundaries are 

higher in bird density and diversity. Undulating boundaries have more edge and also 

create patchiness of habitat types. Further 

research on this phenomenon is needed before 

we make management recommendations. Johnston 

and Odum (1956) state that boundaries 

separating habitats of widely different age 

classes (e-g. grassland and forest) are most 

important to forest edge bird species. Clearcuts, by maximizing mature forest-grassland 

edge usually increase densities of edge bird 

species and bird species diversity. But, we 

caution against exclusive use of the "edge 

effect" as a management objective. Many of 

the edge species are common, whereas forest 

birds, particularly those of mature pine and 

hardwoods, are less common, and current forest 

management trends could further reduce their 

populations. 

Narrow spacing of trees on intensely 

managed sites usually causes early crown 

closure, while wider spacing of planted pines 

results in a delay in crown closure. The 

delayed crown closure benefits early sera1 

stage birds. Clumping from natural or aircraft seeding and seedling mortality from 

climatic or edaphic conditions both increase 

the variety of breeding birds. Regular spacing 

of trees possibly reduces bird species 

diversity (Roth 1976). 

High breeding bird densities (1800 pairs/ 

km2) in an intensively managed plantation 

interplanted with Norway spruce (Picea abies) 

and European beech (Fagus sylvatica) were 

reported by Williamson (1970). The plantation 

was bounded by a fringe of mature beech and 

oak, field hedgerows, and grassland access 

roads and firebreaks. The fringe of mature 

trees was used to screen the new plantation 

from the public roads. Although southern pine 

management currently does not include interplanting of hardwoods, birds would most Likely 

benefit greatly by this management. 

harvests--do not produce the very low bird 

diversity and density during the first year 

after harvest. The presence of overstory trees 

during the early stages of succession encourages 

both forest and field or shrubland breeding 

birds. Also, natural mortality of residual 

trees associated with these methods (Brender 

19731, provides bird habitat for nesting and 

foraging , 

Selection harvesting of loblolly and shortleaf pine is controversial. It is useful for 

managing small holdings where the landowners 

expect a regular income at short intervals. 

Sawtimber and veneer stock are the principal 

products of uneven-age management (Brender 

1973). Since selection harvesting is not a 

widely used method in the South, there have 

been no bird studies in uneven-aged loblollyshortleaf pine. Research on all silvicultural 

systems as they relate to bird habitat in 

southern pine forests is scarce. 

Intermediate Treatments 

At mid-rotation (about 15 years) pine 

stands, especially on dry sites, are devoid of 

groundstory vegetation. If there is a pulp 

market available, stands should be thinned, 

especially on average to poor sites (Brender 

1973). Thinning dense stands can significantly 

increase timber volume and provide improved 

bird habitat. Natural thinning encourages a 

patchier habitat than mechanical thinning and 

therefore may support more breeding bird 

species. However, if management of birds is 

of particular interest, mechanical methods that 

create non-uniform habitat are suitable, 

especially on poor to average sites that do not 

thin naturally. 

Burning is commonly prescribed in the 

management of loblolly-shortleaf pine forests 

for timber and game. Prescribed burning at 3- 

to 4-year intervals is useful in hardwood 

control and can create a patchiness in the 

understory that may increase bird species and 

densities. A few species, such as Bachman's 

Sparrow, benefit from more frequent prescribed 

burning. However, a vast majority of the 

breeding birds nest between ground level and 

3 m (Preston and Norris 1947); therefore without understory, significant numbers of breeding 

species are eliminated. Annual burning is not 

desirable for management of most songbirds, 

and for timber management generally is 

unnecessary. Noble and Hamilton (1976) concluded that burning at intervals of 3 to 4 

years provided the same results for forest 

management as annual burnina in a 46-year-old 

stand of loblolly pine. Research is needed on 

burning rotations greater than 4 years, spotburning, and other techniques of prescribed 

burning for non-game bird management. 

The other methods of regenerating evenaged stands--shelterwood and seed-tree 
PJATUZiAL WC3NTS MODIFYING BIPIIII mBITAT 

Two animals, the beaver (Castor 

canadensis) and the southern pine beetle, have 

a significant impact on forests by creating 

openings. Recse and Hair (l977) exmined 

birds associated with beaver pond habitat in 

South Carolina and found highly diverse communities, Bead standing trees, wetland habitat, 

forest edge, and abundant shrub cover are 

prominent components of beaver ponds. All of 

these structures contribute to the increased 

species diversity in the pond area. 

The southern pine beetle is one of the 

most damaging forest insects in the South (U. 

S. Forest Service 1969). Damage is within a 

well-defined area from the Piedmont in central 

Alabama to south-central Virginia with scattered areas reported on the Coastal Plain. 

The boundaries of the damage-prone area have 

changed little since the late 1800's (U. S. 

Forest Service 1969). Southern pine beetles 

are natural agents that set back succession. 

Dead standing trees in damaged areas are 

valuable woodpecker foraging areas and nest 

sites for cavity-nesting species. Small, 

scattered infested areas are important bird 

habitat; however, large areas are not as 

valuable to birds. 

Lightning strikes, damaging tropical 

stoms, glaze storms, and wild fires are significant agents modifying bird habitat in the 

loblofly-shortleaf pine type. Before the 

arrival of European man they were very 

important to bird species of earlier succes- sional stases. Liqhtninq-struck and winddamaged trees are readil:~ used by foraging 

woodpeckers and also are used as nest sites. 

Large wind-thrown areas create forest openings 

that are useful demonstration and management 

areas for the effects of natural habitat modifications on bird populations. Wildfires are 

of less importance today because of fire control technology. Large burned areas obviously 

benefit early sera1 stage birds, but the loss 

in lives, tipher, and property would be great 

if these fires were not controlled. Man 

replaces the effects of wildfires by harvesting 

and other silviculturaL practices. 

Regional Land use trends can significantly 

modify bird populations (Da&ach and Good 1940, 

Warbaeh 1958). In the Southern Piedmont a 

trend of increased ti&erland and decreased 

famland has been evident for the last 5 

decades. Small farms are being displaced by 

large agribusinesses employing highly mechanized and more intensive practices with 

fertilization, irrigation, and large open 

fields without hedgerows. High operation costs 

have eliminated diverse habitat that is 

valuable to many wildlife species on farmland. 

More land is used in crop production on today's 

highly mechanized Earns that depend heavily on 

outside energy sources (e.g. fertilizer, 

irrigation, pesticides). 

Private lands in relatively small holdings 

make up a significant percentage of the land 

area but receive relatively little attention 

from wildlife biologists. These lands usually 

are not available for management by wildlife 

biologists; but, we should make information 

available to landowners interested in bird 

management and recornend that they consider 

management of the entire bird cornunity and not 

individual species (except in the case of 

endangered species) . 

Rapid human population growth in the South 

is causing Large increases in subdivisions and 

corresponding loss of forest bird habitat. Few 

studies have been completed on the effects of 

subdivisions on summer and winter bird communities. None have been done in the loblollyshortleaf pine type. Commonly subdivisions 

are thought to provide only House Sparrow 

(Passer domesticus) and Starling (Sturnus 

vulgaris) habitat; however, with proper management and initial subdivision planning, these 

habitats should produce diverse bird comrnunities with very high densities. Subdivisions 

may be an important factor in the breeding 

range extensions of many songbird species. 

LITERATUa CITED 

American Ornithologists' Union. 

1957. Check-list of North American birds 

(5 ed.). A.O.U., Port City Press, Ine., 

Baltimore, Md. 691 p. 

American Ornithologists' Union. 

1973. Thirty-second supplement to the A.O.U. 

check-list of North American birds. Auk 

90:411-419. 

American Ornithologists' Union. 

1976. Thirty-third supplement to the A.O.U. 

check-list of North American birds. Auk 

93:875-879. 

Arnex, 13. ES. 

1972. Trends in management of the bobwhite 

quail on comercially owned Eorest Land and 

national forests of the southern region. 

- In J. A. Morrison and J. C. Lewis, eds. 

Proceedings of the first national bobwhite 

quail syn?posinx. Oklahoma State Univ., 

Stillwater, p. 11-15. 

Baker, W. W. 

1977, Roosting behavior of Red-cockaded 

Woodpeckers in north Florida. Smposium 

on Woot8ipecker Biolog-t~, 58th Annu. Meet. 

Wilson Ornithol, Soc., 19-22 May 1977. 

(Abstr .I 
Bock, C. E. and L. W. Lepthien. 

1974. Winter patterns of bird species 

diversity and abundance in the United 

States and southern Canada. Am. Birds 

28:556-562. 

Brender, E. tf. 

1973. Silviculture of loblolly pine in the 

Georgia Piedmont. Georgia For. Res. Gounc. 

Rep. No. 33, Macon, Ca . , 74 p , 

Brender, E. V. 

1974. Impact of past land use on the lower 

Piedmont forest. J. For, 72:34-36. 

Brunswig, N. L,, and A. S. Johnson. 

1972. Bobwhite quail foods and populations 

on pine plantations in the Georgia 

Piedmont during the first seven years 

following site preparation. Proc. 

Southeastern Assoc. Game and Fish Commissioners 26:96-107, 

Chamberlain, E. B. 

1974. Rare and endangered birds of the 

Southern National Forest. USDA, For. 

Serv. Southern Region, Atlanta, Ga., 

108 p. 

Conner, R. N., and C. S. Adkisson. 

1974. Eastern bluebirds nesting in 

clearcuts. J. Wildl. Manage. 38:934-935. 

Conner, R. N., and W. S, Crawford. 

1974. Woodpecker foraging in Appalachian 

clearcuts. J. For. 72:564-566. 

Dannbach, C. A., and E. E. Good. 

1940. The effect of certain land use 

practices on populations of breeding birds 

in southeastern Ohio. J. Wildl, Manage. 

4~63-76. 

Dickson, J. G., and 6- A. Segelguist. 

1978. Minter bird populations in pine and 

pine-hardwood forest stands in east Texas. 

Proc. Southeastern Assoc. Fish and Wildl. 

Agencies 31: (in press) . Harper, R. M. 

1943. Forests of Alabama, Geol. Surv. 

Alabama, Monogr. 10. 230 p. 

Hooper, R. G., M. R. Lennartz, and R. F, Harlow. 

1977. Territory and home range sizes of the 

Red-cockaded Woodpecker. Slmposiux on 

Woodpecker Biology, 58th Annu. Meet. 

Wilson Ornithol. Soc., 19-22 May 1977. 

t3i.bstr. ) 

Jackson, J. A. 

1977. Home range, interspecific competition, 

and management for Red-cockaded Woodpecker. 

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(Abstr. 1 

Johnson, A. S., 2. L. Landers, and T. D, 

Atkeson. 

1975. Wildlife in young pine plantations, 

- In H. L. Williston and W. E. BaLner, 

Progrm Chairmen. Proceedings symposium 

on management of young pines, 1974. USDA 

For. Serv., p, 147-1553. 

Johnston, C. W., and E. P. Odm. 

1956. Breeding bird populations in reiation 

to plant succession on the Piedmont of 

Georgia. Ecology 37:50-62, 

MacArtkur, a, H., and J. W, MaeArthcr, 

1961. On bird specles diversity. Ecology 

42: 594-598. 

Margalef , R, 

1868. Perspectives in eeoloc$.cal theory. 

Vniv. Chicago Press, Chicago, 1x1 p. 

Nelson, T. 6. 

1957. The original forests of the Georgia 

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Noble, R. E,, and R. B, NmiEtnn. 

1976, Bird populations in even-aged 

lcb1olly pine forests of southeastern 

Louisiana. Proc, Southeastern kssoc. Sane 

and Fish Comissioners 24:441-459, 

Odum, E. P., andG. L. Hight, 

1957. The use of mist nets in po~ulation 

studies of winter fringillids on the AEC 

Savannah River area. Bird-Banding 28:203- 

253. 

Oosting, H, J, 

1942. An ecological analysis of the plant 

communities of Piehont, North Carolina. 

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1973, Economic values and recreational 

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nongame blrds. 2 D. R. Smith, Tech. Coord. 

Proceedings of the symposiun on management 

of forest and range habitats for nongame 

birds, [May 6-9, 1975, Tucson, Ariz.] 

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Washington, D, C. p. 6-10. 

Perkins, C. J. 

1973. Effects of clearegtting and site 

preparation on the vegetation and wildlife 

in the flatwoods of Kemper County, 

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1947. Nesting heights cf breeding birds. 

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Quay, T. L. 

1947. Winter birds of upland plant 

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1977. Avian spesres diversity in relation 

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region of South Carol~na. Proc. Southeastern Asscc. Game and Fish Commissioners 

30: (in press). 

Roth, R, R. 

1976, SgxitLa1 heterogeneity ax3 bird species 

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fhugart, H. H., S, W. Anderson, and R, H. 

Strand, 

1935, Dominant patterns in bird populations 

of the eastern dcciduans forest biome. 

Publ. No, 697, Environ, Sci, DLV., Oak 

Ridge Mati. Lab, p, 90-95. 

Tramer, E- J, 

1968. An analysis of s~ecies diversity rn 

breeding bird ~opulations. Ph.D. dissert. 
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Tramer, E. 5. 

1974a. An analysis of the species density of 

U. S. landbirds during the winter using the 

1971 Christmas Bird Count. Am. Birds 

28:563-567. 

Triuner, E. 3. 

1974b. On latitudinal gradients in avian 

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1969. A forest atlas of the South. USDA 

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Wahlenberg, W. 6. 

1949. Forest succession in the southern 

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1958. Bird populations in relation to 

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Williamson, K. 

1970. Birds and modern forestry. Q. J. 

For. 64:346-355. 
Forest Bird Communities of the Bottomland Hardwoods 

3 / 

James G. ~ickson- 

------ 

Abstract.--Bottomland hardwoods, which are dwindling in 

area, support abundant breeding and winter birds. To help 

birds associated with bottomland hardwoods, land managers 

should: keep land in forests, maintain diversity of trees 

species and stand ages, maintain some old stands, maximize 

stand vertical foliage layers and habitat patchiness, and 

take special measures ----- for rare bird species. -p 

In 1970 the oak-gum-cypress forest complex, 

commonly called bottomland hardwoods, extended 

over about 1 3 m i l l i o n ha throughout the South 

(USDA 1975). This forest occurs mainly along 

major rivers and tributaries that extend into 

upland pine sites. Bottomland forests have 

long been recognized for their abundance of 

game animals, such as deer, turkey, and 

squirrels (Stransky and Nails 1968), and are 

also productive of nongame birds. 

type is a pioneer type found mainly on front 

land ridges and well-drained flats. The willow type is also a pioneer type usually found 

on front land sloughs and low flats. Riverfront hardwoods (sweet pecan, sycamore, hackberry, American elm, green ash) occur on all 

front lands except deep sloughs and swamps. 

The cypress-tupelo gum type grows in very low, 

poorly drained flats, deep sloughs, and swamps 

i n f i r s t bottoms and terraces, and in river 

estuaries. 

SITES AND FOREST TYPES 

FACTORS AFFECTING STAND COMPOSITION 

The two major areas in which bottomland 

hardwoods are found are first bottoms and terraces (Putnam 1951). First bottoms were 

formed by the present drainage system and are 

subject to frequent flooding unless afforded 

levee protection. Terraces were formed by 

earlier drainage systems and are not flooded 

except during superflood stages. Within both 

first bottoms and terraces are ridges, flats, 

sloughg, and swamps. New land or front is 

found only i n f i r s t bottoms. 

There are eight primary bottomland hardwood forest types and several variations of 

these (Putnam 1951). The sweetgum-water oak 

type is usually found on terrace flats and on 

first bottom flats and ridges. The white 

oaks-red oaks-hardwoods type occurs mainly on 

sandy loam soils of first bottom ridges and 

on terrace ridges. The hackberry-elm-ash 

type is found mainly on first bottom low 

ridges and flats, i n f i r s t bottom sloughs, on 

terrace flats, and in terrace sloughs. The 

overcup oak-bitter pecan type is situated on 

low, poorly drained flats, sloughs, and in 

the lowest backwater basins. The cottonwood 

I/ Research Wildlife Biologist, USDA 

 ores sf Service, Southern Forest Experiment 

Station, Wildlife Habitat and Silviculture 

Laboratory, Nacogdoches, Texas, in cooperation with School of Forestry, Stephen F. 

Austin State University, Eacogdoches. 

Natural Succession 

Tolerant species gradually replace intolerant species in the successional process. 

Eastern cottonwoodand black willow are the two 

main pioneer species on recent alluvium. They 

are intolerant of shade and will not succeed 

themselves. Cottonwood grows on higher sites 

having coarse-textured soils and is succeeded 

by riverfront hardwoods (Johnson 1973) , which 

are usually replaced by the sweetgum-water oak 

association (Putnam et al. 1460). Black willow establishes itself on fine-textured soils 

on lower sites and is normally succeeded by 

the hackberry-elm-ash association (Johnson 

1973). As the alluvium ages, these ridges and 

flats are occupied by a variety of species. 

A slow succession of plant communities 

occurs as sloughs and swamps fill with sediment (Putnam et al. 1960). Normally black 

willow first occupies the site, then is usually 

folIowed by bald cypress and tupelo in swamps 

and overcup oak and water hickory in small 

s rioughs . 

Geological Changes 

But differences in forest types mainly 

result from such geological changes as soil 

deposition, flooding, and changes in stream 

courses (Kosner and Minckler 1963, Broadfoot 
and Williston 1973), rather than from natural 

succession (Odum 1969). Floodwaters deposit 

coarse sands nearer channels and the fine 

clays away from channels. These deposits 

alter the sites and consequently the trees 

growing thereon. As silt builds up, streams 

and rivers change directions, thereby altering sites and stand composition. 

Animals and Fire 

The composition of bottomland hardwood 

stands has also been affected by insects, diseases, livestock and wildlife predation on 

seed and seedlings, and fire. For example, 

cattle can severely compact the soil and eliminate natural regeneration in overgrazed 

stands. Virtually all species of bottomland 

hardwoods are vulnerable to fires (Brown and 

Davis 1973), and past fires have consumed 

young vegetation in stands and provided entry 

for decay in older trees (Putnam 1951). 

Forest Management Practices 

Composition of most stands today reflects 

past decisions to cut the more valuable 

species and the more valuable individual trees 

(Putnam et al. 1960). For example, the tolerant boxelder persists in the understory of 

riverfront hardwoods and has dominated many 

sites after more valuable hardwoods were harvested (Johnson 1973). 

Management goals, stand composition, and 

species-site relationships determine the 

choice of regeneration system. The single 

tree selection system that has been used and 

often misued for so long in the South 

(McKnight and Johnson 1966) has fallen into 

disfavor. This regeneration system opens 

stands gradually and favors commercially less 

desirable, shade-tolerant species (Johnson 

1973). Most harvest/regeneration systems now 

being promoted favor the commercially valuable, 

intolerant species such as cottonwood, sycamore, and yellow poplar. 

Clearcutting is being conducted in evenaged cottonwood and willow stands, and is also 

appropriate where advanced reproduction is 

present, where sprouts will provide adequate 

regeneration, or where an appropriate seed 

source and receptive site occur together. 

Seed tree cuts, where 20 to 25 seed trees 

per ha are left, can be successful for light 

seeded species on exposed mineral soil. This 

technique has been used for cottonwoods 

(McKnight and Johnson 1966), but is sometimes 

impractical because good seed crops are difficult to obtain on mineral soil before the site 

is overcome by brush. 

In the shelterwood system, trees are harvested and the stand gradually opened in a 

series of cuts. Advance reproduction is established before the final cut. The shelterwood system is appropriate for heavy seeded 

species such as oaks, but is not satisfactory 

for species with intolerant seedlings 

(McKnight and Johnson 1966). 

Group selection is cutting in small patches (McKnight and Johnson 1966) and is appropriate where advance regeneration, sprouts, 

or a seed source will fill the vegetative void 

created by the harvest. 

Many mixed hardwood stands are being converted to hardwood monocultures. Cottonwood is 

the primary species planted, followed by sycamore and sweetgum. Cottonwood thrives on welldrained sandy and silty loams which are common 

in the batture (area between the river and levee) 

of the lower Mississippi River (XcKnight 1970). 

About 0.4 million ha are suitable for cottonwood plantations (Dutrow et al. 1970). 

Land Use Changes 

The conversion of hardwood stands to agricultural crops has had a severe impact on 

bottomland hardwoods, especially in the Mississippi Delta. In the early 1930% the Delta 

region of Arkansas, Mississippi, and Louisiana 

had nearly 4.8 million ha of hardwood forest 

(Sternitzke 1976). The last Forest Service 

surveys (1967 for Mississippi, 1969 for Arkansas, and 1974 for Louisiana) showed only 2.9 

million ha remained in hardwoods. Most cleared 

land went into soybean production. From 

1964 to 1974, eighty percent of cleared bottomland hardwoods in Louisiana went into soybeans, 

and most of the remainder was converted to improved pasture and cotton (Sternitzke 1976). 

Hardwood land along most rivers throughout the South has also been lost to reservoirs. In East Texas, for example, Toledo 

Bend and Sam Rayburn reservoirs alone occupy 

over 100 thousand ha which once supported 

mostly bottomland hardwoods. 

BIRD-HABITAT RELATIONSHIPS 

Birds are associated with numerous habitat 

parameters, such as number of vertical foliage 

layers (MacArthur and MacArthur 1961), total 

foliage volume (Willson 1974), foliage density 

near the ground (Dickson and Segelquist unpubL 

data), overstory hardwoodJconifer mixture 

(Hooper et al. 1973), habitat patchiness 

(Roth 19761, successional stage of stand 

(Shugart and James 1973), and moisture gradient (Bond 1957, Smith 1977). 

Bottomlands are normally moist for at 

least part of the year, although front ridges 

with sandy soils and flats with heavy clay 

soils often have little available moisture. 

The greater moisture on most bottomland sites 
usually allows more understory vegetation and 

should increase bird density. But long-term 

flooding and standing water in swamps can reduce or virtually eliminate foliage layers 

near the ground. This condition reduces 

ground nesting birds such as the Kentucky 

Varbler and overwintering ground foragers such 

as the mite-throated Sparrow {Dickson 19741, 

but may provide some protection from predators 

for colonial nesters such as herons, egrets, 

and Red-winged Blackbirds. 

Bird Populations in Breeding Season 

The moist bottomland hardwoods of the 

South support an abundance of breeding birds. 

When bird density and species diversity (calculated from the information theory, Shannon 

1948) in a pine, a pine-hardwood, and a mature bottomland hardwood stand were compared 

in an East Texas study (Anderson 1975), the 

hardwood sta2d had a higher bird density 

(1050 per kmi) during spring, than the other 

two stands (835 per km2--pine, 422 per km2-- 

pine/hardwood) . Number of bird species and 

species diversity were similar in the bottomland hardwood and pine-hardydood stands, but 

substantially higher than that in the pine 

stand. 

Similar results were evident from a comparison of breeding bird censuses in different 

habitats in the Louisiana-East Texas area 

{Table 1). Higher bird densities were recorded in mature bottomland hardwoods than in upland pine and pine-hardwood stands of different ages. Bird density in three bottomland 

hardwood stands ranged from 722 to 1480 

territorial male birds per kmL, about 2 to 4 

times that in the best upland stands. Bird 

species diversity in the bottomland hardwoods 

was higher than diversities in shorter pine 

and pine-hardwood stands, but about the same 

as that in mature upland pine and pine-hardwood stands of similar height. The bottomland 

hardwood stands would probably have had higher 

bird diversities but high stand densities (29- 

45 m2/ha basal area) limited light penetration, 

understory vegetation, and habitat patchiness. 

Some bird species are associated with 

stands of particular age and height classes. 

Bird species associatd with young stands (< 

4 rn tall) include the Yellow-breasted Chat, 

Common Yellowthroat, Indigo and Painted Buntings, and Red-headed Moodpeekers that nest in 

remnant snags. 

A sample of species and estimated densities of breeding birds in mature bottomland 

hardwoods in the Louisiana-East Texas area 

is shown in Table 2, Although some birds such 

as the Cardinal and Carolina Wren are ubiquitous in habitat distribution, other species 

are more restricted to deciduous bot tonland 

hardwood stands. Barred Owls and Redshouldered Hawks are two birds of prey conmonly found in hardwood bottoms, but they are not 

normally detected in singing male bird censuses of small areas. Wood ducks, which feed on 

hardwood,mast commonly nest in tree cavities. 

Many colonial nesters, such as the Yellowcrowned Night Heron, nest and feed in swamps 

throughout the South. The Yellow-billed 

Cuckoo is widespread in the canopy of hardwood 

bottoms. The Acadian Flycatcher is associated 

with moist forests (Shugart and .lanes 1973, 

Smith 1977) and is abundant in the LouisianaEast Texas hardwood bottoms. Prothonotary 

Warblers, Parula Warblers, and American Redstarts are all associated with floodplain forests in the Big Thicket area of East Texas 

(Bryan et al. 19751, and Prothonotary and 

Parula Warblers are comon during breeding 

season in swamps (Table 2) . The Prothonotary 

Warbler nests in cavities, which are abundant 

in trees killed by standing water. The Parula 

Warbler builds in nest in Spanishmoss, which 

is found in moist habitats (Lowery 1974: 505). 

The Swainson's Warbler, comon in the Louisiana hardwood bottom, is primarily associated 

with river floodplains and moist woods of the 

Southern Appalachians (Meanley 1971). 

Several rare (or extinct) species have 

been linked with southern bottomland hardwoods. 

Hooper and Hamel (1974) determined that nesting habitat of the extremely rare Bachman's 

Warbler had been bottomlands and headwater 

swamps that were inundated for short periods 

and subject to disturbances. The Ivory-billed 

Woodpecker, a bird of the once extensive ma-- 

ture bottomland hardwoods (Tanner 1942) , is 

now probably extinct because of timber cutting. 

Bird Populations in Winter 

Xature bottomland hardwoods have dense 

bird populations during the critical winter 

period. In a bottomland hardwood stand in 

East Texas, the estimated winter bird population was 1168 per km2, higher than numbers in 

a nearby pine stand (845 per km2) and in an 

adjacent pine-hardwood stand (672 per km2) 

(Anderson 1975). Number of species and species 

diversity varied little between stands. In a 

south central Louisiana mature hardwood bottom, estimated monthly winter populations 

varied between about 1400 and 2090 birds per 

km2, about twice the breeding bird density 

(Dickson unpubl. data). Winter visitors, 

which inhabit more northerly habitats or other 

habitats during breeding season, dominated 

the bird community. mite-throated Sparrow 

density approached 500 per b2 and Common 

Grackles varied between approximately 100 and 

1,000 per km2 (Dickson 1474). Red-headed 

IJoodpeckers, which select habitat with open 

understories during the breeding season, were 

common winter residents in the bottomland 

hardwoods. Yellow-bellied Sapsuckers, Blue 

Jays, Brown Thrashers, American Robins, Hermit 
Table 1.--Conparison of breeding bird density, diversity, and 

number of species in different habitats in Louisiana and East ~exas.u 

Bird species Number 

-- 

Bird density 

Stand o f iterritoriai 

diversit&' species males per kn") 

Small sapling 2.32 12 313 

f ap ling 1.06 3 25 

Pole 1.91 9 161 

Pole (Cleaveland 1973) 2.21 L L 205 

Sawtimber 2.66 18 365 

Sawtimber (Noble and 2.69 18 300 

Hamilton 1974) 

Small sap ling 

Sapling 

Pole 

Sawtimber 

Bottomland hardwoods 

Tupelo swamp (Ortego 2.69 23 1480 

and Noble 1975) 

Oak-gum (Dickson 1973) 2.32 15 752 

Oak-gum (Hightower et al. 2.40 2 2 864 

19 74) 

- I/Data from U.S. Forest Service studies and Breeding Bird Censuses 

published in American Birds. 

- L/~alculated from Shannon information formula (194Y), H' = -ipilnpi, 

where p = the proportion of all birds in a stand of each species, i 

Thrushes, and Ruby-crowned Kinglets are other unlike the natural uneven-aged stands of many 

birds comonly found in bottomland hardwoods tree species. Plantations can therefore be 

during winter - expected to have fewer birds and lower species 

diversity than natural stands. A recent inBreeding and Winter Bird Populations vestigation of wildlife populations in cottonin Hardwood Plantations wood plantations in Xississippi confirmed 

these expectations (Wesley et al. 1976). Birds 

In some har&.josd areas, primarily in the were censused in a natural stand and in an unMississippi Delta, uneven-aged stands are thinned plantation on Catfish Point and in a 

being converted to hardwood plantations, main- natural stand, an unthinned plantation, and a 

ly cottonwood, sweetgum, and sycamore. These thinned plantation on Huntington Point. Durplantations and natural cottonwood and willow ing winter there were 79 percent more birds in 

stands on new land are deficient in plant a natural stand than in an unthinned cottonspecies mixture and foliage height diversity, wood plantation. During breeding season, 
Table 2.--Territorial male birds per km2 in three mature bottomland 

hardwood stands in Louisiana and East ex as .l/ 

-- 

----- S t and 

Species Tupelo Oak-gum (La.) Oak-gum (Tx.) 

swamp (La.) 

Wood Duck 20 

Yellow-crowned Night Heron 20 

Purple Gallinule 10 

Yellow-billed Cuckoo 2 0 

Chimney Swift 4 0 

Pileated Woodpecker 

Ruby-throated Hummingbird 

Downy Woodpecker 80 

Great Crested Flycatcher 190 

Eastern Kingbird 10 

Acadian Flycatcher 140 

Eastern Wood Pewee 

Blue Jay 3 0 

Carolina Chickadee 30 

Tufted Titmouse 20 

White-breasted Nuthatch 

Carolina Wren 

Wood Thrush 

Blue-gray Gnatcatcher 

Starling 

White-eyed Vireo 

Yellow-throated Vireo 

Red-eyed Vireo 

Black-and-mite Warbler 

Parula Warbler 

Yellow-throated Warbler 

American Redstart 

Swainson's Warbler 
Table 2.--Continued 

- Stand 

Species Tupelo Oak-gum (La. ) Oak-gum (Tx, ) 

swamp (La*) 

Prothonotary Warbler 200 6 4 

Kentucky garbler 12 

Hooded Warbler 12 

Cornon Grackle 

Sumer Tanager 

Northern Oriole 

Cardinal 

Rufous-sided Towhee 

l/Data from breeding bird censuses published in American Birds: 

l?upe7o swamp (La.) (Ortego and Noble 1974), Oak-gum (La.) (Dickson 1973), 

Oak-gum (Tx.) (Hightower et al. 1974). 

bird density and number of bird species were 

consistently lower in unthinned cottonwood 

plantations than in natural stands. On 

Huntington Point in the thinned plantation, the 

number of breeding bird species was similar to 

that in the natural stand, but bird density 

was lower. Cavity nesters such as the larger 

woodpeckers, the Great Crested Flycatcher, 

and the Prothonotary Warbler avoided the 

thinned and unthinned plantations, as did 

some birds, such as Hooded and Kentucky Warblers, that are associated with hardwood midstory (Dickson and Noble in press). Although 

the number of bird species was lower in the 

plantations than in the natural stands, the 

investigators thought that number of bird 

species in the entire area was probably increased because some species such as Redwinged Blackbirds, Yellowthroats, Yellowbreasted Chats, Norther and Orchard Orioles, 

Rufous-sided Towhees, and Warbling Vireos 

were comonly found in plantations but not in 

natural stands. 

WYAGING BIRD WABITAT 

IN THE BOTTOMLAND HLLWWOOCS 

The main threat to birds that inhabit 

bottomland hardwoods is the conversion of forests to agricultural land and reservoirs. 

Thus, the first management priority should be 

to keep bottomlands in hardwoods. Birds such 

as Prothonotary and Parula Warblers, which 

have specific habitat requirements and are associated with bottomland hardwoods will decrease in proportion to their dwindling habitat. 

Land managers should maintain a diversity 

of tree species and age classes. Multiple 

objectives of bird and timber management can 

be met through harvesting by single tree selection, group selection, or small clearcuts 

(e.g. , < 40 ha). Interspersion of forest 

stands with non-forested land such as crops 

should increase bird diversity. 

Some natural mature stands (> 100 years 

old) should be maintained. Some birds af the 

bottomlands thrive in the canopy or sk:i!ed 

understory of mature stands. Decayed wood is 

abundant in natural mature stands but is being 

eliminated by intensive timber management. 

Many birds nest and feed in decayed wood. For 

nest building woodpeckers depend on trees infected withheart rots (Conner et al, 1976). 

Xany other secondary cavity nesters use woodpecker excavations for nests (Balda 1975). 

Although diversity of habitat should be 

used as a general guideline, some large mature stands (> 1000 ha) and corridors of mature trees between stands should be maintained. 

Such corridors should insure genetic variability by maintaining gene flow between bird 

populations that might otherwise become isolated. 
To increase bird density and diversity, 

managers should manipulate stands by plantings, thinnings, harvests, etc., that maximize 

foliage layers beneath the canopy. A basal 

area of about 20 m2 per ha over a portion of 

each stand should allow understory vegetation 

to develop, but be dense enough to curtail 

epicormic branching. Basal areas lower than 

20 m2 per ha can be maintained without profuse epicormic branching if thinnings and 

harvest cuts are conducted gradually. 

The same management techniques discussed 

above plus stand size can be used to enhance 

habitat patchiness by producing dense clumps 

of vegetation interspersed with sparse or 

open areas. 

Rare species, colonial nesters, and 

their respective habitats, deserve special 

efforts in research and habitat management. 

LITERATURE CITED 

Anderson, R. M. 

1975. Bird populations in three kinds of 

eastern Texas forests. M. S. Thesis. 

Stephen F. Austin State Univ., 

Nacogdoches, Texas. 98 pp. 

Balda, R. P. 

1975. The relationship of secondary cavity 

nesters to snag densities in western 

coniferous forests. U.S. Dep. Agric. 

For. Serv. Wildl. Habitat Tech. Bull. 1. 

37 pp. 

Bond, R. R. 

1957. Ecological distribution of breeding 

birds in the upland forests of southern 

Wisconsin. Ecol. Monogr. 27: 351-384. 

Broadfoot, W. M., and H. L. Williston. 

1973. Flooding effects on southern forests. 

J. For. 71:584-587. 

Brown, A. A. , and K. P. Davis. 

1973. Forest fire: control and use. 2nd 

ed., McGraw Hill Co., N. Y. 686 pp. 

Bryan, K. B., C. D. Fisher, D. E. Manry, and 

L.S. Risley. 

1975. Cormunity structure and distribution 

of the breeding avian fauna of the Big 

Thicket National Preserve. Tech. Rep. 

PX 7000-5-0771, USDI National Park 

Service, Santa Fe, New Mexico. 112 pp. 

Cleaveland, E. C. 

1973. Slash pine plantations. Pages 981- 

982 in W. T. Van Velzen (ed.), Thirtyseventh breeding bird census. Am. Birds 

27. 

Conner, R. N., 0. K. Miller, Jr., and C. S. 

Adkisson. 

1976. Woodpecker dependence on trees infected by fungal heart rots. Wilson 

Bull. 88:575-581. 

Dickson, J. G. 

1973. Mature'bottomland hardwood forest. 

Page 974 W. T. Van Velzen (ed.),Thirtyseventh breeding bird census. Am. Birds 27. 

Dickson, J. G. 

1974. Seasonal populations and vertical distribution of birds in a south central Lousiana bottomland hardwood forest. Ph.D. 

Thesis. La, State Univ., Baton Rouge. 

117 pp. 

Dickson, J. G., and R. E. Noble. 

Vertical distribution of birds in a 

Louisiana bottomland hardwood forest. 

Wilson Bull. (in press). 

Dutrow, G. F., J. S. McKnight, and S. 

Guttenberg. 

1970, Investment guide for cottonwood 

planters. U.S. Dep. Agric. For Serv. 

Res. Pap. SO-59. 15 pp. 

Hightower, S. B., C. D. Fisher, andM. L. Butts. 

1974. Southern flood plain forest. Page 

1011 & W. T. Van Velzen (ed.), Thirtyeighth breeding bird census. Am. Birds 28. 

Hooper, R. G., H. S. Crawford, and R. F.THarlow. 

1973. Bird density and diversity as related 

to vegetation in forest recreation areas. 

J. For. 71:766-769. 

Hooper, R. G., and P. B. Hamel. 

1977. Nesting habitat of Bachman's Warbler-- 

a review. Wilson Bull. 89:373-379. 

Hosner, J. F., and L. S. Minckler. 

1963. Bottomland hardwood forests of southern 

Illinois--regeneration and succession. 

Ecology 44:29-41. 

Johnson, R. L. 

1973. Oak-gum-cypress in the midsouth. 

Pages 98-102 2 Silvicultural systems for 

the major forest types of the United 

States. U.S. Dep. Agric. For. Serv. 

Agric. Handb. 445. 

Lowery, G. H. , Jr. 

1974. Louisiana birds. La. State Univ, 

Press. Baton Rouge. 651 pp. 

MacArthur, R. H., and J. W. MacArthur. 

1961. On bird species diversity. Ecology 

42:594-598. 

McKnight, J. S. 

1970. Planting cottonwood cuttings for timber production in the South. U.S. Dep. 

Agric. For. Serv. Res. Pap. SO-60. 17 pp. 
McKnight, 5. S., and R. L, Johnson, 

1966. The techniques of growing hardwoods. 

For. Famer 14th Manual Edition 25:59-65. 

Meanley, B, 

1971. Hature1 history of the Swainson's 

Warbler, U.S. Dep, Inter, Bur, Sport 

Fish, and WilbL,, K. km, Fauna No, 64, 

90 PP' 

Noble, R, E., and R. B, Hamilton. 

1974, LobIoLly pine forest. Pages 1020- 

2021 5 W, T, Van lkelz~n (ed. ) , Thirtyeighth breeding bird census, &* Bird5 28* 

Odram, E, P, 

1969. The strategy of ecosystem development. Science 164:262--270, 

Orrego, B., and Re N, NdbLe. 

1975. Tupelo swamp, Pages 1097-1098 

W. T. Van Velzen (ed.), Thirty-ninth 

breeding bird census. Am, Birds 29. 

Putnam, J, A. 

1951. Management of bottomland hardwoods. 

U.S, Dep, Agric. For. Serv, , South. For. 

Exp, Stn. Occas, Pap, 116. 60 pp. 

Futnam, J. A,, G, M, Furnival, and J. S. 

McKnig"n. 

1960. Management and inventory of southern 

hardwoods. U,S. Dep, Agric, For, Serv. 

Agric. Bandb. 181. 102 pp. 

Roth, R. R. 

1976. Spatial heterogeneity and bird 

species diversity. Ecology 57: 773-782. 

Shannon, C, E. 

1948. A mathematical theory of comunication, Bell Syst, Tech, J. 27:339-432, 

623-656. 

Shugart, B, H., Jr., and D. James. 

1973. Ecological succession of breeding 

bird populations in northwestern krkansas. Auk 90:62-77, 

Smith, M. 6. 

1977. Distribution of summer birds along 

a forest moisture gradient in an Ozark 

watershed. Ecology 55:810-919, 

Sternitzke, Ha S, 

1976. Impact of changing land use on delta 

hardwood forests, J. For. 44:25-27, 

Tanner, 3. T. 

1942. The Ivory-billed Woodpecker. 

Naticnal Audubon Society Res, Rep. No. 

I. E.U., 111 pp. 

U. S. Department sf Agriculture, Forest 

Service 

1977. The nation's renewable resources-- 

an assessment, 1975. For. Res. Rep. 21. 

243 pp. 

Wesley, D. E,, 6. J* Perkins, and A. D. 

Sullivan. 

1976. Preliminary observations of cottonwood platations as wildlife habitat. 

Pages 460-476 Proc. Synp. East. Cottsnwood and Related Species, Greenville, 

Miss. 

WilPson, M. E. 

1974. Avian community organization and 

habitat structure. Ecology 55:1017-1029. 

Stransky, 3. J., and L, K* Halls, 

1965. Woodland management trends that 

affect game in coastal plain forest types. 

Prsc. Annz. Conf, Southeast. Asscc. Game 

Fish Corn, 21: 104-109, 

EFECTS OF tJLATJAGEilE:3T PRACTICES 

ON XOXGA:;fE BIRDS (continued) 

lioderator : J. TJ. Hardy 

Florida State Museum 
Oak-Pine and Oak-Hickory Forest Bird Communities and Management 

Options 

1 / Keith E. EvansAbstract,--Succession%l trends, soil-site 

characteristics, and land use options in the oak-pine and 

oak-hickory forest types are discussed in relation to 

bird populations ad bird-habitat associations. Management guidelines are provided. Management alternatives 

inc lude attracting birds to recreational areas, identifying unique birding areas, managing for ecosystem integrity, 

and enhancing the habitat for cavity nesting bird species. 

INTRODUCTION 

The 125 million acre oak-hickory and 

the 34.5 million acre oak-pine forest types 

make up most of the inland forests of 

eastern United States and account for 30 

percent of all commercial timberland in the 

United States (USDA Forest Service 1977). 

In addition, much of the loblolly-shortleaf 

pine forests would be replaced by oak-hickory 

species if successional trends were unchecked 

(USDA Forest Service 1973a). 

These vast forests are extremely 

important to many birds. From 300 to 400 

species use the area each year, and 150 to 

200 of them nest in the eastern midcontinent 

region. I recognize that many of these 

species are not dependent directly on the 

oak-hickory and oak-pine forest types. 

Emphasis will be on those bird species that 

nest or winter in association with oakhickory and oak-pine types. Migrating 

species, although important, seem more 

adaptable to habitat variations and are less 

affected by most forest management options. 

Management goals for migrants should be 

directed to those species with specific 

needs (Sprunt 1975). 

I/Principal Wildlife Biologist , North 

Central Forest Experiment Station, Forest 

Service, E.S, Department of Agriculture, 

Columbia, Ffissouri. 

Many agencies, including the Forest 

Service, have recently expended much effort 

to include nongame birds in their management 

plans. The main cooperative endeavors include: (I) Service-wide Timber-Wildlife 

Coordination Workshop (USDA Forest Service 

1973b), (2) Timber-Wildlife Management Symposium (Slusher and Hinckley 1974), and (3) 

Symposium on the Management of Forest and 

Range Habitats for Nongame Birds (Smith 1975). 

These efforts along with regional workshops 

will set-the-stage for future management programs and identify high priority research 

needs. 

PLANT COmUNITIES 

The area occupied by oak-hickory and 

oak-pine forest is highly diverse due to 

elevation gradients, north-south climatic 

gradients, topography, soil-site differences, 

aspect, successional stages, and land-use 

options, Somewhere between 3,000 and 5,000 

plant species occur in the area. Most of the 

emphasis in this paper will be on vegetative 

shape or structure and the variations in 

structural attributes caused by succession, 

soil-site characteristics, and land useoptions. 

Natural Succession 

Oak-Hickory Forests 

Succession is a dynamic process with 

rapid changes occurring for approximately 40 

years before a more or less stable oak-hickory 

forest community persists. The first year 

after a cultivated field is abandoned, a wide 

variety of annual grasses and forbs appear. 
Years 3 to 6 show a change from annual species 

to perennial grasses and forbs, and shrubs 

begin to invade. Years 6 to 15 are the 

"brush" years--shrub species dominate and 

there is an increase in post oak, shagbark 

hickory, and the clonal tree species. By 

year 15 many clonal species such as persimmon 

are decreasing. Between years 15 and 40, an 

increase occurs in the more climax species 

such as white and black oak (Drew 1942, 

Shelford 1963). The quality of the site 

determines the dominants in the older oakhickory stands. The best sites will produce 

white, red, and black oak; the intemediate 

sites will produce white and post oak; and 

the poor sites will produce mostly post and 

black jack oak. 

Oak-Pine Forests 

Succession for the oak-pine type is 

similar to the oak-hickory except that pine 

seedlings come in after site disturbances. 

The pine often persist for up to 100 years. 

In the piedmont area, abandoned cultivated 

areas will first be vegetated with annual 

forbs and horseweed and then be invaded 

with broomsedge. The broomsedge (as a 

dominant) will be replaced by pine after 

about 6 years. The oak-pine forests that 

develop often contain large amounts of yellowpoplar and blackgum after 15 to 40 years of 

succession. If logging, fire, and other 

disturbances are eliminated, the oak-hickory 

forest components will begin to dominate 

after 40 years (Oosting 1942, Johnston and 

Odum 1956). 

Old field successional stages are 

different than succession after a clearcut. 

These differences are more obvious in the 

oak-pine type than in the oak-hickory type. 

Old fields proceed into nearly pure pine 

stands that persist for many years before 

the oak forest components appear. However, 

when an oak-pine forest is clearcut, the 

entire range of oak-pine forest components 

will be present throughout stand development. 

For the purposes of this paper, my comments 

will include forest situations where oakpine components exist and exclude situations 

where the land-use option is to maintain 

and manage for pine. 

Soil-Si te Characteris tics 

characteristics must be considered as an 

integral part of a model that associates bird 

species with attributes of nesting, roosting, 

and feeding sites. 

A relatively tight crown closure is 

common throughout the oak-hickory and oak-pine 

forests. Murphy and Crawford (1970) found 

that 85 percent of their oak-pine plots, and 

91 percent of their oak and mixed hardwood 

plots had a crown closure exceeding 70 percent. 

Total vegetation production on these plots was 

generally less than 200 pounds of oven dry 

material per acre per year. Density of forest stands and crown closure probably influence 

understory development more than any other 

factors (Table 1) . 

Table 1.--Frequency of occurrence of forest 

understory plants in Missouri (Murphy and 

Crawford 1970). (In percent) 

: Oak- : Black- :White 

Plant : pine : scarlet : oak 

: oak : 

Panic grass 2 6 19 2 6 

Little blues kem 

and broomsedge 23 13 12 

Sedge 14 18 2 2 

Poverty oatgrass 9 8 11 

Lespedeza 3 3 2 2 2 4 

Tick tref oi 1 2 7 2 7 40 

Aster 2 5 2 2 2 4 

Pussytoes 17 12 21 

Dittany 13 8 15 

 oat's rue 13 - - - - 

Sunflower 9 9 - - 

B lueberry 42 2 8 3 2 

Hickory 20 23 16 

White oak 19 18 34 

Sassafras 18 2 1 15 

Black oak 15 18 15 

Pos t oak 12 I1 - - Shortleaf pine 11 - - - - Scarlet oak 10 8 - - Grape 10 12 13 

Flowering dogwood 9 10 17 

Woodb ine - - 9 14 

Hawkweed .. - - - 8 

B lackgum - - . - 10 

Soil-site attributes play an important 

role in the structural development of a 

forest. The better sites tend to have more 

plant species and a more developed understory. Soil type and fertility is an 

ecological force that influences the quantity and quality of food and cover. Thus soil 
Stand development after a regeneration 

cut in upland hardxgoods is similar to old 

field natural successbn except for a short 

herbaceous stage. The first 10 to 15 years 

after a regeneration cut are referred to as 

the "brushft stage when 25,000 woody stems per 

hectare is common. By year 20, 75 percent of 

these will die on areas with a site index of 

55, 80 percent will die on areas with a site 

index of 65, and 85 percent will die on areas 

with a site index of 75. By age 80, natural 

death in unthinned stands will eliminate 90 

percent of the woody stems that were present 

at age 20. By age 80, site index 55 areas 

will support approximately 600 trees per 

hectare (average of 23.4 cm d.b.h.), site 

index 65 will have 460 trees per hectare 

(average of 27.2 cm d.b.h.), and site index 

75 will have 410 trees per hectare (average 

of 29.2 cm d.b.h.) (Gingrich 1971). These 

dead and dying trees provide important nesting sites and feeding resources for many 

birds throughout the rotation age of the 

forest (Hardin and Evans 1977) . 

Land Use Impacts 

Timber, range, agriculture, and urban 

activities, along with many other land use 

options, have a significant impact on the 

structural characteristics and successional 

stages of forest areas (Table 2), Species 

composition changes as vegetation type and 

structure changes, but all birds are never 

eliminated. From the diverse hsbitat preferences of eastern deciduous bird species, 

and the large number of species selecting 

edge types, we can assume that these species 

evolved in an area of high diversity with 

considerable edge. The greatest potential 

de trirnental impacts of modern silvicultural 

practices are probably the removal of cull 

and dead trees and the elimination of large 

tracts of old growth. 

Table 2.--A digitized classification system 

for the vegetational conditions (structural 

communities) existing in the area of 

eastern United States occupied by oakhickory and oak-pine forest types 

100 Forest openings 

110 Cultivated, row crops 

120 Pasture 

121 Mowed 

122 Grazed 

130 Early successional stages or shallow 

soil 

I31 Bare ground and rock outcrops 

132 Low herbaceous cover, mostly 

annual plants 

133 Herbaceous, mostly perennial 

grasses and forbs 

134 Herbaceous, mostly grasses and 

Eorbs with shrub invasion 

135 Clonal shrubs such as corralberry, persimmon, and eastern 

redcedar 

136 Small tree glade, with eastern 

redcedar, winged elm , sumac, 

persimmon, and mixed hardwoods 

less than 4 m tall 

200 Urban areas 

300 Forest and woodland 

310 Regeneration (less than 5 cm d.b,h.) 

311 Without site preparation 

312 With site preparation 

320 Seedling-sapling (5-10 cm d.b. h.) 

321 Natural regeneration 

322 Artificial regeneration 

330 Pole stand (10-25 cm d.b.h.) 

331 Natural thinning only 

331.1 Limited understory 

331.2 Primarily grass-forb 

understory 

331.3 Primarily low shrub 

understory 

331.4 Primarily shade tolerant 

midstory species in 

understory 

331.5 Well developed multilayered understory 

332 Thinning, selection harvest 

332.1 Limited understory 

332.2 Primarily grass-forb 

understory 

332.3 Primarily low shrub 

understory 

332.4 Primarily shade tolerant 

midstory species in 

understory 

332.5 Well developed multilayered understory 

340 Sawlog stand (more than 25 cm d.b.h.) 

341 Natural thinning only 

341.1 Limited understory 

341.2 Primarily grass-forb 

understory 

341.3 Primarily low shrub 

understory 

341.4 Primarily shade tolerant 

midstory species in 

understory 

341.5 Well developed multilayered understory 

342 Thinning, selection harvest 

342.1 Limited understory 

342.2 Primarily grass-forb 

understory 

342.3 Primarily low shrub 

understory 

342.4 Primarily shade tolerant 

midstory species in 

understory 

342.5 Well developed multilayered understory 
350 Old growth (a stand older than 

"economic rotation age, 'hsually 

characterized by an overstory of 

old trees of which many are suitable for cavity nesting species) 

351 Natural thinning only 

351.1 Limited understory 

351.2 Primarily grass- forb 

understory 

351.3 Primarily low shrub 

understory 

351.4 Primarily shade tolerant nidstory species 

in understory 

351,s \$ell developed multilayered understory 

352 Thinning, selection harvest 

352.1 Limited understory 

352.2 Primarily grass- forb 

understory 

352.3 Primarily low shrub 

understory 

352.4 Primarily shade tolerant midstory species in 

understory 

352.5 Well developed multilayered understory 

400 Water influence zones 

410 Vegetation associated with perennial 

streams 

420 Vegetation associated with intermittent streams 

430 Vegetation associated with large 

reservoirs 

440 Vegetation associated with ponds, 

sinkholes, and springs 

Originally, the majority of the eastern 

United States was a mature (old growth) 

deciduous forest. The exact pattern of the 

mosaic of successional stages is unknown. 

John J. Audubon and Alexander Wilson in their 

extensive travels throughout the region saw 

only a limited number of birds that are restricted to brushy successional stages 

(Griscom and Sprunt 1957). Their journals 

indicate that extensive tracts of old growth 

forests were common. Little information is 

available on bird population levels jn climax 

forest stands. Most stands that have been 

studied are small Erapents (forest islands) 

and bird population composition and density 

is strongly influenced by the 'kedge effect" 

(Table 3). *Most forest interior bird species 

are able to breed in forest fragments as 

small as 35 acres (15 ha). However, 

MacGLintock et al. (1977) stated that this is 

apparently only possible if the fragment is 

"subsidized" by a nearby major forest system. 

Table 3.--Population of the comon breeding 

bird species on two mature (possibly 

climax) forests: (a) oak-hickory forest 

in West Virginia and (b) oak-hickory hardwoods of the Southern Piedmont Plateau in 

North Carolina (Loery 1966) 

Bird species : Forest habitat 

(Birds/40 ha or 

100 acres) 

Red-eyed vireo 

Ovenbird 

Wood thrush 

Cardinal 

Carolina chickadee 

B Lack- throated green 

warbler 

Tufted titmouse 

Black and white warbler 

Cerulean warbler 

Blue jay 

Ye l low- throa ted vireo 

Solitary vireo 

Hooded warbler 

Acadian flycatcher 

Brown-headed cowbird 

Scarlet tanger 

Blackburnian warbler 

Eastern wood pewee 

Downy woodpecker 

Great crested flycatcher 

Red-bellied woodpecker 

Carolina wren 

White-eyed vireo 

Rufous-sided towhee 

Common flicker 

Hairy woodpecker 

Summer tanager 

White-breasted nuthatch 

Blue-gray gna tcatcher 

Worm-eating warbler 

Black- throated blue warbler 
The study of habitat selection by birds 

is a fascinating but complex subject. Each 

bird seems to have a physiological and 

behavioral preference for a certain set of 

habitat attributes. Although there are 

variations in the habitats chosen by different individuals of the same species, there 

are generally larger differences between 

habitats chosen by different species, This 

fact enables us to describe vegetation conditions (types) that are preferred by 

certain species. For example, we know that 

killdeer prefer a bare ground type, that 

yellow-breasted chats prefer a brushy area, 

and that pileated woodpeckers prefer extensive areas of mature or over-mature 

forests. But why should species have a 

preferred habitat? Because the presence of 

other species makes it necessary to specialize. This specialization more efficiently 

utilizes all the components of the environment and lessens competition between species. 

Any change in vegetation type or structure 

throughout the oak-hickory or oak-pine forests will change the bird species composition 

(Tables 4 and 5). 
Table 4.--Abundance of bird species found in various stages of oak-pine succession (adapted 

from Johnston and Odum 1956) 

Dominant plants and age in years of study area 

: OakBird species : Grass- : : hickory 

: Forbs : Grass : shrub : Pine forest : climax 

: 1-2 : 2-3 : 15 : 20 : 25 : 35 : 60 : LOO : 150-200 

Grassb ~pper sparrow 

1 i B- A a 

Eastern meadowlark C B Eii C 

Field sparrow AA A C C 

Ye llowthroat B B 

Ye Llow-breas ted chat C B 

Cardinal C C B B B 

Rufous- s ided towhee C C B B B 

Bachman's sparrow C C C 

Prairie warbler C C 

White-eyed vireo C C C 

Pine warbler B A B 

Summer tanager C B B B 

Carolina wren C C B 

Carolina chickadee C C C 

Blue-gray gnatcatcher C B B 

Brown-headed nuthatch C 

Eastern wood pewee B C 

Bumingb ird B B 

Tufted titmouse C B 

Yellow- throated vireo C C 

Hooded warbler C 13 

Red-eyed vireo C A 

Hairy woodpecker C C 

Downy woodpecker C C 

Great crested flycatcher C C 

Wood thrush C A 

Yellow-billed cuckoo B 

Black and white warbler C 

Kentucky warbler C 

Acadian flycatcher C 

Totals : (including rare 

ot listed 

L/A is most abundant, 8 is abundant, and C is common. 
Table 5.--Abundance of bird species found in various age stands after clearcutting a mixed oak 

stand in Virginia (adapted from Conner and Adkisson 1975) 

: 1-year-old : 3-year-old : 7-year-old : 12-year-old : Pole : Mature Species : clearcut : clearcut : clearcut : clearcut : stand : stand 

Eastern bluebird 1 / A- C C C 

Indigo bunting A B B C 

Carolina wren B C C C 

Comon flicker B C C C 

Carolina chickadee C C 

Downy woodpecker C 

American goldfinch C C C C 

Brown- headed cowbird B C C C 

Prairie warbler B B A 

Field sparrow B B C 

Ruf ous-sided towhee B B B 

Yellow-breas ted chat C C B 

Hooded warbler C C B 

Golden-winged warbler C C C 

Cardinal C C C 

B lue-winged warbler C C 

Brown thrasher C 

Chestnut-sided warbler C C 

Ruby- throated humingbird C C 

Hairy woodpecker C 

Catbird C 

Worm-eating warbler C 

Kentucky warbler 

Whip-poor-will 

White-eyed vireo 

Eastern wood pewee C 

Red-eyed vireo B 

Great crested flycatcher C 

Black and white warbler 

Scarlet tanager C 

Ovenbird B 

Lue-gray gnatcatcher C 

"'ood thrush B 

xcadian flycatcher C 

Tufted titmouse C 

i leated woodpecker C 

White-breasted nuthatch C 

'i-irkey C 

Ffed grouse C 

,;&er of bird species 

- ohserved 39 162 154 143 44 9 3 

l i - A is most abundant, B is abundant, and C is common. 
The word habitat is often used in 

reference to a specific mapable unit or 

obvious vegetation condition. Several species 

co-exist in any selected vegetation type 

(mapable habitat unit)--for example, an oakhickory well stocked pole stand with limited 

understory (Table 2, number 331.1) might be 

inhabited by red-eyed vireos, tufted titmice, 

downy woodpeckers , b lue-gray gna tca tchers , and many others. The Volterra-Gause principle asserts the two species cannot co-exist 

indefinitely if they are limited in their 

population size by the same factors. This 

principle implies that co-exis ting species 

are limited by different factors. These 

differences are of ten complex and subtle. 

Shugart et a1 (1975) touched on this principle when they listed groups of birds that 

co-existed in a given vegetation type, but 

used the resources differently. For example, 

kinglets, titmice, and chickadees have 

similar feeding behavior, but different food 

preferences; red-eyed vireos, Carolina wrens, 

and ruby-crowned kinglets eat similar foods, 

but have different feeding behavior. From a 

management point-of-view, I feel that it is 

important to indicate groups of species that 

will co-exist in one vegetation type without 

long discussions of the subtle differences 

(Tables 4 and 5). 

One other idea pursued in the management 

guidelines is the recognition that bird 

species vary greatly in the specificity of 

their habitat requirements. The stenoecious 

species, those with limited adaptability to 

habitat variability, provide the greatest 

potential and challenge for management. 

These species require a specific habitat 

component (or components) to complete at 

least one phase of their life cycle. Most 

of the rare, endangered and threatened 

species are stenoecious. 

Structure of vegetation tends to play 

a dominant role in bird habitat selection 

processes (Lack 1933, Miller 1942, Kendeigh 

1945, Bond 1957 and others). For example, 

several warbler species will live in a 

mature lowland forest with an understory of 

giant cane but, as shown below they utilize 

different resource attributes. 

Height of 

nest or 

foraging Feeding 

Species area sites 

Cerulean warbler Tree tops (canopy) 

Yellow- throated 15 m Glean from small 

warbler limbs 

Black and white Glean from large 

warbler 1 imb s 

Parula warbler 10 m Generalist 

Reds tart Second groxqth, 

large insect 

Prey 

Ye 1 low warbler 7 m Water edge 

Pro thono tary Cavity nester 

warbler 

Kentucky 5 m Feeds by gleanwarbler ing 

Hooded warbler Feeds by hawking 

Wonnea t ing Steep slope 

warbler 

swainson's In giant cane 

warbler 

La. waterthrush 0 m Along streams 

To maintain a full and natural complement 

of wildlife species, a full and natural complement of plant communities (habitats) must 

be retained in the landscape. Forest areas 

are in a continual state of flux and the 

distribution of comparable areas of vegetation 

varies with time (succession) and space 

(aerial extent). Land use, soil, and landform 

are each horizontal components of habitat 

heterogeneity whereas the abundance of forb, 

shrub, midstory, and canopy species are 

vertical components of habitat heterogeneity. 

The horizontal and vertical components are 

interrelated, both between the components and 

within the attributes of each component. A 

similar arrangement of components results in 

a stand. There will be variability within a 

stand, but generally management resolution 

will not be concerned with subtle variations. 

A sufficient number and arrangement of stands 

of each vegetation condition (sera1 stage) is 

necessary to harbor oganisms requiring specific habitats, because succession, land use 

options, and local disasters will continually 

cause areas to be unsuitable to some species. 
A full vegetative complement including 

mature and dead standing trees, full understery and shrub Layer and wide edges is 

necessary to maintain diverse breeding bird 

populations (Linehan et a1 1967 and Verner 

1975). Siderits (1975) indicated that plant 

species compositions, age-class and spatial 

coverage of stands are the most easily manipulated, ?faximum diversity is a lower 

priority objective than maintaining a good 

distribution of the adapted com~unities, 

Communities skouLd be delineated on the basis 

of plant species dominants, age, and stockirtg level. This type of management will 

benefit most species. The remaining species 

of interest--those with specific habitat 

components, endacgered , threatened, or unique 

status, or those of economic importance-- 

will require specifically designed programs. 

Specialized nanagenent plans could be 

initiated \here one or mare species requires 

"featuring" because of low population numbers, res eric ted range, or special interest, 

For example, a -rescription might call for 

the control of ~cderstory shrub species in 

a mature forest to create a park-like stand 

for the ~ooper's hawk, barred owl, prothonotary warbler, robin, and red-headed woodpecker, Another prescription would be to 

maintain an old fieid in Low growing herbaceous cover to provide habitat for eastern 

meadowla--ks, several species of sparrows, 

and bobt, ; tes. Other birds that show defini te hab; :*it preferences include : those 

that depend on Large trees (northern oriole 

and hooded warbler) ; those that depend on 

brushland (common yellowthroat, gray catbird, 

yellw-breasted chat, white-eyed vireo, and 

Kentucky warbler) ; and the forest edge 

species (mockingbird, yellow warbler, indigo 

bunting, and blue-winged warbler). 

The oak-pine forests are of greater 

value to wintering bird populations than 

are the oak-hickory forests (Table 6). At 

least two major factors enter into this 

importance--the oak-pine forests are more 

southern and the coniferous tree component 

provides additional cover, The true importance of the oak-pine and oak-hickory 

forests in protecting and feeding wintering 

populations and, thus, maintaining breeding 

populakion is unknown. 

Table 6.--Population levels of common wintering birds on three habitat types: (A) oakhickory forest in Kansas, (B) mixed pinedeciduous forest in Louisiana, and (C) 

upland oak-hickory forest in Virginia 

(Ryder and Ryder 1976) 

Species : Habitat type :A B C 

(BirdsJ40 ha or 100 acres) 

Common grackle 

White-throated 

sparrow 

Rub y-crowned 

kinglet 

Red-headed 

woodpecker 

Tufted titmouse 

Blue jay 

B lack-capped 

chickadee 

Carolina 

chickadee 

Pine warbler 

Red-bellied 

woodpecker 

Carolina wren 

Common crow 

Dark-eyed junco 

American robin 

Ye1 low-rumped 

warbler 

Cardinal 

Whi t e - b r e a s t e d 

nuthatch 

Go lden-crowned 

kinglet 

American goldfinch 

Downy woodpecker 

Brown creeper 

Common flicker 

Ye llow-bellied 

sapsucker 

Red-breas ted 

nuthatch 

Bobwhite 

Eastern phoebe 

Hermit thrush 

Hairy woodpecker 

Pi leated woodpecker - 4 
The wildlife management profession has 

evolved through four distinct phases since 

its birth in the United States in the early 

1900's. These phases are: (1) awakening of 

the public, (2) protection of a dwindling 

resource, (3) single species management, and 

(4) the presently favored "holistic " approach 

that involves intensive coordination with 

other program objectlves. This last phase 

promises to be the most complex, but is 

potentially the most rewarding. 

Setting specific management goals for a 

resource as large and diverse as eastern 

United States avifauna is complex, confusing, 

often contradictory, and maybe somewhat naive. 

Many approaches have been suggested and/or 

tried such as to: (1) maximize vertical 

and/or horizontal vegetational diversity, , 

(2) maximize density of a featured species, 

(3) maximize number of species in a "key" 

area--from a recreational point-of-view 

this maximizes the probability of interspecific encounter, and (4) manage for 

economic commodities and let the birds 

adapt . 

In designing management programs, two 

assumptions should be applied. First, each 

species should be recognized for its intrinsic value in ensuring the perpetuation of 

natural ecosystems. Therefore, all native 

species should be protected and efforts 

directed toward achieving and/or maintaining 

self-sustaining population levels. Second, 

different values can exist compatibly on 

the same area or in close proximity. Therefore, the needless sacrifice of any value is 

indefensible and the failure to make the most 

of all values is a dereliction of sound 

management. This still allows for areas 

where trees ought not be cut, others where 

game ought not be harvested, and others 

where the public should be excluded. 

I won't discuss the many forest 

management options that exist because these 

have been discussed in Zeedyk and Evans 

(1975) and Sander (1977). Three major 

options exist--even-aged management, unevenaged management, and preservation. 

With few exceptions (Marquis 1967) 

even-aged management is rec 

wood sil~i~~lt~rists, primarily because 

other systems fail to produce adequate reproduction and growth of desirable intolerant 

species (Sander and Clark 1971, Trimble 1970, 

Arend and Scholz 1969, Roach and Gingrich 

1968). Three silvicultural cutting systems 

are employed to achieve even-aged stands-- 

seedtree, shelterwood, and clearcutting. 

Stands typically pass through six recognizable 

s tages--annual weed, brush, sap ling, pole, 

small sawtimber, and mature sawtimber. The 

two types of operations in the life of an 

even-aged stand are the harvest cutting and 

intermediate treatments (thinnings), The 

impacts of these operations on bird populations 

are discussed in detail by Webb et 9 (1977). 

For the purposes of this paper unevenaged and all-aged management are lumped. 

Harvesting is done at scheduled intervals and 

the trees to be cut are selected, whether 

individually or in small groups. Selection 

is made on the basis of age, diameter, vigor, 

form, and species. Noncommercial treatment 

may follow commercial harvest to remove cull 

stems and undesirable species. Regulation is 

by volume and diameter rather than by area, 

Uneven-aged management tends to favor shadetolerant species and to maintain a climax 

state or advance plant succession toward the 

climax community (Filip 1973). Intolerant 

or midtolerant species may sprout but fail 

to develop, thus the selection system is not 

recommended for oak silviculture. Some 

woodland owners practice uneven-aged management or "selection forestry" largely for 

aesthetic reasons. 

Uneven-aged management tends to decrease 

tree species diversity and overstory biomass 

variations. Thus vertical diversity is enhanced and horizontal diversity reduced. I 

found no direct information on how these 

changes influence bird populations but I can 

speculate on a few changes. The amount of 

edge habitats would probably decrease within 

a management unit. Some birds, like the catbird, seem to adjust to small openings (Bond 

1957) and may utilize the edges resulting 

from group selection cutting. Birds that 

require larger openings would not adjust to 

uneven-aged management options. The noncommercial removal of snags and cull trees 

may influence cavity nesting species. Here 

again information is lacking on specific comparisons of vertical and horizontal plant 

diversity. 

Preservation as a management option has as 

its objective the development of a natural 

appearing forest, free from any evidence of 

logging, Presumedly the end result is the 

eventual development of old growth or climax 

plant comunity. Presenration is the selected 

objective of many Federal, State, and local 

agencies as well as private organizations 

and individuals. Like any other form of 

management, it has certain impacts upon wildlife habitat. Stand structure and composition 

will vary with climatic and edaphic conditions, 

overstory density, past use, fire history, 

wildlife and livestock browsing, and in the 

case of bottomland hardwoods, flood frequency, 

timing, and duration. Bond (l957), Odum (1950), 
and others have shown that the diversity of 

bird species is maximized at the preclimax 

or middle successional stage and that the 

number of species as well as total number of 

individuals is less at the climax stage. A 

group of forest-dwelling birds such as the 

red-eyed vireo and the cavity-nesting species 

of woodpeckers and owls would probably benefit from preservation objectives. Fire, 

storms, and site differences may create a 

mosaic of stands within a preservation framework. 

I recommend that management adopt the 

following four-pronged approach, and that 

research strive to provide the information 

needed to accomplish this program. 

1. Bring the birds to the people by 

developing habitats in and adjacent to 

recreational facilities and by enhancing 

bird viewing opportunities. 

2. Bring the people to the birds by 

identifying unique birding areas, developing access to good birding spots, and 

educating the people in the art of bird 

appreciation. 

3. Manage for ecosystem integrity by 

enhancing the structural complexity of 

physical and vegetational features of the 

landscape (Table 7), providing a variety of 

habitat components in a desirable combination 

to ensure fulfillment of individual species 

life requirements, and developing a program 

to identify and protect critical habitats of 

endangered, threatened, rare, and unique 

species. 

4. Develop and initiate ways to enhance 

the habitat of the numerous cavity nesting 

species by accepting the idea that dead and 

dying trees are part of the natural stand 

development process, Thinnings should be done 

by girdling or herbiciding instead of felling. 

Regeneration goals could often be achieved 

without removing all dead, dying, and cull 

trees. Rotation age has a major influence on 

the cavity nesting bird species. These 

birds generally require mature forests for at 

least part of their life cycle. Short 

rotation cycles create young, vigorous, fastgrowing timber stands with few natural 

cavities and dead trees. At least part of 

each management unit should be scheduled for 

a long rotation period--in excess of 100 

years throughout the oak-hickory type. The 

pileated and red-bellied woodpeckers are two 

examples of birds that require extensive 

mature forest stands. The barred owls' preferred habitat is an oak woods that is free 

from understory brush and that has many dead 

or dying trees--conditions that are often 

present in over-mature forests. 
Table 7.--A smary of the major habitat components considered in the management programs of 

the Mark Twain National Forest (USDA Forest Service 1973c) 

: Quantitative : Qualitative 

Habitat component : Definition : objectives : objectives Remarks 

Age-size classes The proportion Balance of age- A balance of age- Primarily comof various ages size by compart- size classes by mercial forest 

or sizes repre- ment, 34% sawlogs vegetation types land, managed 

sented ages 44% poles, 11% when adequate under an even0-90; sizes-- saplings, and 11% acreage present age system 

sawlogs , poles, regeneration size 

saplings, & reproduction 

Mast 

Old growth 

Nuts and seeds 40% of the cam- Hardwood vege- A1 1 hardwoods 

from hardwood partment acreage tation types and and hardwoodtrees in mast-produc- species charac- conifer types of 

ing stands (30% teristics of the commercial forest 

for pine com- compartment land and unpropartments) ductive land 

Mature and over- 10% of the com- Vegetation types All forested types 

mature stands of partment acreage and sites repre- and all land 

all types in old growth sentative of classes suitable 

conditions the compartment for growing trees 

Temporary forage Tree reproduction 11% of the corn- Interspersion of All regeneration 

less than 10 yrs. mercial land regeneration areas cuts and type 

o ld managed under among existing conversion areas 

even-age system vegetation types 0-9 years of age 

(12% for pine) and sites 

Permanent forage Areas managed More than 9% of A variety of Forest openings, 

for forbs , the compartment permanent for- grass lands (pasgrasses, shrubs, acreage (more age conditions ture and hay 

or small trees than 8% for pine and areas with- meadows), glades, 

compartments) in compartments upland drainages, 

rights-of -way, 

and savannas 
LImRATURE CITED 

Arend, John L., and Harold F. Scholz 

1969. Oak forests of the Lake States and 

their management. USDA, For. Serv. 

Res, Pap, X-31, 36 p. 

Bond, Richard R. 

1957. Ecological distribution of breeding 

birds in the upland forests of southern 

Wisconsin. Ecol. Monogr. 27(4):351-384. 

Conner, Richard N,, and Curtis S. Adkisson 

1975. Effects of clearcuteing on the 

diversity of breeding birds. J. For. 

73 (12) : 781-785. 

Drew, W. B. 

1942. The revegetation of abandoned 

cropland in the Cedar Creek area, Boone 

and Callaway Counties, Missouri. 

Univ. Mo. Agric. Exp. Stn. Res. Bul. 

344: 3-52. 

Filip, Stanley M. 

1973, Cutting and cultural methods for 

managing northern hardwoods in the 

northeastern United States, USDA, 

For. Sew. Gen. Tech. Rep. NE-5, 5 p. 

Northeas tern For. Exp. S tn. , Upper 

Darby, PA. 

Gingrich, Samuel F. 

1971. Management of young and intermediate 

stands of upland hardwoods. USDA For. 

Serv. Res, Pap. NE-195, 26 p. Northeastern For. Exp. Stn., Upper Darby, PA. 

Griscom, Ludlow, and Alexander Sprunt, Jr. 

1957. The warblers of America. DevinAdair Co., NY, 356 p, 

Nardin, Kimberly I., and Keith E. Evans 

1977. Cavity nesting bird habitat in the 

oak-hickory forests--a review. USDA 

For. Serv. Gen. Tech. Rep. NC-30, 23 p. 

North Central For. Exp, Stn., St. Paul, 

EN. 

Johnston, D. W., and E. P. Odum 

1956. Breeding bird populations in 

relation to plant succession on the 

Piedmont of Georgia, Eeo1,37(1):50-62. 

Kendeigh, S. C. 

1945, Community selection by birds on 

the Nelderberg Plateau of New Uork. 

Auk. 62:418-436. 

Lack, D. 

1933. Habitat selection in birds with 

special references to the effects of 

afforestation on the Brcckland avifanua, J. Anin. Ecol. 23239-262. 

Linehan, J. T., R. E. Jones, and J. R. Longcore 

1967. Breeding bird populations in Delaware" urban woodlots. Aud. Field Notes 

21:641-646. 

Loery , Gordon 

1966, 30th Breeding-bird census, Aud. 

Field Notes 20(6) : 604-634. 

MacClintock, Lucy, Robert F. Whitcomb, and 

Bruce L. Whitcomb 

1977, Island biogeography and "habitat 

islandstf of eastern forest--11. Evidence 

for the value of corridors and minimization of isolation in preservation of 

biotic diversity. Amer. Birds 31(1):6-12. 

Marquis, David A. 

1967. Clearcutting in northern hardwoods : 

results after thirty years. USDA For. 

Serv, Res. Pap. NE-85, 13 p. Northeastern For. Exp. Stn., Upper Darby, PA. 

Miller, A. H. 

1942. Habitat selection among higher 

vertebrates and its relation to intraspecific variations, Amer. Nat. 76: 

25-35. 

Murphy, Dean A., and Hewlette S. Crawford 

1970, Wildlife foods and understory 

vegetation in ~issouri ' sNational Forests. No. Dept. Conserv, Tech. Bul. 

No. 4, 47 p. 

Odum, Eugene P. 

1950. Bird populations of the highlands 

(North Carolina) plateau in relation 

to plant succession and avian invasion. 

Ecol. 31(4):587-605, 

Oosting, K, J. 

1942, An ecological analysis of the plant 

communities of Piedmont, North Carolina. 

Amer. Midl. Nat. 28:l-126. 

Roach, Benjamin A., and Samuel F. Gingrich 

1968. Even-aged sihviculture for upland 

central hardwoods. USDA Agric. Hdbk, 

No, 355, 39 p. 

Wyder, Ronald A., and Audrey Ryder (eds.) 

1976. 29th winter bird-population study. 

Am, Bf rds 30 (6) : 1040- 1075, 

Sander, Ivan L, 

1977. ~anager" handbook for oak in the 

north central states, USDA For, Serv, 

Gen. Tech. Rep. NC-37, 35 p. North 

Central For, Exp. Stn., St, Paul, MN, 

Sander, Ivan %, , and F. Bryan Clark 

1971. Reproduction of upland hardwood 

forests in the central states. USDA 

Agric, Bdbk, 405, 25 p. 
Shelford, Victor E. 

1963. The ecology of North America. Univ. 

of Illinois Press, Urbana, 610 p. 

Shugart, H. N,, S. H. Anderson, and R. H. 

Strand 

1975. Dominant patterns in bird populations of the eastern deciduous forest 

bime. & Smith, Dixie R. (Technical 

Coordinator). Symposium on management 

of forest and range habitats for nongame 

birds. USDA For. Sew. Gen. Tech. Rep. 

WO-1, p. 90-95. Washington, D.C. 

Siderits, K. 

1975. Forest diversity: an approach to 

forest wildlife management. For. Chron. 

51:99-103. 

Slusher, John R., and Thomas M. Hinckley (eds.) 

1974, Timber-wildlife management symposium 

proceedings, Missouri Acad. Sci. 

Occasional Pap. 3, 131 p. 

Smith, Dixie R. (Technical Coordinator) 

1975. Proceedings of the symposium on 

management of forest and range habitats 

for nongame birds. USDA For. Serv. 

Gen. Tech. Rep. WO-I, 343 p. Washington, 

D.C. 

Sprunt, Alexander, IV 

1975. Habitat management implication of 

migration. In Smith, Dixie R. (Technical 

~oordinator)T Symposium on management 

of forest and range habitats for nongame birds. USDA For, Sew. Gen. Tech. 

Rep. WO-1, p, 81-86, Washington, D.C. 

Trimble, George R., Jr. 

1970. Twenty years of intensive unevenaged management. USDA For. Serv. Res. 

Pap. NE-154, 12 p. Northeastern For. 

Exp. Stn., Upper Darby, PA. 

USDA Forest Service 

1973a. Silvicultural systems for the 

major forest types of the United States. 

USDA Agric. Bdbk. 445, 114 p, 

USDA Forest Service 

1973b. Proceedings of the service-wide 

timber-wildlife coordination workshop, 

Asheville, NC, Oct. 30-Mov. 2, 1973. 

USDA For. Serv. Southern Region, 

Atlanta, GA, 154 p. 

USDA Forest Service 

1973c. Wildlife habitat management guide 

for the National Forests in Missouri. 

USDA For. Serv., Mark Twain National 

Forest, Rolla, MO. (Various paging) 

USDA Forest Service 

19 77. The nation' s renewable resources-- 

an assessment, 1975. USDA For. Serv. 

Res. Ref. No. 21, 243 p. 

Verner, Jared 

1975. Avian behavior and habitat management. In Smith, Dixie R. (Technical 

~oordinzor) . Symposium on managernen t 

of the forest and range habitats for 

nongame birds. USDA For. Serv. Gen. 

Tech. Rep. WO-1, p. 39-58. Washington, 

D.C. 

Webb, William L,, Donald F. Behrend, and 

Boonruang Saisorn 

1977. Effect of logging on songbird 

populations in a northern hardwood 

forest. Wildl. Monogr. 55:35. 

Zeedyk, William D., and Keith E. Evans 

1975. Silvicultural options and habitat 

values in deciduous forests. In Smith, 

Dixie R. (Technical ~oordinato3. 

Symposium on management of forest and 

range habitats for nongame birds, USDA 

For, Serv. Gen. Tech. Rep. WO-1, 

p. 115-127. Washington, D.C. 
Cove Forests: Bird Communities and Management Options 

1" Robert E. ~oope& 

Abstract.--Over 60 species of birds regularly nest in 

cove forests. A primary goal for rnanaging nongme birds is fa 

provide suitable habitat, at soae stage of the rotation, for 

each species that naturally occurs in a forest ty-pe. Evenaged stands up to 25 acres and rotations of 100 years should 

meet that goal in cove forests. Commercial thinnings benefit 

shrub nesting species but remove potential sites for cavity 

nesters. 

INTRODUCTION 

The forests of mountain coves, ravines, 

and adjacent moist slopes of the Southern 

Appalachians are mong the most productive 

hardwood ty-pes of the North Temperate Zone. 

They have great esthetic value, protect water 

quality, and are of considerable botanical 

interest. Depending upon stand age and species composition, these forests provide habitat for many species of birds. In this 

paper I review existing infomation on breeding communities of birds in cove forests and 

predict possible effects of forest management 

options on these communities. Cove forests 

also may be important to winter bird populations, but data are lacking for an interpretation. 

THE COVE FOREST 

Cove forests are found at elevations 

between 1,000 and 4,500 feet in the Southern 

Appalachians of Virginia, Tennessee, North 

Carolina, South Carolina, and Georgia. They 

occupy coves, ravines, and adjacent moist 

lower slopes. An estimated 3.5 million acres 

of cove forest exist in the Southern Appalachians (D. E. Beck, pers. commun.). Some 30 

tree species occur in cove forests; 6 to 8 

may be prominent in any particular stand 

(~raun 1-96?, p. 199-205; Davis 1930; 

Whittaker 1956). At least 10 of these species are considered of high commercial value 

(table 1). 

Various forest cover types have been 

recognized in coves (table 2). These types 

l/ Research Wildlife Biologist, U. S. 

Dep. Grit., For. Serv., Southeast. For. Expt. 

Stn., Cfemson, S. C. 

grade into oak, oak-hickory, and oak-pine 

types on relatively dry sites. At high elevations, cove forests give way to northern 

hardwoods and spruce-fir. He%Zock commonly 

dominates an floors of ravines at all elevations and on broad valley Plats around 4,000 

feet above sea level. 

Underston conditions vary tremendously: 

both open parklike and extrmely dense understories occur. Rosebay rhododendron (Rhodo- 

) generally forms dense understories near strems and beneath halockdominated stands. In stands which are predominately hardwood, a Large variety of shrubs 

and small trees occur in the understor;y. 

Many stands with an open understory have a 

lush herbaceous layer ( Cain 1943 ) . 

While stands at or near climax contain 

primarily tolerant species--sugar maple, buckeye, hemlock, and beech (table 1)--even the 

intolerant but long-lived and fast-growing 

yellow-poplar occurs sparingly o ow ells 1965, 

p. 261 1. Climax stands are normally dominated 

by several species. 

AIL of the 62 species of birds known to 

nest in the different sera1 stages of cove 

forests (table 3) eac be found nesting in 

other forest types in the Southern Appalachians or ia other physiographic regions. Some 

stands have an uri;sually large number of species (table 41, but the average cove forest 

does not have nore species than other types 

in the Southern kp2alachians (~zwer 1950). 
Table 1.--Major tree species of cove forests 

Species 

Potent ial 

conilnerc ial 

value 

Tolerance to 

competition 

yellow-poplar (Liriodmhon tulipi,"era) 

Basswood {Tiiia spg. 

Black cherry (*&nus serotina) 

Black walnut (JugZans nigraf 

White ash (i*p?axinus merieanaj 

bihite oak (&ereus aZbal 

Northern red oak (&. rzlbraj 

Cucumber tree (Magnolia anvninatal 

Sugar maple lAeer saeeam) 

White pine (Pinus strobus) 

Sweet birch BetuZa Zenta) 

Black locust (Rubina pseuduaeaeia) 

Chestnut oak (&. prinus) 

Hickories (Carya spp. ) 

Yellow buckeye (AeseuZus oetandra) 

Beech ( Fagus grandifulia) 

Red maple (A. mbm) 

Yellow birch (23. Zuteaf 

Fraser magnolia (Ma_anoZia Fraseri) 

Silver bell (NaZesia rnonticoZa) 

Hemlock (Tsuga eanadensis) 

Blackgm (Nyssa syluatiea) 

High 

Iiigh 

High 

High 

High 

High 

High 

High 

High 

High 

Medium 

Medium 

Medium 

Medium 

MediumLow 

Low 

Low 

Low 

Low 

Low 

Low 

Intolerant 

Tolerant 

Intolerant 

Intolerant 

Intolerant 

Intermediate 

Intermediate 

Intermediate 

Very tolerant 

Intermediate 

Intolerant 

Intolerant 

Intermediate 

Intolerant 

.low Tolerant 

Very tolerant 

Intermediate 

Intermediate 

Intermediate 

Tolerant 

Tolerant 

Intolerant 

Table 2.--Forest cover types of coves, ravines, and adjacent moist slopes in 

the Southern Appalachians 

SAF 

typeL/ 

R-8 Wildlife habitat 

management andbook 

type- 27 

R-8 Timber 

manage. types/ 

Yellow-poplar-white oak- Yellow poplar-white oak- Yellow poplar-white oaknorthern red oak northern red oak northern red oak 

Yellow-poplar-hemlock White pine-yellow poplar- White pine-yellow poplar 

hemlock 

Hemlock 

White pine-hemlock 

Northern red oakbasswood-white ash 

Yellow-poplar 

Hemlock 

- I/ Psion. 1967. Forest cover types of North America. Soc. her. For., Washington, 

D. C. 

- 2/ Ancn. l93l. Wildlife habitat management handbook. U. S. Dep. Agric., For. 

Serv., Region 8, Atlanta, Ga. 

- 3/ Anon. 1912. Compartment prescription field book. U. S. Dep. Agric., For. Serv., 

Region 8, Atlanta, Ga. 
Table 3.--3elative value of sera1 stages of cove forest as nesting habitat" 

Virgin Second-Growth -- .,- Species T.--% - n--'?z-- nar6wooG.s nemloc'r; Saw lLii2it.t vie uaplLlrg 

Broad-winged Hawk X 

Ruffed Grouse X 

Yellow-billed Cuckoo 

Screech Owl X 

Barred Owl 

Common Flicker X 

Pileated Woodpecker XX 

Hairy Woodpecker X 

Domy Woodpecker X 

Great Crested Flycatcher 

Eastern Phoebe 

Acadian Flycatcher X 

Eastern Wood Pewee 

Blue Jay X 

Black-capped Chickadee X 

Carolina Chickadee 

Tufted Titmouse X 

White-breasted Nuthatch 

Red-breasted EJuthateh 

Brown-creeper 

Winter Wren 

Carolina Wren 

Gray Catbird 

Brown Thrasher 

American Robin 

Woodthrush 

Veery 

Blue-gray Gnatchatcher 

Golden-crowned Kinglet 

Cedar Waxwing 

White-eyed Vireo 

Yellow-throated Vireo 

Solitary Vireo XX 

Red-eyed Vireo XX 

Black-and-white Warbler X 

Swainson's Warbler 

Worm-eating Warbler X 

Golden-winged Warbler 

Northern Parula X 

Black-throated Blue Warbler XXX 

Black-throated Green Warbler XX 

Blackburnian Warbler X 

Yellow-throated Warbler 

Ckestnut-sided Warbler 

Pine Warbler 

Prairie ijarbler 

Cwenbird 

Lcuisiana Waterthrush 

Common Yellowthroat 

Yellow-breasted Chat 

Kooded Warbler 

Canada Warbler 

Scarlet Tanager 

Cardinal 

Rose-breasted Grosbeak 

Indigo Bunting 
Species 

71- Y lrgin . Second-Growth 

Kardwoods Hemlock SawtLmber Pole Sapling 

Jmerican Goldfinch X X 

Fufous-side3 Towhee X X :a 

Dark-eyed hneo ?a "RX XX 

Chipping Sparrow )I X 

Fleld Spmow X X 

Song Sparrow X )r?(3i 

- I/ X = Species occurs at low frequencies and decsities. Also occ71rs ir, 

other habitats at greater densities. 

XX = Species occurs at medium densities but also occurs at equal or 

greater densities in other habitats. 

-XXX = Species occurs at highest densities within the region. 

table is based on literature cited in the text and personal obseraation 

by the author. 

I Table 4.--~ensities and numbers of species of birds in cove forestsBird 

Stand condition density Number of TJumber of 

(pairs/l00acres f species censuses 

Seedling and 

sapling 

Poletimber 

Sawt hber 

Virgin 

Bemlock 

Hardwoods 

- I/ Values in table taken from literature cited in text. 

A l-year-old clearcut had 46 pairs of breeding 

birds per 100 acres (~ewis and Smith 1975). 

The mean for all other cove forests reported 

(~awer 1950; Hclt 1914 ; F4el l inger 1969-1975, 

1977; Odum 1950) was 314 pairs per LOO acres, 

and the highest was 510 pairs per 100 acres. 

These densities are greater than for other 

forest types in the Smoky Mountains [~awv-er 

1950) and for most other forest types in the 

South and Southeast . 

Virgin Stands 

FaWer (1950) eensused four virgin cove 

forests that were dominated by hardwoods and 

two that were dominated by heznloek. Cdm 

f 1950) and Kolt (1974! censused a virgin hemlock stand at a 12-year interval. Densikj of 

pairs of breeding birds per 100 acres ranged 

from 183 to 370 in the hardwood stands and 

from 230 to 430 in the hemlock stands (table 

4). The virgin hardwood areas had 13 to 23 

species of breeding birds and the virgin hemlock had 9 to 18 species. A total of 28 species nested In the virgin stands. Each of 

these species nests in other habitats, bo-tb 

in the region and in other regions. 

Species aost dependent on virgin stands 

appear to be the Elack-throated Blue Warbler, 

Black-throated Green Warbler end Blackburnian 

Warbler. Although these species occur in 

seral stages of the cove fcrests and in other 

forest tj~es, they reach high densities in 

the virgin cove forests. The Black-throated 

Blue Warbler was the most abundant species in 

the hardwood-dozinated cove forests, accounting for up to 59 percect of the density of 
breeding indivldrrais: one area had 185 breeding pairs per 100 acres (F~w-er 1970:. Although densities of the Biack-throated Blue 

Warbler were less in hemlock-dominated fcrests, it was still an abundant species. The 

Blackburnian Warbler and the Black-throated 

Green Warbler were associated aostly with 

hem2oek stands, 

Twelve cavity nesters used the -sirgin 

stands but were usually xore ab~ni-lant in the 

second-growth stands, 

Sesond-Growth Stands 

gellinger (1969-75, 1977, pers . comun. 

censused a mature satstimber stand for 9 consecutive years. Odm (1950) and Holt (1974) 

censused a poletimber stand in 1946-47 and 

in 1959-60; thef revisited the stand in 1971- 

72 when it was in a sawtitrber stage. They 

also censused a stand in the sapling stage in 

1946-47 and 1959-60, and again in 1971-72 

when in a pole stage, Lewis and Smith (1915) 

censused a stand 1 growing season after clearcutting. 

Population density and number of species 

in the second-growth pole and sawtimber stands 

were similar to those of the virgin stands 

(table 4). Bird species found in the virgin 

stands were well represented in the secondgroTcrth saw-timber stands (table 3). The second-growth stands did not have the high densities of Elaek-throated Blue Werblers that 

Fawer (1950) reported for the virgin stands. 

Holt (1974 ) found 44 pairs of Black-throated 

Blue Warblers per 100 acres--the highest reported in second-grodh stands, 

The pole stands had surprisingly large 

bird populations (table 4)" This abundance 

may have been due to a light stocking of 

trees, the occurrence of hemlock, and a welldeveloped rhododendron understory ( Odum 1950 ; 

Holt 1974). Pole stands of yellow-poplar and 

other hardwoods would probably have much lower 

densities. 

The coxposition cf bird species was considerably different in sapling plots than in 

older stands (table 3 1, For exaple, Od1m 

(1950) reported a percentage difference (which 

takes into account the bund dance of each species) of 91.9 between a sapling and a virgi~ 

stand. 

~972)~ At 83 years, well-stccked stands of 

second-growth hardwoods contain about 31,000 

Foard feet per acre on the best sites and 

25,000 board feet per acre on lower quality 

sites (~rothingh~ 1932 1. 

Sfnce the majority of desirable tirn5er 

species are rziati-vely ictolerant of conyeLion (table 1), cove forests are generally 

managed for timber under even-aged silvicultural systems (Trirnble 1973 1. 

The individual selection silvicultural 

system, leading to all-aged stands, nay be 

used where disturbance to the canopy rirust be 

minimized to protect esthetic values or 

stream banks. Because selective cutticg favors tolerant species like buckeye, hemlock, 

beech, and sugar maple, it may reduce stand 

diversity. Of the tolerant species, only 

sugar maple and basswood have high comercial 

potential. Selection cuts heavy enough to 

encourage regeneration of intol-erant species 

may result in understocked stands and highgrading (~rimble 1973 ) . 

Group selection cuts as small as 0.25 

acre can regenerate the intolerant species, 

but openings of 0.5 to 1.0 acre are more desirable for gromh of the regeneration 

(~rimble 1973). However, the impact of deer 

browsing upon the reproduction can be severe 

in openings that small (~arlow and Do'ivaing 

~969 1. 

Shelterwood cuttings are silviculturally 

feasible and could be used to maintain a forested canopy. The shelterwood system may be 

especially- suited to securing advanced regeneration of heaqr-seeded species such as oaks. 

The seed tree method is unnecessary in cove 

forests because many of the hardwoods sprout 

readily, advanced regeneration is normally 

present, and the light seeds of certain species carry long distances C~rimble 1973). 

Clearcutting offers the greatest potential for intensive timber management. bIaximum reproduction and growth of the desirable 

timber species are provided under this system 

(~rimble ~973). Clearcuts as small as 1 acre 

(essentially overlapping the group selection 

system) can be used. Silviculturaliy there 

is no upper size limit for clearculs, but on 

forests under multiple-use management upper 

size limits are imposed to enhance wildlife 

and other values. 

TIMBER VJ9NAGB3PJT PFACTICES Rotation length for rnaxinmm wood production is about 70 years for yellow-poplar Cove sites are highl.~ productive and are and 80 for oaks. Most landomers use rota- t~ypieally classed as good to excellent for tions of 70 to lOD years. The National For- timber growth, Oaks grow 65 to 90 feet and ests currently use 100-year rotations to en- yellow-poplar grows 90 to 140 feet in 50 hance scenic val3~es. 

years (Trimble 1913; Beck and Della-Bianca 
Precomnereial xkincings increase growth 

rate and improve stand compositioc and stem 

distribution. Such treatxents are costly, 

however, and gains mst be kigh to jastify 

there, Production QP palatable browse may be 

a parGial Justification for preco;mr~ereial 

thinning e el la-~iaaca 1975 1 . Oc some areas, 

there is a nee3 %o release c-op trees from 

grapevines (~c~ee and Kcoper 1975). Rosebay 

rhododendron is so 2ense ic some areas that 

it severely inhibits tree regeneration, but 

no practical mans of ecntro; Is available 

 el la-~iaaea and WcGee 1972 1. 

Stands containing high percentages of 

yellotr-poplar are usually quite dense, and 

wood fiber yieZds are highest when these densities are maintaiced. If the maJor goal is 

to enhance growth of saw Logs and veneer 

bolts, however, periodic thinnings are required. A rule of thumb for maximum boardfoot growth in thinned stands 30 to 70 years 

old is to match residual basal area to site 

index, e.g., 90 sqcare feet basal area on 

site 90 and so on (~eck and Della-Bianca 

(2.975). 

IJANAGmNT IMPACTS AM3 RECOPaBTJBATIOWS 

Goals 

If a manager wants to encourage birdlife, 

his goal should be to provide suitable habitat 

for each indigenous species for some period 

during the timber rotation. Further, he should 

ensure that these sets of conditions are always 

present at some point in the forest. Any 

practice that alters yJ-eaetation will benefit 

some species of birds and be detrimental to 

others. It is impossible to have all bird 

species nesting in the same stand at the same 

time, but suitable habitat conditions for each 

species can be provided in some part of the 

forest all the time. This approach will provide for more bird species than any attempt 

to maximize the species and bird density on 

each acre. 

3ecomendations for bird manegement are 

provided below. These reconmendations are 

based on the best available information. Tney 

are, hoxever, largely untested. 

Rotation D,ae 

Rotations of 100 yeers seen adequate to 

pro-ride h~tbitat for the bird speeies associated with virgin stands. Specific studies on 

stand age as it relates to bird co~~tlunities 

in coyre forests are lacking, but none of the 

second growth stands reported were greater 

than 100 gears old. Certain species, such as 

the Black-throated Blue Xarbler, Earred Owl, 

and Pileated Woodpecker may require locger 

rotations for hakitat conditions apprcachicg 

their ogtimm. 

Shorter rotations of say 70 to 8G yeers 

~ay provide habitat for most, if not all, of 

the species that were found i~ vlrgin stands, 

but some of these speeies would probably be 

existing under marginal ha'bitat conditions 

that have unknown imparts on the speeies. 

Stand Regeneration 

Clearcutting 

Clearcuts as srriall as 1 acre will provide habitat for all the species in table 3 

listed under che Second-Growth Sapling Stage 

except the Prairie Warbler, Yellow-breasted 

Chat, and Field sparrow. These three species are by far more abundant in the early 

seral stage of the oak-hickory and oak-pine 

types adjacent to the eove types so they 

would not be eliminated from the forest 

f ~ooper 1967 ) . 

Larger clearcuts of say 25 acres would 

provide suitable habitat for larger and less 

fragmented populations of the early seral 

species. Birds requiring mature stands would 

be better provided for, in the long run, by 

the larger clearcuts since the older stands 

would also be larger in area. Clearcuts exeeeding 30 acres in cove forests seem unneeessary in managing bird populations: all species using sapling and mature stands should 

find habitat in stands of that size, 

Shelterwood Cuts 

Shelterwood regeneration areas with a 

residual basal area of 40 to 50 sq-ir;are feet 

per acre would probz;bly provide habitat for 

most of the species of the sapling stage. 

Species using edge habitats, such as Chestnut-sided Warblers and Indigo Buntings would 

be especially attracted to shelterwood areas. 

Some of the species of the mature forest 

would continue to use the shelterwood area 

until the residual trees were removed. Gue 

to the layering of the vegetation, a larger 

nmber of bird species would be expected on 

these areas than on the elearcut areas. 

Group Selection Cuts 

Group selection cuts approaching I acre 

would have effects similar to the smallest 

clearcuts discussed a'bove. Smaller cuts of 

0.25 to 0.70 would probably have effects 

similar to the individual selection cuts discussed below. 
Individual Selection Cuts 

Individual selection cuts with a residual basal area of 80 square feet or less per 

acre and group selection cuts of 0.25 to 0.50 

acres would probably result in high densities 

and numbers of species. Species requiring 

either a continuous canopy or sparse canopy 

might be at a disadvantage under these conditions 

Thinnings 

Comercia1 thinnings on these good sites 

result in prolific growth of the understory 

(D. E. Beck, pers. comun.). Both the number 

of species number of individual birds 

should increase (~ooper and others 1973) following thinnings. 

Thinnings, and possibly individual and 

group selection cuts, could have a severe impact on the Pileated Woodpecker. Pileated 

nest trees in Virginia (canner and others 

1975) were on mesic sites and in stands with 

an average basal area of 137 square feet per 

acre. Most nest cavities were in dead trees 

or in dead portions of live trees. Such trees 

are usually removed in thinnings. Although 

pileateds have territories of 100 to 200 

acres and larger, leaving as little as 1 acre 

per 100 acres of cove forest unthinned (but 

regenerated in the normal rotation) could 

greatly improve conditions for the pileated 

and other woodpeckers in intensively managed 

cove forests. Thinning in the usual manner 

but girdling and leaving several of the less 

valuable trees might be a more economical alternative. 

LITERATURE CITED 

Beck, Donald E., and Lino Della-Bianea. 

1972. Growth and yield of thinned yellowpoplar. USDA For. Serv. Res. Pap. SE-101, 

20 p. Southeast. For. Exp. Stn., Asheville, R. C. 

Beck, Donald E., and Line Della-Bianca. 

1975. Board-foot and diameter growth of yellow-poplar after thinning. USDA For. Serv. 

Res. Pap. SE-123, 20 p. Southeast For. 

Exp. Stn., Asheville, R. C. 

Braun, E. Lucy. 

1967. Deciduous forests of eastern North 

America. 596 p. Hafner ~abl. GO., ~ew 

York . 

Cain, Stanley A. 

1943. me tertiary character of the cove 

hard-wood forests of the Great Smoky P4ountains National Park. Bull. Torrey Bot. 

Club 70:213-235. 

Gonner, Richard ti,, Robert C. Hooper, Hewlette 

S. Crawford, and Henry S. Mosley. 

1975. Woodpecker nesting habitat in cut and 

uncut woodlands in Virginia. J. Wildl. 

Idanage. 39 : 144-150. 

Davis, John H. 

1930. 'Jegetation of the Black Mountains nf 

Worth Carolina: ecological study. 3. 

Elisha Mitchell Sci. Soc . 45 : 291-318. 

Della-Bianca, Lino. 

1975. An intensive cleaning of mixed hardwood sapling - IC year results from the 

Southern Appalachians. J. For. 73:25-28. 

Della-Bianca, Lino, and Charles E. McGee. 

1972. Reaction of natural Rhododend~~on 

mmh L. to liming in the Southern Appalachians. J. Elisha Mitchel-l Sci. Soc. 

88:1O9-112. 

Fawver, Ben J. 

1950. An analysis of the ecological distribution of breeding bird populations 

in eastern North Axlerica. Ph.D, thesis. 

199 p. Univ. Ill., Urbana. 

Fowell-s , H. A. 

1965, Silvics of forest trees of the United 

States. USDA For. Serv., Agric. Handb. 

271, 762 p. 

Frothingharn, E. H. 

1931. Timber growing and logging practice 

in the southern Appalachian region. USDA 

Agric. Tech. Bull. 250, 92 p. 

Harlow, Richard F., and Robert L. Downing. 

1969. The effects of size and intensity 

of cut on production and utilization of 

some deer foods in the Southern Appalachians. Trans. 26th Northeast. Fish and 

Wildl. Conf., Northeast. Sect. Wildl. Soc., 

P. 45-55. 

Holt, Jane P. 

1974. Bird populations in the hemlock sere 

on the Highlands Plateau, North Carolina, 

1.946 to 1972. Wilson Bull. 86: 397-406. 

Booper, Robert G . 1967. The influence of habitat disturbances 

on bird populations. 14.S. thesis, 134 p. 

Va. Polytech. Inst., Blacksburg. 

Hooper, Robert C., Hewlette S. Crawford, and 

Richard F. Harlow. 

1973. Bird density and diversity as related 

to vegetation in forest recreational areas, 

J. For. /1:766-769. 
Lewis, Richard 7., and Alan E. S~ith. 

1915. Tnirty-nLnth br~edicg blrd census: 

Deci&~ous clearcut. A%, Birds 25:iLi7- 

i118, 

!$ellinger, E. C. 

1974, Thirty-eighth breejing bird census: 

Mocntain ravine mixed forest. kli. Birds 

28 : 1005. 

McGee , CkarLes 5, , an5 Ralph 14. Xocper, 

1975. 3egenerati.cn +rends IC years after 

clearc-zt~icg 6f ac A~palschien har&doad 

stand. U89-A 7~r. Serve Pes, S3te SE-227, 

12 p, Southeast. For. &p. Stn,, Asheville, N. C. 

MelLinger, E. 0. 

1969. Tlirty-third breeding bird census: 

Mountain ravine rnixed f crest. Au&;bon 

Fi eld Rotes 23 : 11-2 , 

Mellinger, E. 0. 

1970. Thirty-fourth breeding bird census: 

Mountaic ravine mixed forest. A?~&!ubon 

Field Notes 2b:748. 

Mellinger, E. 0. 

1911- Thirty-fifth breeding bird census: 

Mountain ravine mixed forest. Am, Eirds 

25:975. 

Mellinger, E, 0. 

1972. Thirty-sixth breeding bird census: 

Kountain ravine mixed forest. Am. Birds 

26:953. 

!*leilinger, E. C;. 

1975. Thirty-ninth hreeiizg bird census: 

:tountain ravine mixed forest. h. Blrds 

29:1993--109L. 

Tilellinger, E. Q. 

1941, Fortieth breeding bird eer-sus : P4ountain ravine mixed forest. Ax. Birds 31: 

h2. 

Odm, &gene P. 

1970. Bird popuiations of the Highlands 

(~orth ~arolina) Plateau in relation to 

plant succession and avian invasion. 

~cologj 31 : 507-605. 

Trimble, C. R. 

1973. Appalachian nixed hardwoods. p. 80- 

82. In Silvieultural Systems for major 

fgresny-pes of the United States. USDA 

For. Serv., Agric, Eandb. 445, 114 F. 

Whittaker, Robert B. 

1956, Vegetation of the Great Srnokey Pqfountains . ~co~. ~onogr . 26 : 1-89. 

Meilinger, E. O. 

1973, Thirty-seventh breeding bird census: 

PIountain ravine mixed forest. An. Birds 

27 :941. 
A Comparison of Avian Csrwmarnirfy Structure in the Northern and 

Southern Appaiackian Mountains 

2/ Barry R. soon&' and Kenneth P. Able-- 

Abstract.--The structure of avian cornunities along elevational gradients is examined. A descriptive analysis of calnrnmity-lev& properties, contrasting northeastern and southeastern 

commities, ia presented. Hypotheses sufficient to explain 

differences in cornunity orgmization are gregosed and examiaz.ed 

by malysfs at the popdation-level. Eaphasis is placed on 

shi fts in species habitat utilf zat ion sr~bsequent to ehages in 

species cogt~?osition and h& itat availability. Suggest ions for 

the development of workable habit at mnagenect schemes are 

preasnted. 

Numrous studies have recently bean conducted in an attempt to understand niche patterns within animL commit ies, the correlations between various niche dimnsiona and 

species diversity, and the contribution of 

critical dimensions to achie~ng species coexistence. Hany of these studies have dealt 

explicitly with the importwee of habitat 

usage in eco1ogicaL comunities, particularly 

bird connnunit ies (%cArthur and %cArthur, 

1962; MacArthur et al. , 1966; 60d.g~ 1968; 

Miens, 1969; Jams, 1971; Shugart ad Patten, 

19 72; Anderson and Shugart, 19 74; h%itmre, 

1977; and orhers). Of particular relevance to 

this symposium ie the almost unaninraus consensus thar bird species diversity is strongly 

correlated with structural habitat diverstty 

and that for the majority of species there is 

a cause and effect relationship between these 

variables. 

acftrkhur and hia coworkers initially est&lished the inrgortance of habitat structure 

when they discovered the strong positive eorrelation between foliage height diversity, an 

I/ Much of the data Ear this paper tas 

colle<ted while this author was a graduate 

student in the BioloB Department, State University oE New York at APbmy, Albmy, 1:g'll. 

Present address: Nw York State Bepartmnt sf 

Health, Birth Defects Lnetitute, Epidemholog 

and Humg EcoZog3r. 

21 hspciate Profassur, BdoPegy Departmeq$,-~~ate Lkiversity of Vew 'Imk at Albany, 

Albany, New Ysrk. 

hdex of the vertical distribution of foliage 

biomass, and species diversity (1.fadrthur iurd 

MacArth~r~ 1361; Mac4rthur and Preer, 1962) . The major sipfficanee sf this finding was 

that a single index was such a powerful predictor of s3ecies diversity in a variety sf 

geographically distinct locales. 

FoZLwing Y~cArth~r 

studies aimed at mderstanding the connection 

between habitat structure and species diversity 

have been conducted (reeewed in Balda, 19 75) - 

In recent studles there has been a movement 

away from aslalyses of single habitat variables 

tovards multivarfate analyses of habitat data 

(i.e., Shugart ad Patten, 1972; k%itmore, 1977). 

The eomplexit:~ has been expaded prlmrily for 

two reasons: 1) to ~nderscand bird species 

d iverstey patterns in those cornunities for 

whickx foliage height diversity (and other indexes such as pereenr vegetation cover) had not 

been a good predictor (i.e., Balda, 1959; Karr, 

$971; Pearson, 1875; WilBon, 1974j ; and, 2) to 

discover the specific features sf habitar structure which were contuiblating to species diversiq* 

From studies sf a-jian com*mit ies occupying 

temperate forests, some general patterns of reseurce partitioning have ezerged. The most important sf these is that habitat selection is 

the daminat factor determining bird distribut ions ad habit at features are more import ant 

than fwd availability in avian resource division QSchoener, 1974; Shugart et ale, 1975). 

Further, a revlew of multivariate studies of 

habitat partitioning i~ forest bird commit&es 

(Jams, 1971; Shugarz and ?atten, 1972; Shugart 

and James, 1973; Aaderson and Shugart , 1974; 

Wkitmre, 1995, 1973) reveals a consistently 
darnhat role for a small subset of stmctoxa$ 

habitat variables. The exgensive discriminatew power contained 3x1 ,just a few variables 

is best illmtrsted by mitg~gre (1973) who nas 

able to sigrrificmtly separate a commity of 

24 species by considering only 10 habitat 

variab las * 

The consistency apparent in these findings indicates that a few structural features 

of the habitat may be the dominant deter~nants of species diversity* Further, they argue for a general pattern of forest cornunity 

organization independent of geographical locatgon within the teglperate zone. '&"ha unique 

features sf temperate aviarr species which result in regular patterns of cornmity organization my primarily be a censequence of the 

migratory nature of the riJ oxity of breeders, 

These characteristics and t heir implications 

for the evolution of strong habitat selection 

have been discwsed by Able and Noon (1976). 

In the discussion kshieh follows we will, 

examine the organizat don of eastern mntane 

forest bisd comunities. We will first present a descriptive analye is of commity-level 

properties, comparing nartheaotern and southeastem rsnthe cornunities . From the~e 

analyses we generate hypotheses about cow 

munity structure that are sufficient to explain differences in eomunity-lavel organization. As a test of our hypotheses we will 

present results of a populat ion-level malysis 

of a subset of these avian cornmitias. We 

examined the ground-foraging thrush guild vhich 

particularly in tha Northeast, is s daznlnant 

component of these Pnontme comunities. Fle 

conclude by smthesizing the results of both 

the cornunity md papulation-level studies 

into a tencltive scheme for habigat 

mcsnt which, hopefully, will maintain the integrity of natural bird comuniries . 

Species Biskribut ion Patterns 

On the northeastern and southeastern 

study sites sampling stations were established 

approximtely every l0Om along the eletaational 

gradient:. Censusfng data was collcacted during 

a 3 - 4 hr interval begiming imediately after 

dam and again in rhe lake evening I - 2 hr 

prior to sunset. At: each sampling station two 

observers walked in opposite directions recording all bird species seen or haard while 

progressing at a steady pace for a prescribed 

length of time (usually 5 - 75 hr) . On suecessive days the order in% vhicS1 stations were 

sampled Gas altered so as ts mini~ze bias 

introduced by ti= sf day. In general, 1.5 - 2 hr of sampling time was aecumlaked for each 

saqling station. Finally, the counts were 

nomalized tg the nu&er of individuals of 

each species per hour of sanplhg time at each 

station (see able and Hoon 1976, for further 

details). 

Habitat hafyses 

The habitat data quantifyhg the structural 

pararueters of the thrush species ' territories 

were obtained by sampling 0.04 ha (0.1 acre) 

circular plots centered upon the point at which 

a bird was seen perfor~ng a specified behavior. 

Tho sampling methods closely followed quantif ications techniques proposed by James and Shugart 

(1970) . The desim of the techniques is such 

that all strata of the forest breeding habitats 

are thoroughly measured. 

A total of 250 habitat quantifications was 

done on the five thrush species at the northeastern montane site, 94 quantifications were 

obtained on two thrush species at the southeastern montane site and 56 quantifications were 

done in a nonmontane site in northern New York. 

No attempt was made to stay within homogeneow 

stands of forest when sampling but all samples 

were collected so as to avoid "edgef' situations. 

All, habitat quantifications at both montane 

sites were done to include habitats covering 

the full range of a species\levational distribution. In addition, the sampling intensity, 

as a fmction of elevation, reflected the distributional abundance of the species along the 

elevatioml gradient. 

Study Areas 

The northeastern rnctntane study area was 

%unt &nsfield, the highest mountain in the 

Green Mountains of Vermont, with an elevation 

of 1339x11. The mountain is located approximately 

65 km east of Burlington, Vermont (44' 31'~, 

84' W) . The study site covers an area sf approximately 10 km2 on the eastern face of the mountain. 

Relatively wdisturbed forest extends from 

5SOm to 1200111, the last 200m of elevation being 

alpine =adow rand ewosed rock. The eastern exposure of the mountain is criss-crossed with 

nuwrous ski trails; however, they have had a 

negligible effect on the cornposit ion, abwndance 

and distribution of the avian populations (Able 

and Noon, 19 76) . The extent of the edge effect 

between ski trail and usldisturbed forest is 

slight zsnd we avoided areas of e-ensive disturbmce in all cases. The vegetation of the 

mountain is basically mture second growth 

forest, although sme areas of virgin sprucefir remain at high elevations (Siccam, 1968). 

The mountain is composed of four major vegetat ion zones. Successively , these zones are : 

le (Aeer saecharuzn) and beech ( 

forest; 2) yellow birch (Betul 

and red 
spruce (Picea rubens) forest; 3) red spruce 

and balsam fir (Abies balsami), and 4) alpine 

tundra. 

To the casual observer the mountain gradient appears to consist of at least two discrete vegetation& units: pure deciduous and 

pure coniferous with a zone of mixed vegetat ion at ~d-elevat ions. However, Siccaa 

(1968) showed that the mgatation of the Green 

lilountains is actually a complex continuum of 

species populations rather than a mosaic of 

discrete cornunities (see mittaker, 1367) . Deciduous forests characteristic of the low 

elevation forests are not found above midelevations, but species characteristic of 

uppar slopes are found in small numbers on 

the lower slopes. In the zone between the 

two maj or vegetational units species characteristic of both occur, but no species is confined to mid-slope forests. Despite the 

essential continuity which characterizes the 

vegetational commity of this gradient, we 

have distinguished three maj or changes in 

vegetational physiomomry: 1) the area on the 

gradient in which beech and sugar maple disappear. Concomitantly , yellow birch and red 

spruce increase markedly. 25 the virtual 

disappearance of deciduous trees along with 

an increase in the proportion of balsam fir. 

3) tree line. In practice, ecotones 1) and 

2) could be localized within zones of about 

100m of elevation or lass, and tree line was 

considerably more abrupt. 

The southeastern montane study area was 

the Great Smoky Mountains National Park located on the border between Tennessee and 

North Carolina (83' 37'~, 84' 30'W). This 

montane site covered an elevational gradient 

extending up to 2025m on Clingman's Dome on 

the Tennessee side of the main mountain ridge 

The gradients studied had primarily a north 

to north-northwest exposure and for the most 

part were characterized by =sic to submesic 

forest types. 

The Great Smoky Mountains supports a particularly diverse forest of varied community 

types. kJhittaker (1952, 1956) gave an exhaustive description of the forest cornmities. In general, the vegetational comunities in which studies were done are of three 

major types: 1) msic cove forests; 2) submesic oak forests; and 3) subalphe forests. 

In the =sic cove forests the principal 

canopy trees were y ellog buckeye (AescuZus 

octandra) , white basswood (Tilia >, 

silver"beP1 (Eolesia wnticola), sugar maple, 

eastern hedock ( canadensis), tulip tree 

(Liriodendron tulipifera), yellott birch and 

beech (Whittaker, 1952, 1956). Above 1370m 

the conrposition of the wsic forest changes 

into a subalpine forest dowinated by red spruce 

and Fraser fig (A. fraserii). Outside of the 

range of the spruce, or where ravhes cut into 

the momtab ridge, mesic stads above 1370m 

are do~nated by gray birch. 

In spite of the fact that this transeet, 

like the northeastern one, is also a complex 

continuum of species and not easily divisible 

into discrete vegetational eomunities, two 

ecotones were recomized: 1) the area on the 

gradient in rJhich red spruce a~d yellow birch 

become significant components of the canopy, 

This zone is characterized by a substantial 

decrease in canopy height. 2) the virtwk disappearance of deciduous trees along with an 

abrupt increase in the percentage of red spruce 

and the appearance of Fraser fir. Both ecotona 

correspond with areas where gross changes in 

the structural physiognomy of the Eores t 

occurred. 

The non-montane northeastern study site 

included the islands and shoreline areas on the 

Cranberry Lake Biological Station, Saint 

Lawrence County, New York (44' 15'~~ 7 4" 45'~) . The study site covered an area sf approximtely 

14 km2. 

Relatively mdisturbed second growth forest covered most of the areas studied, though 

some areas of v5rgi.n forest were also included. 

The range of forest types and vegetational dominants encountered in this region were very 

similar to those on Mount mrasfield with the 

notable absence of extensive stands of balsam 

fir and stunted coniferous vegetation. Elevation at this study site ranged from 450 - 550mCommunity Patterns 

Species Composition 

We have previously described the commity 

structure pattems on four mountains in New York 

and Vemont (Able and Noon, 1974). There were 

great similarities amng the four gradients; 

for this comparison we have used data only from 

Msunt Mansfield, Vermnt, the gradient we 

studied most extensively. 

The Mt. Mm~f geld and Smky Mt. elevational 

gradients encompassed a similar (structural) 

range of forest habitats and each gradient had 

the same nunber of species, 41. There were, 

however, considerable differences in the species 

cornposit ion on the two transects ; they overlapped in slightly Less than two-thirds sf their 

speciw. Sixteenqecies (39 percent of the 

total) on the Smoky ME4 gradienc were not present on Mt. Masfield (Corn. Flicker, 

auratus; Pileate 

Acad ian Fly catcher, 
anus; Blue- gray Gnat catcher , caerulea; R1lot~-throated Vi 

frons; Worm-eatbg garbler, Helmitheros Emivorus; GeruLetur Warb Eer, Dendroica eerulea; 

Yellow-thraated Warbler, t). dombica; Chestnutsided Warbler, 2. Louisiana 

Waterthrush, Seiu Kent ticky 

Warb Zer, oded Mafiler, 

WiSsonia citrha; Cardinal, Richmndena cardbalis) . Fourteen species (34 percent) absent on the Swky. Mt. gradtent were found on 

He. &nsf ield (Least Flycatcher, g. niniaus 

bven, Corms B; mite-breast4 Nuthatch, 

Sitta carolinensis; Hemit Thrush, g. 9 

Swahson % Tnrush, Catbarus ustulatus; 

cheeked Thrush, 2. ninimus ; Cedar Wa-mizllg, 

cedrorura; Nashville Uaa"b ler , '%9ll~-rumped Warbler, 

mrbler, I). striata; 

Mourning Marblor, 2. ; Comn 

Yellowthroat , trichas; Purple 

Finch, ; mite-throated 

Sparraw, Zonotrichia albicollls) . Many of 

these differences between tha two Localities 

involved abundant and broadly distributed 

species. &%en one consfders a spectrum of 

heibitats such as occurs on these elevatioml 

gradients, the southern avifma caslnot be 

considered an included subset of the northern 

as RabenoLd (1976) found when only spruce-fir 

fareats in the two areas were exasrtined. 

Figure 1 compares partems sf species 

diversity on the two gradients. Species 

richness and tvo indices of diversity are 

plotted. In both regions, the three masures 

of diversity tend to be highly correlated, 

but there are obvious differences in pattern. 

On Mt. %nsfield both diversity indices closely 

parallel the trend in species richess and 

all generally declfrrred with elevation. In 

the Smoky Mountains, dpecies richness fluctuated greatly but still showed a downward 

trend with elevation. Nl and N2 also showed 

considerable variation over the length of the 

gradient, but if a trend similar to that of 

species richness is present it is very slight. 

'1Che relative flatness of the diversity curves 

is in marked contrast go those for Eft * Ehnsf ield. 

Because the species richness of the Smoky 

Mt. commities is essentially the saw as on 

Mt. Mmsfield the marked differences in diversity must be due to differences 2n equitability. 

This can be seen graphically in Fig. 2 which 

eonrpares damhanee-diversity curves for the two 

gradients. The Smoky Mt. cornmities are characterized by much higher dominance and a greater 

increase in dominance over the span of habitats 

relative to Mt. Mansf ield. Figure 3 presents 

an analysis of dodnance comparing the Smoky 

Mt. commities with those on Mt. Mansfield and 

nearby Camel's Bump Mt. by Wiens ' (1975) method. 

For a cornunity with a given number of species, 

the samples from the Smoky Mts. had significantly 

higher dominance (pc.025; Plana-Whitney, onetailed) than the two northem mountains. 

The overall difference in dominance in the 

two regions appears to be due to higher relative 

abundances of the commonest one or two species 

in the Smoky Mt . c ities rather than to a 

difference in numbers of rare species. This 

can be seen in Table I which ranks the relative 

abunbnces of the four cornonest species at 

selected elevations on the two mountains. At 

all but one of these sampling stations, the dominant Smoky Mt . species had much higher pi's 

than their northern counterparts. Hean proportional abundances of all the species comprising 

GREAT SMOKY MIS. -I2 

Figure 1,--Plots of speeles rechness (No) and diversity with elevation on Kt6 Plansfield, Vermnt 

(A) and Great Smoky Mountains (B) . N1 = EXP(H') ; N2 = l/gR 2. 
Species sequence 

Figure 2. --Dominance-diversity curves for selected elevation on Mount Mansf ield, Vermont (A) and 

Great Smrky Mountains (B). Each species is represented by its proportional abundance in the 

sample (pi) on tha ordinate, and its rank in the sequence of species from the most to the least 

abundant on the abcissa. Indices of dominance, d = Ni,,/N, are given for each curve. 

5 18 15 2a 25 

Number of species 

Figure 3.--Comparison of degree of dominance 

for given nurnbers of species in cornunities 

on klount Mansfield and Camel" Hump Mountain, Ve mon t, 

a census was always higher and generally more 

variable on Mt . Mans field than in the Smkies 

The major differences in species composltlon between the two regions precluded a 

paired comparison, but the abundmces of the 

less comon species were generally similar. 

The great difference in dominance was largely 

due to the much greater nos. st the most abundant 

species# As a result of this, nearly all elevations in the Smoky Mts. supported a significantly larger nuaibes of hdividuals than comparable sites on my of the northeastern gradients (wan no. indivs /hre, a21 stations, 

Smoky Mts* = 170.79 S*D. = 28.3; Mt. ensfield 

X = 100DO; SOD. = 33*5; miteface Mt. % = 148.4; 

S.D* a 55*7)* 

On bath northern and southern elevational 

gradients a few species with very generalized 

habitat preferences were found over nearly the 

entire transects (Table 21, In the Northeast, 

the Dark-eyed Junco ( and Mhitethroated Sparrow ranked among the top five 

species on all four mmltains (Able and Noon, 

19761. Three of the six broatdest species on 

Nta Mansfield were among the five bradest in 

the Smky Mts. In addition, the Black-throated 

Green Warbler (Dendroica virens) ranked fifth 

on h%iteface Mt in the Adirondach sf New York. 

Thus there appears to be considerable similarity 

in the amplitude patterns of the hahitar generalists in the two regions. 
Table 1.--Ranking and proportional abundances sf the four most abundant species at selected elevations on Xcunt Pfnslie3.9, Vermont, the Great Szrioky 3iountains. Mean F~ values for all 

species at each elevation are alsz given. 

Species pi Species Pi S 2ec ii;s pi Species Pi 

Mount ?fans field 

El. 610m -71_ 

8 LIZ 

RedmeYed Vireo 1 5 7: '?eb-c:v& **- L - 3- a L:;G elat-kn30.1 L 'a:ap.klep. .2353 k%,-thr. Sparrow 3333 

Amer. Redstart .(I44 ? Jdrk-e"-ez bJ LL~G 3 +lt, \qh- -~l~r= Sparcsv 179 5 b Lick~olj \<arbler -2941 

Oven b it3 *G,?G -ir~r= :iarJl~l 4.4i t #Aii~G?r LJrecA .I029 hasitvllir Marbier .I078 77:. 

Food Thrusl: .(~714 der;f,lcYr&rus? -2527 ~wai;bson's bhrusrs . ~629 "iel. --ruri.gr* Warbler: .07134 f>4t,lAJ e CG2 7 , jl69 ,1256 

S.D. - G3flb s 13343 a 06 6- .&22..L 

Great Smoky ~Jlo&'icalns 

El... 610nt 9 76~ 

9 Red-cyed Vireo ~~fi6 Red-eyed Y-rec ,2393 Dark-eyed Junco -2613 ark-eyed Junco * 2896 

Gvenls 5 h;.d -1832 8 L- &fir. blbe '!=re . 193 Veer?; -0887 Cold. -era Kinglet . I639 

BI. -rhr. Green \dare 1353 3L. 6:tr. Green bar. .07?6 ~1~-cap.Chlekadee,O38: Bi.-thr.Green Ware 01585 

&mere Redstarr .I068 Ov;r.=rbircZ. .ci7iiX. BLac~burcian War. ,0887 SoLltary Vireo * 1148 

pi -0 53.: a 5490 * 062.5 .a716 

S .D. e 4~558 - 2599 *0548 .0837 

Table 2.--glevacior1;it alr2li~tade rankings or' che f4 Lie species on each mountain with the broadest 

dis tcibutions on the grda ients. 

hplLtude -t 2kn3field 

Rank 

Species Arap L it ude r Eioaal Species 

-..-----,.-.-2d-- --- jtuce 

Z Dark-eyed Jmce 660 

2 I.liinteg drer-j 661: 

3 ~b*-*.- Chickadee 6LO 

4 \4-t.---thr. Sparrow 495 

5 Hairy Koodpea~er 44; 

6 Bae r . RoS i ar 49 5 

* 943 Wairy tdaodpecker 1372 *99& 

* 963 Araer. Robin 137 -90 ; 

. 371 El*--chr. Green Xar- 1372 .99- 

7127 So ii-racy Vireo 1098 '796 

, 7'47 Cark-eyed Junco 1098 .796 

1~ 7 
In general, species in the Great Smoky 

Mts. occupied a larger proportion of the elevational gradient. Nowever, in both areas a 

few species whose distributions appeared not 

to be artificially truncated by the ends of 

the gradient were nonetheless characterized by very narrow ranges. In the Northeast, the Golden-crowned Kinglet ( 

satrapa) and Canada Sdarbler (Wilsonig canadensis) were found in the middle elevations, 

but had narrow amplitudes of between LOO150m (about 18 percent of elevational range). 

In the Smky Mts. , the Kinglet was agein 

antong the narrowest species with an amplitude of about 275m (about 20 percent of 

elevational rage) and Brmn Creeper (Certhia familiaris) was simila r. 

In both regions, the mean amplitude of 

the species at each sampling station increased with elevation and decreased with 

species richness (Fig. 4). These relationships say that the high elevation faunas of 

these mountains are made up largely of 

habitat generalists which dominate the depauperate communities at the tops of the 

mountains. The high elevation community is 

basically a subset of lower elevation avifaunas and at high elevations the most abundant species attained both greater dominance 

and absolute abundances than lower elevation dominants. bong all species on the 

gradients there is a positive correlation 

between amplitude and abundance (Able and 

Noon, unpubl. data). Of the 10 most numerous species, a11 but two also ranked amcag the 

10 species with the largest amplitudes on the 

gradient. 

Cornunite Structure 

Patterns of species turnover on environmental gradients can give insight into mechanisms producing comunity structure. We 

have examined the similarity of species cornposition and relative abundance at sampling 

stations along the gradients using a dissimilarity index (~acArthur, 1972, p. 189) : 

where pi and qi are the proportions of species 

- i in samples 2 and q, and 15 M 2.2. Figure 5 

compares Mt* Mansfield and the Smky Mts by 

plotting the similarity between the lowest 

stations and each successiveLy higher station. 

In general, the functions should increase as 

the distance between stations being compared 

increases. An increase in the slope of the 

line indicates a greater change in comuni ty 

composition between two stations. 

On the four mountains studied in the 

Northeast, increases in diss%dlarity (i. e., 

increases in H) were associated with ecotones. 

Mt. Mansfield, the steepest of the four, was 

slightly atypical in that the two ecotones 

appeared to have been treated as a single dFscontinuity, at least as far as our analysis 

was able to discriminate. The pattern on the 

Smoky ZLft. el.evationaf gradient was very similars 

with a very large and abrupt faunal change between the stations ar 1057rn and i158ms The 

data from both areas suggest: a major -influence 

of habitat discontinuities in deterdning the 

distributional Units of species on these gradients. mereas there are obvious and large 

changes in species cornpasition and relative 

abundances on the Smoky Mt transect, the magnitude sf the effect is not as great at the 

species level as in the Northeast (Table 3). 

Only about one-third of the species 'distributional lin&ts coincided with ecotones in the 

Smoky Mts. coolpared with slightly more than 

half of such limits in the Northeast* In fbct, 

the proportion of species limits associated 

with ecotones in the Smokies does not differ 

from that found by Terborgh (1971) in Peru 

(with data norntalized for number of sampling 

stations associated with ecotones). However, 

ecotones still exerted a large effect in the 

Smokies through changes in relative abundances. 

En our earlier paper (1976) we failed to 

find any evidence of overt competitive exclusion 

in the distribution patterns of the species. 

Further detailed studies of the five thrushes 

on these gradimts has also failed to reveal 

any interference competition (e go, interspecific territorjality) (Noon, 19 77). In 

the Great Smoky Mts*, cases suggestive of spatial 

competitive exclusion were even rarer. The Vood 

) and Veery (Catharus 

(Vireo o livaceus) 

and Solitary Vireos (x. solitarfus), as well as 

a host of parulid species, overlapped broadly 

on the gradient. Among congeners, only the 

Carolina ( and Black-capped 

Chickadees were eont inguously 

allopatric, although neither reached near niaxianal 

abundance adjacent to the contact zone. Thus 

with respect to evidence of interspecific cornpetieion in the form of intra-habitat spatial 

exclusion, the pattern in the Smkies appeared 

to be virtually identical to that in the Northeast . 

The species comprising the breeding avifaunas of both regions are gredodnantly migratory, inhabiting these forests only during the 

relatively short breeding season* There are, 

however, noticeable differences between the two 

areas with respect to the proportions of species 

and individuals that are long-distance migrants. 

About three-fourths of the species included in 

our censuses of New England momtains are migrants that leave the region in winter. In the 

Smoky Xts. only 62 percent sf the species mke 

migrations more extensive than short-distance 

alt%tudinal movements- A much mare striking 
Ln Elevation 

Ln Elevation 

2000 4 8 12 16 20 24 2 

Number of species 

300b ' ' A '1;' I; ';Oii4'28 

Number of species 

Figure 4.--Regressions of mean species amplitude at given sampling stations on elevation 

and the species richness at the station. A and 8, northeastern mountains: X Mount 

Mansf ield; e Camel's Hump Mountain; 0 Whiteface Mountain, New York; A Nippletop Mountain, 

New York. C and D, Great Smoky Mountains. 

difference can be seen if one compares 

proportions of individuals that belong 

to essentially resident species. On Mt. 

Mansfield, this figure varies between 

about 12 percent (lowest elevation 

sampled) and 2 percent (highest station) 

(mean = 7.2 percent) . In contrast, the 

proportion of individuals belonging to 

residenr species ranged fron~ about 4 

percent (8841x1 station) to 66 percent 

(highest station) (mean = 29.7 percent) and generally increased with 

elevation. 

Ttre difference between the two 

regions was due alnmst entirely to the 

high importance of Dark-eyed Junco, Blackcapped Chickadee, Golden-crowned Kinglet 

and Red-breasted Nuthatch above the first 

ecotone at around 11601~- In general, resident species did not reach higher abundance 

nor did they have larger amplitude than migrants (some examples are shown in Table l). 

Population Patterns 

Northeastern Montane 

Distributional Analyses. -- A particularly 

interesting pattern of our northeastern montane 

censuses was the diversity of thrush species 

(Hylocichla and Catharus) occupying these 
Elevation (rn) 

Figure 5.--Plots of the index of faunal dissimilarity (M) between the lowest elevation station 

and each succeeding higher one on Mount Manrsfield (A) and between the lowest two stations 

combined and each succeeding higher one in the Great Smky i4ocintains (B). 

Table 3.--Elevation limits of species distributions in relation to ecotones on five mountains. 

Mountain No. of Limits No. at Proportion Proportion sf limitsf 

excluding termirri ecotones at ecotones ecotone station 

Whiteface (NY) 3 5 

Nippletop (NU) 34 

Plans f ield (VT) 39 

 ame el's Wump (VT) 39 

Gr. Smoky (Tenn.) 40 

gradients. When the relative abundances of 

the four most abundant species at each sampling station were calculated, one or more 

thrush species ranked in the top four at the 

majority of sampling sites. Figure 6 illusstrates the distributional patterns of the 

thrush species on Mount Mcmsfield. Plotted 

are abundances, normalized and expressed as 

the number of individuals of species _i censused per hour. The patterns illustrated 

here were qualitatively similar for all four 

northeastern elevational gradients. 

From the figure it is apparent that 

the Wood thrush and Veery had very similar 

distributions being mst abundant at low 

elevations and reaching their upper limit 

together at the lower ecotone. The Hermit 

thrush bred at low elevations but showed 

variable abundance, extending beyond the 

lower ecotone into mid-elevations. At 

higher elevations the swainson's arid Graycheeked thrushes inhabited mutually exMT, MANSFIELD I THRUSHES 

Figure 6.--The abundances of the thrush species 

on the Vermont elevational gradient, species 

of thrushes are denoted as: (A) Wood thrush; 

(B) Veery; (C) Hermit thrush; (D) ~wains~n's 

thrush; (E) ray-cheeked thrush. 
clusive ranges. The swainson's thrush overlapped extensively with the hemit thrush at 

the lower end of its distribution, but had 

mimimum overlap with the gray-cheeked at its 

upper extent. The truncated distributions 

of these two species at their zone of contact 

suggests interference competition except 

that this point coincided with the upper elevationaf ecotone* 

Habitat Analyses. --During the breeding seasons of 1975 and 1976, habitat quantifications were done for the five thrush 

species breeding on munt ??,ansEield. Fifty 

habitat quantifications were done for each 

species with each qumtification consisting 

of measureaents on 58 structural habitat 

variables (details given in Noon, 1917). 

Each species was represented in the data 

matrix by 50, 58-element observation vectors. 

Univariate analyses (one-way analysis of 

variance) of the structural habitat variables revealed patterns of intrahabitat 

separation for overlapping species and 

interhabitat separation for species with disj unct elevational distributions. Each of 

the variables nteasured was regarded as a 

continuous gradient quantifying some aspect 

of the breeding territories selected by 

these species. Over lap was extensive along 

most of these gradients, but all species 

showed patterns of separation along a unique 

complex of variables- Simultaneous differences along a multitude of gradients resulted in a significant increase in separation. However, many of the variables 

measured were highly correlated, and the 

danger of achieving a distorted picture 

of the nature and extent of group differences increases as the correlations amng 

the variables increases * 

An alternative way to describe group 

differences is to use discriminant function 

analysis which constructs a linear combination of the set of variables that will maximally discriminate the groups. The linear 

combination is a new, transformed variable 

composed of the original variables each 

weighted according to its power to distinguish the groups. Species ' positions are 

then examined in term of their ranking 

along this linear conbination. By this process, species "ositions on several independently measured univariate gradients 

(which may be highly redundant) are reduced 

to a single position along a multidimensional gradient of habitat structure. This 

reductfon in dimensionality simplifies elucidat ion of speciesi differences and facilitates quantitative comparisons amng the 

species in terms of a few highly eignificant 

variables- For an indepth discussion of the 

applications ~f discriminant analysis to ecological problem see Green (19 71, 19 74). 

The use of discriminant function analysis 

as a powerful tool for forest mmagers was 

proposed at a previous meeting of this group by 

Shugart et ale (1975). The speclf ic advantage 

of this type analysis is that it reduces complex multivariate data to a manageable and significant subset of the original data. In 

addit ion, it goes beyond adiguous univariate 

correlational studies (shch as the relationship 

between foliage height diversity and bird species 

diversity) to identify features of 

habitat structure strongly correlated with a 

species ' presence. 

The results of multiple step-wise discriainant analysis of the thrush guild are presented 

in Table 4. The number of variables needed to 

significantly distinguish the structural habitats of these species has been reduced from over 

50 to nine. A test of the discriminatory power 

of the subset of nine variables prior to the 

removal of any discriminant functions indicated 

that they contained a highly significant amount 

of discriminatory power (Wilkk lambda = 000379; 

associated chi-square - 792; p<.001) . In addition, 96 percent of the variability in the predictor variables can be explained by group differences (w2 multi = 96). 

The proportion of the discriminatory power 

contained in the subset of predictor variables 

attributable to the tth discriminant function 

is given by the ratio: pi X i / (Al + h2 +. . .A,). 

where X = the eigenvalue of the 5th discriminant 

function. Pi is an index of how the total discriminatory power of the predictor variables 

is apportioned to each discriminant function. 

Thus, 85 percent of the discriminatory power of 

the predictor variables is accounted for by the 

first discriminant function, 7.9 percent by the 

second, and so on. The discussion which follows 

confines itself to an analysis of the first two 

functions which collectively account for over 

90 percent of the discriminating power contained 

in the analysis* 

Additional information essential for an 

understanding of the analysis are the st andardized discrinrinant function coefficients 

given opposite each variable in the table. The 

absolute value of each coefficient is proportional to the relative contribution of its 

associated variable to group separation along 

that discrid-t axis* The sign merely indicates whether the variable is =king a positive 

or negative contribution. These coefficients 

may be used to interpret the functions by ident ifying the dominant charaeterist ics by which 

separation occur. 

The positions of the species1 mean habitat 

vectors in discriminant two-space, as well as 

the 95 percent confidence limits around these 

in Pig. 7. The relative 
Table 4.--Sumary of Multiple Stepwise Discriminant Analysis 

Discriminant Function 

Characteristic: 

E igenvalue 7.94 0. 735 0 . 395 0.220 

ReLative percentage of 

eigenvalue associated 

with the function 

Cumdative percentage 

of eigenvalue across 

all discriminant 

f unct ions 

Chi-square statistic 

for testing significance of discriminant 

function 

Significance 

(degrees of freedom) 

Standardized Discriminant 

Function Coefficients 

CPCR 

GDCR 

RDBA 

USCF 

ADDC 

TALL 

SBDY 

NOTS 

AVDI 

ADDC - absolute density of deciduous trees NOTS - number of tree species 

AVDI - average diameter of trees RDBA - relative basal area of deciduous trees 

CPCR - percent canopy cover SBDY - shrub density 

GDCR - percent ground cover TALL - canopy height 

USCF - percent of understory coniferous 

positions of the group centroidsreflect individual responses to structural niche variables 

as well as the difference among the species in 

their response to habitat gradients. The magnitude of the distances separating species in 

this plane reflects the degree to which their 

habitat selection patterns differ. The further 

apart any two species ' mean observation vectors are in this space, the less similar are 

their structural niches. 

To understand the manner in which signif icant segregation is achieved and the contribution of each variable to separation, it is 

instructive to look at each discriminant axis 

independently (Fig. 8) . 

Canopy cover (CPCR) , canopy height (TALL), 

and percent understory coniferous (USCF) were 

the dominant variables describing DF-I. The 

function is in effect a gradient reflecting 

canopy features and the deciduous to coniferous 

continuum which parallels the gradient of 

elevation. The discr hinant function represents a macrohabitat description of the change 

in forest structure and composition as one proceeds from low to high elevations. The extremes of this gradient are occupied by habitats selected by the Wood thrush and Graycheeked thrush. The habitats selected by the 

Wood thrush are characterized by high canopy 

cover and height and low percentage of conif erous understory, whereas the G ray-cheeked 
thrush selects stunted spruce-f ir forests where 

the relative mgnitudes of these variables are 

reversed. Species positions along this discriminant axis are consistent, and in the same sequential order as, their distributional pattern 

along the elevational gradient. For example, 

the Gray-cheeked thrush is widely separated 

from all other species which in turn are clustered along the positive portion of the axis. 

The Wood thrush and Veery have almost coincident centroids on this axis reflecting their 

DF-II complete overlap along the elevational g- rad ien t . Extensive overlap occurs because variables reflecting interhabitat differences are unable to 

discriminate these two species. 

Canopy cover and height were again the most 

dominant variables characterizing DF-11, but in 

addition, shrub density (SBDY) and the absolute 

density of deciduous trees (ADDC) contributed 

substantially to group separation along this 

axis. The pattern of covariance among these 

variables describes a gradient of habitats from 

those characterized by relatively high canopy 

DF-t cover and height, dominated by deciduous trees, 

to habitats of dense shrubs with an open and 

of ten low canopy. species ' posit ions along 

this gradient are again interpretable in terms 

of the continuum. of forest types which characterize the species' elevational distributions, 

Figure 7.--95 percent confidence ellip- but, in addition, variables reflecting intrases about the means on DF-1 and DF-11 habitat separation are important for group 

for the five northeast thrush species. discriminat ion. For example, the relative poSpecies of thrushes are denoted as : sitions of the Wood thrush and Rery centroids 

(H.m.) Wood thrush; (C. f) Veery; are significantly separated along this axis 

(C . g) Hermit thrush; (C. u. ) Swain- primarily because of the contribution of shrub 

son's thrush; (c. mb ) Gray-cheeked density The most extensive separation occured 

thrush. between the Swainson's and Hermit thrushes 

F.C. m4 1-C. u4 

f-c. w 4 rC.f. 

DF- I 

-2.0 . 0 

L ow Canopy Cover High 

Low Canopy Height High 

% Understory Coniferous Low High 

t-'--C.f.+ 

.O -2 

High Canopy Cover 

High Canopy Heig hi Low 

High Shrub Density Low 

Low Abs. Density of Decld. Trees High 

High Ground Cover L o v 

Figure 8.--Thrush species positions on each independent discriminant axis* Species deno 

8s in Fig. 7. 

ted 
primarily because of the influence of shrub 

density coupled with gromd cover: both 

microhabitat variables reflecting the mosaic 

structure of the habitat in the area in which 

these species overlap. 

The most direct va3r to test the discriminating power of the variables selected by 

the malysis is to deternine their effectiveness at accurately assigning the observations 

to the correct species' group. If a large 

nuder of misclassifications occur, then the 

variables selected are poor discriminators. 

In practice, the actual and predicted group 

membership results are compared for those 

observations actually used to derive the 

functions. The power of the discriminating 

variab Les is empirically detemined by the 

proportion of correct classifications The 

results for the five northeastern thrush 

rized in the classification 

matrix given in Table 5. 

By employing a subset of nine of the 

original 50 structural variabies over 77 

percent of the 250 individual quantifications 

have been assiped to the correct species' 

group. The accuracy of assipment varies 

among the species and this in turn supplies 

information on the degree of ecological sirni1a-iry of the various species pairs. The 

number of groups to which a species is misclassified and the extent: of this aisclassifieatioa is a crude index of habitat niche 

breadth for the species. Par example, of 

the five species considered here the Hermit 

thrush occupies the widest range of habitat 

types and thus wodd have the largest niche 

breadth. 

Table 5. --Classification Matrix 

From the perspective of habitat assessment 

the results presented here indicate that by 

quantifying just nine structural habitat variables, the forest wnager could predict with 

77 percent accuracy what thrush species occupies 

a particular patch of forest. Of course this 

statement ntay need to be qualified because this 

pattern of habitat selection may be unique to 

northeast montane forests or, perhaps, solely 

to Mount &nsfield- In order to develop a 

workable management scheme to increase the 

breeding status of the Veery, for example, it 

is necessary to test the generality of the 

habitat selection model developed from the 

Mount Plansfield study area. For avian species, 

an assessment of their habitat associations in 

vegatationally similar comunities, adjacent 

and geographically distinct , would constitute 

a powerful test of their generality of habitat 

selection. To this end we performed identical 

habitat analyses of thrush species in the Smoky 

&fountains and in non-montane areas in northern 

New York State- In essence, we will rest the 

accuracy with which the classification hctions 

(based on the nine discriminating variables) 

derfved from the Vermont study assign thrush 

individuals breeding in other locales to their 

correct species group. The proportion of correct classifications is an empirical index of 

the generality of their habitat selection. 

Southern ltSontaae 

Distributional Analyses. --During May 19 77 

an extensive elevational transect on the Tennessee side of the Great Smoky Mountains National Park was censused. As discussed earlier, 

the census results included info 

Predicted Group 

Swainson's Gray-cheeked 

- N -- Wood thrush Veery -- Hedt thrush thrush thrush 

ox (is) 

Percent of observations correctly classified: 77.6% 
species composition and distributional patterns of these montane avian comunitiesAt all sampling stations thrush species were 

a slgmificm~ component of the species corn 

pleaent- The Wmd rhrush generally had 

lower relative absolute abmdance than on 

northeastern gradients while the Veery had 

comparable abundance (Fig* 9) Some of the 

decrease in the idood thrush density may be 

attriSutable to time of sapling. The 

early spring of 1975 was unusually warn and 

the species way have been sufficiently 

advanced into its breeding cycle as to be 

vocalizir.ig Less frequently. 

THRUSHES 

Figure !?.--The abundances of the thrush 

species on the Smoky Nountain elevatisnal gradient. Species denoted as 

in Fig. 7. 

Note from Fig, 9 that the Wood thrush 

distribution pattern in the Southeast was 

comparable to the northeastern pattern. Ir 

occupied the lower altitudes along the 

gradient and its upper elevational terminus cohcided with the lower ecotone as 

on Mount Hans field. However, the distriburrion pattern of the Veery was markedly 

different. It did not appear on the gradient until mid-elevations (but below the 

first ecotone) and extwded all the way to 

the upper terminus sf the gradient. Unlike 

their northeastern diat ribut ions, the Wood 

thrush and Veergr tended to inhabit mutually 

exclusive ranges along southeastern mountains. In addition, both species showed 

evidence of mplitude expansfon. The Wood 

thrush and Veery occupied 37 percent OF the 

northeastern gradient but occupied 56 percent and 68 percent respectively of the southeastern trmsect. 

Habitat release indicates shifts in a 

species' structural habitat niche to include 

areas of niche space occupied by putative competitors in sympatry (e. g., Crowell, 1961, 1962; 

Diamnd, 1970; Peaton, 1974; Terborg and Weske, 

1975; and others). The amplitude expmsion ad 

elevation distributional pat terns of the two 

southeastern thrush populations, particularly 

the veery's shift to high elevations, implies 

that habitat release has occurred fur these 

species. However, to convincingly argue that 

release has occurred, it is necessary to establish that niche shifts have occurred along 

critical niche dimensions. Optimally, these 

will be dinensions quantifying proximate cues 

used to assess habitat suitability. Operationally, they are usually dimensions derived froa 

multivariate statistical analyses and thus potentially both highly correlated with and powerful predictors of a species' presence. 

Habitat Analyses.-- To rigorously test the 

specificity of the species' habitat selection, 

and thus the generality of our model, each of 

the southeastern observation vectors were individually classified by their highest probability of species membership. By classification 

is meant the process of identifying the likely 

group membership of an observation vector according to its values on the discriminating variables. 

Classification is achieved through the use of 

linear classification equations derived during 

discriminant analysis from the pooled withingroups covariance matrix and the centroids for 

the discriminating variables (Klecka, 19 75) . A separate equation is derived for each group 

in the analysis. The classification score for 

each observation for each group is determined 

by multiplying the raw variable values by their 

associated coefficients, and adding these together along with the group constant. The observation is then assigned to the species group 

with the largest classification score. 

The results of the classification of the 

southeastern Wood thrush and Veery populations, 

according to the functions derived from the 

northeastern guild, are presented in Table 6. 

Only 45 percent of the Smoky Mountain Wood thrush 

hdividuals were classified as selecting 

habitats structurally comparable to their northeastern counterparts. Contrast this value with 

the 78 percent correct classification for northeastern Wood thrushes* Smoky Hountain Wood 

thrush mast frequently select habitats Like 

those selected by northeastern montane veeries. 

Fifty-one percent of the southeastern Veery 

observation vectors have structural niche configurations consistent with their northeastern 

conspecifics. Thirty-two percent sf the population selected habitats structurally comparable 

to those selected by the Swainson's thrush, 

whereas only four percent of the population 

selected habitats of this type on bunt Xansfield* This represents a substantial expansion 
Table 6.--Classification of Smoky Plountain observation vectors by Xouat P"iansfield elais~fisariorr 

functions. 

Predicted Group Mesnb ershlp 

Act d bwainsun \ Gray-cheeked 

- Crox - N -- Mood thrush Veery -- Hermit thursh -- tl-trush -- t ilu Llsh - 

W.T. (s) 47 45% (21) 49% (23) 4% (2) 2;: (11 ox jo) 

into the habitat types which are not utilized 

in the presence of the swainson's thrush. 

The extensive habitat release observed 

for both these species suggests a strong role 

for interspecific competition in shaping the 

specific habitat selection patterns detected 

for the northeastern montane populations (see 

Noon, 1977). The most pertinent issue relative to the topic of this paper, however, is 

the lack of consistency in structural habitat selection between these geographically 

distinct montane thrush populations. 

Changes in a species composition as well as 

structural habitat may result in significant shifts in habitat utilization. The 

model of habitat select ion generated from 

the study of northeastern montane thrush 

populations cannot be generalized to vegetationally similar southeastern montane fores ts* Development of habitat management 

scheme for forest species may become greatly 

complicated because of niche shifts which 

accompany changes in a species' biotic envi ronmen t . 

The r ,he shifts observed in southeastern 

thrush populations may have been predicted 

to some extent because of potential genetic 

and/or phenotypic dif f erences in populations 

occupying opposite extremes of the species 

distributions. In addition, there may be 

subtle structural changes in forest physiognomy which precludes the species selecting 

identical structural habitats at these two 

geographically distinct areas. However, 

foliage height diversity profiles for sprucefir forest in northern Maine and the Smoky 

Mountains are almost identical (Rabenold, 

19 76) , indicating the structural differences 

may be slight. 

To more rigorously test the generality 

of the habitat selection model established 

from &unt Mansfield, we studied thrush populations at a comparable latitude but occupying 

nan-mon tane forests* This comparison may 

control for significant genetic or phenotypic population differences as well as subtle 

structural dif lerences in 7~eget;atian s rructur-e. 

This study area was occupied by at1 of the northeastern montane thrush spec.he8 except the Graycheeked thrush. The ntetl-ttlods of locati~lg -Indi-, 

viduals and quantifying tiieir brredlsg t-er:"itories were identical to those previously employed. 

The classification results for the 54 hab-itat quantifications are presented in Table 7. 

All thrush species, except the Sw;ii.nscin 's thrush, 

are predoninantly ciasslf ied into the" LI" cctrrecc 

species group a However, the accur;zc:p (311 class1 - f ication has dropped subs tan ti all:^ ftar nrssr 

species, particularly for the Swai~zf;on 's thrust 

which is strongly misclassif ied as dood thrush. 

The pattern of misclassification for che Swainson's thrush is particularly surprising because 

this species and the Wood tllcush :*hn~ vir";rla1lv 

no spatial overlap on any af the xlartheasterri 

elevational gradients (Able and Moon, 19 76) . The 

results imply that the habitat select ion made1 

cannot be readily applied to adj ace nt non-a~ntane 

axes I 

We propose two tenatlve hypoei?enev cc cxplain the lack of generality in Labxtar selection for these thrush populations. Tllc Eirst 

of these concerns the distribution of vegetational patches with particular structural aetributes. Habitat patches with the appropriate 

structural configuration for a speetfie chrrt.-:la 

species appear to be smaller ire spatra.1 rxte~~r 

and more randomly distributed ill the- Cr-anberry 

Lake region than on adjacenh, mo~mtaiiis. T11is 

difference between montane arid ncrn-117r~~ntanc att-as 

is most likely the result ol st.rXrter btegerdtlonal zonation on mountains; a coilsequtinze of 

rapid change in abiotic influences dhi ch control 

plant species distributions. IF rhe species respond to this change in grain by increasing territory size (in order to keep che asrwunt: of 

suitable structurraZ habitat- si;l&ri,vef-, cionstarit) 

then their habitat selection will not appear to 

be as specific as on rnomtai~rs~ Two types of 

data are needed to test this hypothesi3 : first, 

it will be necessary tc clocun~ent r-tiae hdbitat 

types are mere patchily d.is&rlbuted ic sh5s 

locale than on notintains, and second, eo es- 
Table 7,--Classificatian of Cranberry Lake obsemation vectors by Mountain mnsfield classification 

functions. 

Predicted Group Me&ership 

Act uaf 

- N -- \$sod thrush 

Swainson 's 

-- Hermit thrush thrush 

tablish a relative increase in territory size 

from montane to non-montane areas. Data of 

this sore will be collected over the next few 

breeding seasons. 

The second hypothesis concerns historical factors. The geographical range of the 

mod thrush has dramtically expanded over a 

short period of time. Only since 1890 has 

this species become a regular component of 

the breeding avifmna in the northeastern 

United States and Canada (Bent, 3949) . Evidence supplied by Mgrse (1971), from an area 

in northem Maine recently invaded by the 

Wood thrush, indicated that the thrushes my 

be interspecifically territorial. In those 

aggressive encounters reported, the Wood 

thrush was behiavioralLy dodnanf: and my 

have preempted territories previously occupied by other thrush species. However, in 

areas studied by Dilger (1356) and Noon (1977), 

where the Mood thrush was not a recent invader, there was no evidence of interspecific 

territoriality. In the Crmberw Lake region 

the Rood thrush my be a recent addition to the 

breeding avifama (Adam, 1923) and its abundance is still substantially lower than any 

of the other thrushes. Because covert conpetitive interactions contribute strongly to 

these species ' patterns of specific habitat 

selection (Noon, 1977), the Cranberry Lake 

region may not have reached a competitive 

equilib rim. Nsn-equilibrium patterns of resource utilization may be sufficient ts explain the observed degree of habitat misclassification (though not the specific 

pattern of misclassifieat ion) . 

Ts suraarize, tesrs in other locales sf 

the habitat selection mdel developed from 

an extensive multivariate study of the breeding habitats of the northeastern montane 

thrush guild have indicated a lack sf generality. In southeast mountains where two of the 

f ive guild merabers remain, habitat niche shifts 

have occurred as the result of changes in their 

compet it ive environment (Noon, 19 7 7) . In nonmontane, but adjacent, areas in the northeast 

shifts in habitat utilization for some species 

are hypothesized to be the result of vegetational and historical factors. The implications are, at Least for some forest birds, that 

habitat management schenes will have to be 

tailored to local conditions. 

DISCUSS LON 

Habitat sele ction in passerine birds appears to be influenced by the physical strueture of the vegetation without particular regard to the plant species present- In a variety 

of multivariate studies of avian habitats differences in a few structural variables were suff icient to significantly discriminate even very 

diverse comunit ies (Whitmore, 19 77) . This consistency argues for some overriding patterns 

of cornunity organization. Comparisons of community-level patterns of organization for northeastern and southeas tern elevat isnal gradf ents 

have been presented. In general, the patterns 

of organization tor these communities are quite 

similar, but with noteablie exceptions. The similarity of organization may most likely be a 

consequence of the migratory nature of the 

majority of breeders on these gradients. 

Perhaps the most striking feature that 

emerged from the comparison of cornunity structure on elevational gradients In the northern 

and southern Appalachian Mountains is their 

strong similarity. In terns of species richness, 

whether viewed over the entire gradient or an a 

station by starion basis, the two gradients were 

virtually identical although there were many differenced in species composition. Rabenold (19 76) 

compared the breeding birds of spruce-fir forests 

in Maine and North Carolina and concluded that 

the southern fauna was a depauperate subset of 

the northern. We did not find such a striking 
difference and ~abenold's species list suggests that the Maine site may have contained 

greater horizontal heterogeneity. Tkis 

coupled with the presence of spruce budtaorm 

specialists can account for at feast part 

of the difference. Based on our data, the 

mntwe avifauna of the southeast does not 

follow the general trend of lower species 

richness southward discussed by Tramer (19 7 4) a 

The cmmunities were also quite similar 

with respect to the absence of obvious competitive exclusion patterns, the effect of 

ecotones on species turnover patterns (though 

somewhat reduced in the Smoky Nountains) , and 

the pattern of species anplitudes on the gradients. These similarities imply that there 

is some generality to certain structural 

features of predominantly migratory temperate forest bird communities. In sae of these 

same ways, both communities are quite diff erent from tropical forest ones as discussed previously (Able and Noon, 1976) . Most 

notably, the apparent absence of altitudinal 

segregation of putative competitors suggesting interference competition, and the 

large changes in community composition coincident of ecotones are in sharp contrast to 

the patterns described by Terborgh (1971), 

Terborgh and Weske (1975) and Diamond (1973) 

in two widely separated tropical areas. 

In many ways the differences between 

the communities of the two areas are more 

interesting than their similarities. Wherees species richness was very similar, the 

camunities in the Smoky Mountains were more 

extensively dominated by one or a very few 

species. This difference was not accomplished at the expense of the abundance of 

t5e rarer species. In fact, abundances of 

most species averaged higher in the Smoky 

Momtains than on the northern gradients 

and this difference was merely greater in 

the dominarats. ~abenold's (19 76) data reveal 

t%e same difference which he attributed to 

duced competition in the depauperate 

autkern fauna. Our data don't admit this 

explmation, but there are other possibilities, none of which are yet tested. The 

breedbg season is elongated in the southern 

mountains, allowing mare double-broadedness and at least the potential of staggering breeding and thereby reducing competition. Differences in resource abundance, 

variety or temporal availability between 

the two regions could also effect changes 

in the competitive regirne. 

If competition across the commity is 

relaxed in the southern mountains (and we do 

not assert that this is generally so), both 

the higher abundances of species and the 

smaller turnover of species at ecotones could 

be explained. Distributional boundaries 

coincident with ecotones are likely a product 

of habitat selection evolved and reinforced by 

competitive pressure. If ecotones were less 

sharp in the Smoky Mountains our results with 

regard to distributional limits would be explained. However, we have no evidence that 

this was the case. In addition, it must be 

emphasized that whereas a smaller proportion 

of species limits occurred at ecotones than 

in the Northeast, large changes in the relative abundance of species were still obvious. 

If we examine the species which are dominants at various elevations on the Smoky Momtain gradient a comon characteristic emerges. 

The most abundant species are also those that 

occupy the greatest elevational ranges on the 

gradient. The list of these abundant and 

broadly distributed species includes both migrants and residents, low- and high-elevation 

species, representatives of at least five 

families, and a variety of trophic specializations. The only feature they appear to have 

in common is that they are habitat generalists. 

This relationship between "niche" width 

and abundance has been found in several kinds 

of communities , including birds (McNaughton and 

Wolf, 19 70; but cf, Ricklefs , 1972) . The causal 

factors in this relationship are by no means 

clear although it seems reasonable that species 

with broad habitat tolerances could reach and 

maintain larger local populations 

A final major difference between the communities on the two gradients is the ratio of 

migrants to regional residents. Superficially, 

the Smoky Mountain avifauna is more similar to 

a tropical one. However, many of the individuals of these species move at least to lower 

elevations in winter and those that do not 

apparently wander extensively (S tupka, 1953). 

Thus they are not sedentary in the sense that 

many tropical species are thought to be (e-g., 

Diamond, 1973; but cf. Karr, 1976, and references 

cited therein). Because in both areas virtually 

all individuals occupy their breeding territories 

for only a small fraction of the year, interspec&fic territoriality leading to the repulsion interactions described by Diamond (1973) 

and Terborgh (1971) may be impractical. As we 

argued previously, competitive pressures in 

these migratory temperate communities seem to 

have been resolved primarily through differential 

habitat selection. Under these conditions overt 

evidence of competition may be leacking as shorn 

theoretically by Rosenzweig (MS), and empirlcally by Noon (19 77) . 

Differences in community-level patterns 

reflect differences in population-level responses. Even if these distinctions are slight 

they may have important consequences for effective habitat management. If southeastern 

species are more generalized than their northeastern counterparts then they should be less 

adversely affected by specific changes in habi- 
tat structure. On the otherhand, if southeastern species diversity is limited by 

peak resource abundance then at tempts to 

increase local diversity by increasing local habitat heterogeneity will have only 

limited success. 

Variability in a species' habitat selection my imply behavioral plasticity in 

response to proxinrate cues used to assess 

habitat suitability. Specificity of habitat 

selection in any one locale my by in response to interspecific aompetition (Noon, 

1977) or simply to a lack of alternative 

suitable habitat. Effective habitat management for a specific species will depend 

upon accurately ascertaining these subtle 

influences. Managing structural habitat 

components to positively influence a particular species will most likely have negative influences on other species. The challenge for the habitat manager is to minimize 

these negative repurcussions. 

Present land-use practices often result in the generation of small blocks of 

forest. The dramatic consequences of this 

forest fragmentation on avian communities 

has recently been reported (Whitcod, 1977). 

Although these fragments contain patches of 

habitat structurally appropriate for certain species, those species are absent invariably these species are neotropical migrants which appear to be extremely sizesensitive. Proper management to insure the 

presence of these species means not only 

insuring appropriate habitats but that these 

habitats be contained within large tracts of 

continuous forest . 

The analysis of the thrush habitat select ion pat terns have demonstrated the use 

of a multivariate analysis technique and its 

potential application to habitat management 

schemes. For example, using the results 

of discriminant function analysis a given 

location within a forest could be measured 

using the same subset of variables as were 

used in the habitat niche descriptions of 

the thrushes. Subsequent to plotting this 

point in discriminant space the locat ion 

could be assessed according to its probability of containing a particular thrush 

species. If the forest site were not contained within the probability ellipse of 

the desired species, or if it would not support the theoretical maximum species complement, then, & , the habitat could be 

altered to include this (and other) species. 

An area with high structural diversity should 

generate a point in discriminant space that 

would simultaneously be contained within the 

probability ellipses of several species 

The consequences of habitat perturbations or successional changes would be reflected by mvement of a forest's mean h~,itat 

vector in discriminant function space. hy 

habitat alteration which would mve the mean 

vector closer to a species' centroid should be 

beneficial to that species since the population 

would have rnore suitable habitat available (Anderson and Shugart, 1974). Conversely, movement 

away from a speciesf centroid should have a negative effect on its population size and if moved 

sufficiently could cause local extinct ion. 

The accuracy with which predictions of population change can be made depends upoc the 

regularity of a species ' habitat select ion pattern fndependent of changes in its competitive 

environment The more invariant a species ' 

habitat selection the more accurately its population dynamics can be modeled. The results 

presented above represented a test of the generality of habitat selection of the northeastern 

montane thrush guild. They indicate that subtle 

changes in a species environment may generate 

substantial niche shifts. The successful management of avian wildlife will require a detailed understanding of the species' habitat 

requirements as well as the dynamics of its 

lnteractions with the rest of the community. 

Our data indicate that changes in comunitylevel attributes may generate significant 

changes in a species-habitat utilization. 

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cornunities in the Great Smky Mousttains. 

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1969. An approach to the study of ecological relationships among grassland birds. 

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1975. Avian comunit ies , energetics , and 

functions in coniferous forest habitats. 

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of forest and range habitats for nongame 

birds. U.S. Dept. Agr. Forest Serv. @en. 

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19 74. Avian cornunity organization and habitat structure. Ecology 55 :1017-1029. 

Yeaton, R.1. 

1974. An ecological analysis of chaparral 

and pine forest bird communities on Santa 

Cruz Island and mainland California. 

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Webesday A£ eemoon , January 25 

Specialized Bird Habitats and Management 

Mode rat or : J . W . Hardy 

Florida State Xuseum 
Snag Management for Cavity Nesting Birds 

Richard N. ~onnerl~ 

Abstract.--Availability of snags on forest Lands affects 

abundance, diversity, and species richness of cavity nesting 

birds. The effect of timber rotations, harvestdng techniques, 

and fungal heart rots on nest site availability is examined. 

Research needs are surveyed and management recomendaeions 

suggested. 

INTRODUCTION 

Increases in availability of snags on 

forest lands hdve been shown to increase the 

abundance, diversity, and species richness of 

cavity nesting birds (Balda 1975b). If forest 

management is to favor these species and the 

production of snags as suitable nest sites, it 

must consider length of timber rotation, harvest techniques, fungal heart rots, and bird 

species, 

This paper examines interactions that affect production of suitable nest sites and 

offers management recornendations that could 

increase snag availability. 

SNAGS ASD SNAG USE 

In this paper, a snag will be defined as 

any dead, dying, or living tree suitable as 

a nest site for a cavity nesting bird. Snags 

are produced naturally by a variety of environrnental factors, all of which stress and 

kill living trees. Fire, tree disease, 

lightning, flooding, and drought are some of 

the more obvious forces that stress trees 

(Re~n 1955). 

Birds use snags for a variety of purposes, Woodpeckers, chickadees, nuthatches, 

and brown creepers (Certhia familiaris) commonly use snags as foraging substrate, Flycatchers, shrikes, red-headed woodpeckers 

) , bluebirds, snd 

hawks regularly use open-area snags as 

perches to watch for prep. Many species of 

L/ Research Wildlife Biologist, USDA 

~oresF Service, Southern Forest Experiment 

Station, iiildlife Habitat and Silviculture 

Laboratory, Nacogdoches, Texas, in cooperation with SC~IGOL of Fores;r.i, Stephen F, 

Austin State University, Kacogdoches. 

passerine birds that occupy edge or open habitats use snags as singing perches for territorial advertisement, Woodpeckers often use 

resonant undecayed portions of snags as drarming sites for territorial announcements. 

Primary cavity nesters, such as woodpeckers, typically excavate their own nest 

and roost cavities in snags, Secondary 

cavity nesters use natural cavities and abandoned woodpecker excavations (Table I). For 

example, owls often use woodpecker cavities 

as daytime roost sites, occasionally before 

they are vacated by woodpeckers (Gonner 

1973). Therefore, factors that cause trees 

to become suitable, potential nest sices for 

primary cavity nescers are che most important 

management parameters in snag production. 

Natural cavities and woodpecker excavations are also used by animals other than 

birds (Gysel 1961, Kilham 1968, Dennis 1971, 

Erskine and McClaren 1972)- Squirrels, mice, 

wood rats, bats, raccoons (Procyon lotor), 

and oposs~m ( )%G-- 

cavities for winter and sumer dens, Less 

noticeable residents are various species of 

funnel-web spiders, skinks, and tree frogs. 

Cavities provide dry shelters for these small 

predators as they wait for insects (Conner 

1974). 

SUIT-ABILITY CF SNAGS AS NEST SITES 

Recent studies denonserate that even 

prlnmry cavity nesters cannot nest irr j usr 

any tree, These birds largely depend upon 

trees infected by fungal heart rots; such 

trees have softened heartwood that makes ic 

easier for the birds to excavate a cavity 

(Odmn 194la and b, Steirly 1957, Shigo and 

Kilharn 1968, Dennis 1969, Ligon 1970, Kilhrahn 

1971, Conner et al, 1975, Crockett and Hadow 

1975, Conner et al, 1976, Jackson L977b). 
~';hle 3,--Scl.~ticd list of cavity nesting birds (Robbins et al. 1966, Dennis 1971, Erskine and 

nlctaren '13: ', ?lowbray and Cclertz 1972). 

Primary or 

S:iecj es secondary Specific references on nesting sites 

----- -- cavity nester 

secondary Bent 1923, Bellrose et af. 1964. 

America:~ Kestrt-I secondary Bent 1938 

(Palrfs --- ~"it ~ti~) 

secondary Bent 1938 

Cornmor3 F J ie'rcer primary Burns 1900, Bent 1939, Conner et al. 1975, Conner et 

allratus) --- al. 1976, Conner and Adkisson 1977. 

Pi1 eat ed ".;ocd;le 2 krr primary 

(Drvoco~la~~ -= ---- --I--- a 11 <: sa~i~s) 

Bent 1939, Hoyt 1957, Conway 1957, Jackman 1974, 

Conner et al. 1976, Conner and Adkisson 1977, Bull 

and Meslow 1977. 

R.r*d-be 1.1 ieb :liol~~Jpcckcr primary 

(-!f$j2)nerpe-s car~slj~~~~) 

Bent 1939, Reller 1972, Jackson 1976. 

Bent 1939, Reller 1972, Conner 1976, Jackson 1976, 

Conner and Adkisson 1977. 

~el.l~w-bcllli edSapsucker primary 

i Sp1a;irapi $-ut; varius) 

Bent 1939, Kilkan; 1971. 

Ilai ry Woodpecker p clrnary 

(g&~ide~ vill OSI~S) 

Bent 1939, Lawrence 1966, Kilham 1968, Conner et al. 

1975, Conner et al. 1976, Conner and Adkisson 1976, 

1977. 

Downy Wc~odpeckcr primary 

(~~co.id~:~ j>!~besc-g~) 

Bent 1939, Lawrence 1966, Conner et al. 1975, 

Conner et al. 1976, Conner and Adkisson 1976, 1977. 

Rpd-coeknded 'loodpeekizr primary 

c:Ercide? h~>~-eal-isi 

Bent 1939, Steirly 1957, Ligon 1970, Thompson (ed.) 

1971, Jackson 1977a and b, Kilham 1977. 

Great Cres ted Fi c7t:atc'ner secondary Bent 1942. 

(P&ia.rchtx ~~~i~~it~~s~ 

Tree Swallo'i.~ secondary Bent 1942. 

Bl at-k-cappel and Carolina both Bent 1946, Odum 1941a and b. 

Chicakdees 

Ipxrus 2 

and P. caro15rtens-i~~) 

Tuf red 'Ti%mt:use 

(Partis bi cdor> 

l&ite-breaste~i~ Red-breasted, both 

and Browrt-headed N~athatches 

Bent 1946. 

Bent 1948. 

Br~wn Creeper secondary Bent 1948. 

(Cer~h --- La f amrliarisj - 
Table 1.--Continued 

Primary or 

Species 

3 

secondary Specific referenczs on ~esring sites 

----- 

Carolina Wren secondary Bent 2948. 

ludovic ianus) 

Eastern Bluebird 

(Sialia sialis) 

secondary Bent 1948, Conner and Adkisson 13744, Pinkowski, 

1974. 

Many of these studies also suggest that 

woodpeckers can excavate nest cavities in nuninfected trees. In such studies, however, 

the presence of fungal fruiting bodies on 

tree exteriors was relied on to indicate 

heart rot. But species of fungi that cause 

primary infection of heart rots do not typically fruit on the exterior of nest trees, 

and in many cases there is no other sign of 

decay on the outside of a nest tree with 

heart rot (Conner et al. 1976). In such 

cases, aseptically removed chips of heartwood 

from the tree core near the nest cavity should 

be cultured in the laboratory to check for 

fungi. 

SEQUENCE OF HEART ROT INVASIONS 

Heart rot fungi commonly enter through 

dead branch stubs (Hepting and Chapman 1938, 

Baumgartner 1939, Conner et al. 1976), but 

can also enter through tree bark damage. 

Wind-blown spores then come in contact with 

favorable growing conditions (Shigo and Larson 1969). 

Once a fungus has entered a tree it 

usually decays a small area and then spreads 

throughout the heartwood. Woodpeckers apparently detect heart rot by pecking the tree 

and distinguishing a particular resonance 

(Conner et al. 1976). 

Woodpeckers often start cavities but may 

abandon an excavation sire when sound, undecayed heartwood is encountered (Conner et al. 

1976, E. L. Bull pers. corn.). Jackson (1977b) 

has suggested that red-cockaded woodpeckers 

(Picoides borealis) excavate nest cavities 

slowly in areas where suitable potential 

nest trees are lacking. The woodpeckers can 

only excavate until they reach sound heartwood and must wait for fungal activity to decay wood tissue. In such cases, excavation 

may take more than a year. 

IDENTLFLCATIOX OF POTENTIAL XEST TREES 

Potential nest trees fcr primary cavity 

nesters arc those infected wich "top rots," 

heart rot fungi that invade the trunk or main 

limbs in upper regions of the tree. Lf d tree 

is to be classified as a suitable, potential 

nest tree, heart rot must be detected at the 

range of heights and stem diameters where 

woodpeckers normally nest (Table 2). Possible existence of suitable nest site conditions could be detected h>- observing: 

1. Fungal conks (fraiting bodies) of 

species known to cause heart rots 

(Shigo and Larson 1969, Hepting 1971, 

lviiller 1872, Conaer et ale 1976). 

2. Dead branch stubs (Shigo and Larson 

1969, Baumgartner 1939, Corlncr et al, 

1976). 

3. OIJ wounds or scars on trees resulting f ron mechanical, lightning, or 

fire damage (Hepting 1935, Repting 

and Wedgcock 3.937, Stickel 1940, 

Toole 1959, Shigo and Larson 1969). 

With sufficient time butt rots will 

grow high enough in the heartwood of 

trees to create suitable nest site 

conditions (Toole 1959). I 

4. Discolored or s~ft, decayed wood in 

increment borer corings (Toole 2959, 

Shigo and Larson 1969, Conner et al. 

1976, Jackson 199%) . i 

5. Existing woodpecker holes or cavities, i 

6, Obvious dead portions of trees. I 

7, Testing "Le tree with a ""~~igometd 

--Northeastern Forest Experiment 

Station--photo story No. 29, Upper 

Darby, Pa, 19082, 
Table 2.--Nest site characteristics of several primary cavity nesters. Values presented are a 

subjective estimate of optimal conditions based on data in the literature (see individual 

species list, Table I). CAUTIOS--These values will vary for tree species and geographical 

areas different from those where initial data were collected. 

Tree Preference for DBB of Age of 

Species Nest cavity diameter live or dead nest nest 

-- height (m) at nest (cm) s~tian oftrees' tree (cm) tree (yrs.) 

Red-cockaded Woodpecker 3-12 unavai 1. 

in lit. 

live 26-60 70-100 

Downy Uoodpecker 2-11 14-30 dead (both) 17-60 60-70 

Hairy Woodpecker 3-1 7 20-40 both 22-60 85-95 

Red-bellied Woodpecker 3-18 15-35 dead (both) 30-7(j2 60-2002 

Red-headed Woodpecker 4-20 24-36 dead (both) 70-1103 140-.300 

Common Flicker 3-18 26-60 dead (both) 30-120 60-300 

Pileated Woodpecker 5-17 30-45 both 35-85 100-180 

Black-capped Chickadee 2-9 9-15 dead unavail. unavail. 

in lit. in lit. 

- This parameter shows extreme geographic variation. 

- Conner, unpublished data in oak-hickory timber type (n = 4) 

- Based on mature oak-hickory wood lots--values probably less in southern pine types. 

8. Identification of fungi from culture 

of wood obtained by coring trees 

with an increment borer (Davidson et 

al, 1942, Nobles 1965, Conner et al. 

1976. 

Conks on the outside of a tree do not always indicate a heart rot, and thus a potential nest tree, Sap rots which infect and 

kill living xylem and phloem tissue also 

produce conks. The condition of the sapwood, 

however, may influence suitability of trees 

as nest cavity sites for certain species. 

Downy woodpeckers (Picoides pubescens) and 

common flickers (Colaptes auratus) in eastern U.S, rarely excavate nest cavities in 

oaks (Quercus spp.) and hickories (Carya 

spp.) with a living cambium at the nest 

areas. Eastern pi1eated (Dryscopus pileatus) 

and hairy (Picoides villosus) woodpeckers 

often excavate through a living hardwood 

cambium to reach a decayed heartwood core 

(Conner et al. 1975). Downies and flickers 

apparently need sap rots to soften outer 

portions of trees as well as heart rots when 

hardwoods and possibly pines (Pinus spp.) are 

used. 

EFFECTS OF TIMBER MANAGEMENT ON 

NEST TREE PRODUCTION 

Rotation time, or time between clearcutting, affects nest tree production, At 

present, rotation times are often established 

to maximize timber production and minimize 

loss of products to decay and similar factors 

(Hepting 1971). Short rotation times that 

maximize timber production may reduce the 

chance of trees growing large enough to 

house nest cavities (Table 2). Sufficient 

time must also pass to allow fungal heart 

rots to adequately decay trees. However, 

there is no information available to define 

the time needed for various heart rot fungi 

to decay trees to the extent required for 

nest excavation. 

Based on U.S. Forest Service guidelines 

(Forest Service Manual, Section 24-10, and 

24-15) rotation times for pines on National 

forest lands in southern forests are about 

65 to 70 years. At that age stands range 

from 40 to 55 cm dbh depending on site condition and can be used for pulpwood and/or sawtimber. When this dbh range is compared with 

trees selected as nest sites by the seven 

woodpecker species, the Forest Service 
rotation scheme falls within the dbh ranges (Bull and Heslow 1977). Factors used in the 

used (Table 2). Nest trees are apparently calculations include: (A) maximum bird species 

being produced. However, only the downy, red- density in pairs per square mile, (B) nruxber 

bellied, and flicker nest regularly in trees of snags used annually for nesting and roostyounger than 65 to 70 years. This suggests ing, and (C) a reserve of snags: 15 for each 

that more time is needed for trees to become one used. These three figures are then multisuitably infected with fungi. plied times each other (A x B x C = P), where 

Y equals the number of suitably sized snags 

A study of Fomes pini in southern pines required per square mile by the species, 

demonstrates an increase in fungal activity 

with age (Bepting and Chapman 1938). Only 

one out of 40 trees was sufficiently infected 

with rot to be culled after 80 years, ten 

years beyond the Forest Service rotation for 

southern pines. Forest Service rotation on 

bottomland hardwoods is 100 years, perhaps a 

bit more favorable for cavity nesters. 

Rotations practiced by private paper 

companies are shorter than those set by the 

Forest Service. Where southern pines are 

managed for pulpwood production, rotations of 

20 to 30 years are preferred (Johnson 

Slusher and Binckley 1974). If both pulpwood 

and sawlogs are desired, rotations are 35 to 

40 years. 

Timber harvest techniques also influence 

cavity nesters. In the National Forests of 

southwestern Virginia, snags and nest trees 

were left standing during clearcutting operations and a variety of wildlife used these 

trees: bluebirds (Conner and Adkisson 1974a), 

woodpeckers (Conner and Crawford 1974, Conner 

et al. 1975), and red-tailed hawks (Buteo 

j amaicensis) (Conner and Adkisson 1974b) . Ages of these stands when clearcut ranged 

between 100 and 150 years (Conner unpublished 

data), apparently a sufficient time for fungi 

to create suitable nest sites. However, 

snags are highly susceptible to fire and have 

the potential to fall; they are therefore 

considered undesirable by many forest managers 

(McClelland and Frissell 1975). 

Firewood collections on national forests 

remove many snags. The Forest Service occasionally opens up sections of land so that 

the public can pick up or cut any dead or 

fallen trees at no cost. Ln areas where nest 

sites are limited, such practices should be 

discontinued if cavity nesters are to be 

favored. 

CALCULATIONS OF mNIm SNAG DENSITY 

Several formulas have been devised to 

calculate the minimwn snag density needed by 

a cavity nesting species. Based on data collec ted in Arizona, Balda (19 75a) calculated 

the number of snags needed to support secondary cavity nesters in ponderosa pine (Pinus 

ponderosa) forests. The Forest Service has 

developed guidelines for additional formulas 

If the timber on an area is to be cut, 

the number of snags to be left can be calculated with the following formula (Bull and 

Meslow 1977) : S = T(L-R) + Y 

Where S = number of snags to be left per 

square mile 

T = years to next harvest 

L = annual snag loss per square mile 

R = annual snag recruitment per square 

mile 

Y = number of suitably sized snags 

required. 

Snags fall, and a sufficient number should 

be left to insure an adequate supply for cavity nesters until replacements become available. When leaving snags it is best to choose 

those that will last the longest (McCleLland 

and Frissell 1975) as well as those with 

cavities that are of immediate use. It should 

also be noted that snags in clearcuts benefit 

species that select open environments but do 

not favor cavity nesters that require deep 

woods habitat. 

ARTIFICIAL PRODUCTION OF NEST TmES AND SNAGS 

Nest trees and snags could perhaps be 

created artificially during timber harvest 

operations and in uncut forest stands, Silvicide injections are often used to kill 

unwanted trees during clearcutting to eliminate competition for light, moisture, and 

nutrients. 

Research is needed to determine if heart 

rot fungi are inhibited by the silvicides. 

The effect of silvicides on insect invasions 

as well as toxicity to wildlife (e.g. dioxin 

in 2,4,5-t) also needs to be examined since 

snags are regularly used as foraging sites. 

Several studies have already shown that certain herbicides have a toxic and teratological effect on insects, wildlife, and the 

ecosystem (Orians and Pfeiffer 1970, Galston 

1471, President's Scientific Advisory Corn. 

1971, Westing 1971, Moffett et al. 1972, 

Morton et al. 1972, Lichtenstain etal. 1973, 

Wilson 19 73, Kenaga 1974) . 

If silvicides do not prevent production 

of suitable, potential nest sites and do not 

harm wildlife, injections might be made in uncut stands and during lumbering operations to 

increase snag density. 
Frill girdling of trees and inoculation 

with sap rots may be an alternative method of 

eliminating unwanted trees and making nest 

sites. 

Artificial nest sites night be produced 

even more rapidly through a technique suggested by Affeltranger (2 Thompson (ed.) 1971). 

Trees could be bored and possibly inoculated 

with an appropriate species of fungus at 

heights and positions where woodpeckers normally excavate nest cavities (Table 2). Consideration must be given to the orientation of 

woodpecker nest entrances (Burns 1900; Bent 

1939; Lawrence 1966; Dennis 1969, 1971; Baker 

- in Thompson (ed.) 1971; Kilham 1971; Reller 

1972; Conner 1975; Inouye 1976; Conner 1977). 

Bore holes should be placed on the underside 

of leaning trees so that the openings point 10 

degrees below the horizontal (Conner 1975). 

The preference of individual woodpecker species 

for either live or dead sections of trees as 

nest sites must also be considered (Table 2). 

The general habitat requirements of 

cavity nesters should be considered when artificially creating nest trees. Treated trees 

should be located in habitats with basal areas, 

vegetation densities and heights, etc., that 

are acceptable for a particular cavity nester 

(See references in Table 1). 

MAGmENT RECOMMENDATIONS 

If forest management is to favor nest 

sites for cavity nesters, the following recommendations can be employed: 

1. If timber on an area is to be harvested, increase silvicultural rotation times 

to a minimum of 100 years for most cavity 

nesters, and to 150 years for the pileated 

woodpecker (benefits forest cavity nesters). 

(Note--total habitat requirements of individual 

species must also be considered.) 

2. When harvesting timber leave a sufficient number of suitable snags for present 

and future use by cavity nesters (See Bull 

and Neslow 1977) (optimizes open area cavity 

nesters) . 

3. If timber is not to be harvested, 

manage the area as wilderness (optimizes 

mature forest cavity nesters). 

4. Discontinue removal of dead, dying, 

and decayed trees for use as materials or 

firewood in areas where nest cavity sites are 

limited. 

6. Pending results from further research, 

bore holes in suitably sized trees and inoculate with a suitable heart rot fungus. (Local 

bird clubs could help in this management 

practice.) 

7. When managing for Fndividual species, 

be aware of specific nesting habitat (basal 

area, vegetation density, etc.) and nest tree 

requirements, i.e., living, dead, top broken 

off, etc. (See references for individual 

cavity nesting species, Table 1). 

RESEARCH NEEDED 

Further research is needed on the following subjects before snag management for cavity 

nesters can be optimized: 

1. Determine the fungi species responsible for producing suitably decayed nest trees 

in southern forests. 

2. Investigate the utility of silvicide 

injection and frill girdling as methods of 

producing suitably decayed trees for cavity 

nesters. The effect of silvicides on fungal 

heart rots, insects, wildlife, and the ecosystem must be determined. 

3. Determine the time period necessary 

for each particular sap and heart rot species 

to invade and suitably infect different tree 

species. (See Toole (1959), butt rot invasion 

sequence versus time. ) 

4. Determine the effectiveness of bore 

holes and subsequent inoculations with an appropriate fungi species for artificially 

creating suitable nest trees. 

5. Determine how long snags of various 

tree species will remain standing. 

ACKNOWLEDGMENTS 

I would like to thank Evelyn L. Bull, 

Jerome A. Jackson, and James C. Kroll for 

reviewing the manuscript and making many excellent suggestions . 

5. Create suitable nest sites by frill 

girdling trees and inoculating them with sap 

rots. 
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2 

:laie~lrn G. EdwardsKostract.--Lnterest in rsptors and their pseservztion 

has resuited in state and federal laws protecting them from 

trapping, shooting an? poisoning. While Kany of man's activities are destructive, some can be ~odified to lessen 

their inpact on raptors. 

Until recent times, the white man has 

considered all raptors vermin and they were 

shot, trapped and poisoned, This persecution resulted from competition with man 

for prey species and from occasional forays 

into domestic birds and animii,ls, As more 

information on the predatcr-~rey relationship was disseninated, the farmer and 

the hunter slowLy changed. The crash in 

the population of many hawks due to the 

widespread use of toxic insecticides in 

the 40's and 50's attracted the attention 

of bird fanciers, biologists and other 

groups. Consequently, state and federal 

laws were passed protecting raptors. 

The goal of raptor management is 

difficult to define. It has been 

characterized as having three points of 

view: economic, recreational and 

scientific (Snyder 1975). In the Southeast, 

most poultry is raised under cover and 

direct losses to farmers are slight. Commercial shooting preserves, however, may 

have serious problems with individual 

red-tails and Cooperfs hawks. Iqoost important are the economics of preserving 

habitat threatened kg developers . Recreat ion needs vary with nature enthusiasts 

wanting many species in a natural setting 

while falconers are pri~arily interested in 

the larger aecipiters, buteos and falcons. 

With a few exceptions, management has 

consisted mostly of protection from shooting, disturbance and poisons. In many cases 

this protection is sufficient to sustain a 

viable populaticn, More comprehensive management strategies have been developed for the 

bald eagle (~hthieson et. al. 1977) and the 

peregrine falcon (Cade lg?~a!. A proposal 

for saving an endangered or threatened population has been developed (Olendorff and 

S toddart 13711). 

The management of raptors sometimes 

seems futile due to their mobility. If conditions are unsuitable in one place, they 

simpPj move until they find what they need. 

However, manipulation of habitat, urban 

growth and other activities of man have reduced the total habitat, The more adaptable 

red-tailed hawk has not been affected as much 

as the less adaptable bald eagle. The bird 

hawks (peregrine falcon, Cooper ' s and sharpshin hawk) have suffered heavy losses due to 

the ingestion of toxic chemicals. 

Soole species of raptor is found in almost 

all situations, including the center of large 

cities. The impact of man's activities on 

raptors results from-- 

- l/Paper presented st the workshop 

on Management of Socthern Forests for 

Nonga~e Birds, Atlanta, Georgia, 

Jan~ary 24-26, 1978, 

2JWildlife Section Head, Socthern 

~e~io;, U. S, Forest Service, 1720 

Peachtree Street, ?T, W,, Atlanta, 

Georgia 30309. 

--pollution of water, 2 

channelizat ion 

--urban sprawl 
Timber !tanagerLen t 

Timber manage~ent lay dar8ge or ennazce 

habitat, depending on i?:e type GI c-~t 2nd tke 

raptor, A newly cut tix3er stand is rich Ln 

passerines i~oo-ger 1967) and snali nxxals 

and attracts the accipiters acd S325eeos. Bcwever, most buteos and cwls need large, ~ature 

trees for nesting ftnd perching. Screech cwls 

and kestrels nest in tree hollows, usuzlly 

found in mature or overrcature timber, A nliiTber of safeguards can be built into tixbe~ 

sale operatiom to protect raptors acd maintain suitable habitat. 

When a stand of tinber is re~enera%e? or 

has an intermediate cut, all known ac? lye 

hawk and owl nests should be tied into a 

special zone such as a water inFluence zone 

or into a elmp of trees being retained for 

future den trees. If any of the historical 

peregrine falcon eyries becoxe active, timber 

operations should be stopped witklc 1/2 mile 

of the base of the cliff during the nesting 

period of !larch l through June 313. E~ecial 

considerations are unnecessary when eyries are 

inactive. To encourage raptors, et leastcce 

perch tree for hmting should be retained in 

each 5 acres of cuto-rer area. Preferably tkis 

will be a den tree. In stands where prescribed burning nay be practice<, a Large 

healthy pine should be retained. Vith most 

agencies and many commercial timber managers, 

it is custonary to leave strips of trees 

along streams and lakes. The larger trees in 

these strips are important for eagle and 

osprey nesting. As large dens develop slowly 

and are critical to some of the owls, all den 

trees with an opening of 5" or over shor;ld be 

retained, regardless of location, 

A balance of age classes and tiir;oer tmes 

with good dispersion of both will prcvi.de 

habitat for mny raptors. Pure stands of pine 

provide very little for raptors sc both upland 

hardwoods and bottomland hardwood stringers 

are needed. An exception is newly thinne2. 

and Surned pine stands which are known to be 

used by golden eagles, In site preparation 

prior to seeding or planting, +en and perch 

trees, buffer zones and otter key sress must 

be protected, In planted pine stands, wider 

planting intervals &re preferre2 Feca-~se the 

grass and forbs growing between rows prcvide 

better habitaf for small ~il~a5s. 

present level or re4ucei. An;: cutting will 

be by the selec5ion xe~h35, Activities such 

as tircFer kar-resting, c7~15urai imprcve~ents 

an3 roa? ccnstructioz vill cct be conducted 

within ore-half ~ile ofnes5s 3uricg the time 

of egg laying, icezbatlon ~nd fhe first month 

after tatching i Cbmkerlain 1971). 

Shoot Lng 

While most raptors are protected by both 

state and federal law, many are s5Lll crippled 

and killed by gunshots each year, The Eagie 

3ehabiTitation Cefiter at kabzrn University 

received 5 crippled eagles in 1971, Generally crippled birds are picked up by state 

or federal law-enforcexent personnel and 

taken to a veterinarian or falconer who is 

interested and has a pmit for reha,biLitation, No one knows how Kany are shot and 

left. There is no questioc though, that 

shootin6 is on the decline due to law enforcement an2 education. 

There sre many indi-~iduals , including 

veterinarians, who are interested in rehabilitating raptors. In some cases, the 

"rd can be returned to the wild. Disposition of the others which are permanentiy crippled froa gunshot wounds is a 

problem, Kcst zoos and museums have all 

they want and some of these volunteers 

find thenselves keeping 5 or 6 hawks and 

owls on a permanent basis. Euthanasia is 

the onLy practical solution but is very 

distastef:d. Rehabilitating the more 

common hawks and owls is not really practical, but himan nature being what it is, 

these efforts will continue. 

Water Pollution and Channelization 

Water pollution, channelization and 

dredging affects both eagles and ospreys by 

reducing the s~~pply of fish. Studies have 

shor;~~, a reduction of 68% of tke fish population in channelized stremss (~arplee, 

Louder, Weber 1971:. Investigations have 

also showc that fish from polluted waters 

ictroducz toxic chemicels Lntc these biras 

(Pxony-mous 1~79)~ 3redging and thermal 

pollutioc alsc h8ve far reaching effects 

in reducirg the fis"opu1ation (smith 

1971j, tj'anmede reservoirs, however, may- contribute to the habitat of ospreys and eagles. 

Bald eagle nesting sites require pro- 'Jrbar, Sprainnl 

teetion. In tke absence of a survey of 

territory size, G tentative area cf 1212 acres The preenlption of forests a~d fields 

has been assumed on Southern Forests (u, S, far factories and subdivisions has caused 

Forest Ser-rice lg?Lf, Within this zone, land probie~s for many reptors es it reduces 

use practices that alter habitat are Fro- their tokal ha7~Ltat. Gn the other hand, 

hibited, Disturbance will be held to the the irterstzte sgsterr, thzt has accompanied 
this development has ixrproved conditions 

for the red-tailed hawk, The seeded cuts 

and fills are prime habitat for cotton rats 

and other small mwads and few people will 

shoot from or across an interstate, Here 

in Georgia, a wintering red-tail for each 

linear mile of interstate has been noted 

often. Conversely, screech and barred owls 

seen; particularly susceptible to being 

struck by automobiles. 

Pesticides 

There has been so much written about 

the effects of the toxic chemicals on raptors 

that this paper will not discuss this in detail. Although DDT is no longer used in 

this country, it is still a threat as it is 

widely used in South America and wintering 

raptors ingest these poisons with their 

prey (~incer, Sherburne 1974). A further 

threat is the return to North America of 

prey species which carry heavy concentrations of these dangerous chemicals. However, the problem doesn't seem as serious as 

it was when these poisons were used in the 

Continental United States. The number of 

immature arctic peregrine falcons seen and 

banded has remained static for the last 5 

years, indicating good reproduction. 

Falconry 

The number of raptors taken by falconers is insignificant, The birds kept 

are marked and replacements are closely 

monitored. To illustrate the extent of 

falconry in the Southeast, South Carolina 

has 3 registered falconers, Georgia has 12, 

Alabama has 3, and the practice is illegal 

in North Carolina. No falconer is permitted 

to keep more than 3 birds and only immature 

birds may be trapped. There is much interest in captive breeding of hawks and falcons 

for use by falconers. The drain on wild 

birds is quite small. 

mAru'GmEZi SPECIES 

Endangered raptors in the Southeast 

are the southern bald eagle and the eastern 

and arctic peregrine falcons, Other than 

captive birds in breeding projects, the 

eastern peregrine is apparently no longer 

present as a breeding population, The arctic 

peregrine is observed in large numbers in its 

fall migration down the Atlantic coast and 

in lesser numbers throughout the East. A 

breeding bird census of ospreys and bald 

eagles taken annually on Southern National 

Forests and adjoining lands shows an increase in number of nests and number of 

young birds fledged since 1972. 

DIRECT MEITAT INPROVBmBT 

Little has been done in the Southeast 

thet can be defined as a direct habitat improvement. For man;y years there has been a 

wintering population of 4 to 6 golden eagles 

in the high plateau along the Blue Ridge 

Parkgay on the Pisgah National Forest in 

Worth Carolina. The area is open country with 

scattered shrubs and trees and abundant cottontail rabbits and other small mamnals. Each ' 

year a part of this land is burned to retain 

the old-field stage of succession, This both 

perpetuates the large mammal population and 

keeps it open enough for eagles to maneuver. 

Studies are also being made on the practicality of creating tree dens in pole size timber with the use of a power drill. The premise is that dens started in young trees will 

be large enough for raptors and other den 

dwellers when the trees are 60 or 70 years of 

age. Natural large dens take much longer to 

develop. Artificial nest boxes have been 

successfully used by kestrels (~ammerstrom, 

Hammerstrom, Hart 1973) and screech owls, 

Plans exist for reestablishing peregrine falcons on historical eyries in the Southern 

Appalachians (~ade 1975a). Conceivably new 

artificial eyries may be created in suitable 

habitat where cliff faces do not provide 

natural ledges. 

For several years, a pair of golden 

eagles has wintered on the Lake Burton Game 

Management Area on the Chattahoochee National 

Forest in North Georgia where they are sustained on the carcasses of deer killed illegally or accidentally and gathered by the 

Game and Fish Commission. 

Artificial nest structures have been 

erected for osprey use but without success in 

North Carolina and Florida. 

Raptor management is new and few proven 

practices are known which result in increased 

populations. 

Raptors have been impacted for many years 

by the activities of man resulting in death 

due to shooting, poisoning and reduction of 

habitat and prey base. Timber management decreases habitat for some raptors and creates 

it for others. Modifications of timber operations can lessen this impact. Shooting and 
pesticides poisoning have decreased althoqh 

too late for the eastern peregrine falcon. 

The banning of toxic ~esticides, protection 

against shooting and education has resulted 

in stable and increasing populations of some 

raptors. 

Pinonymous 

1970. Bald eagles poisoned by mercury. 

Raptor Res. Mews 4: 70-71. 

Bent, A. C. 

1937. Life histories of North American 

birds of prey, parts 1 and 2, Smithsonian Institution USNN Bulletins 1-67 

and 170. 

Cade, li". J. 

1975a. Plans for managing the survival 

of the peregrine falcon. in Management of raptors, Hamerstrom, F. N., 

Jr., B. E. Harrell and R. R. Olendorff, 

eds. Raptor Res. Report No. 2, Raptor 

Research Foundation, Inc., Vermillion, 

South Dakota. p. 89-104. 

Chamberlain, E. burnham 

1974, Pare and endangered birds of 

Southern TJational Forests, USDA, 

U, S. Forest Service, 108 p. 

Hammerstrom, F,, F. N. Hm-erstrom and 

J. Hart. 1913. Nest boxes: an 

effective management tool for kestrels. 

J. Wildlife Mgt. 37: 400-403. 

Hooper, R. G. 

1967. The influence of habitat disturbances on bird populations. 

M, S. thesis, VPI & SU, Blacksburg, 

Va . 

Lincer, J. L., and J. A, Sherburne 

1974. Organocklorines in kestrel prey. 

J. Wildlife Mgt. 38: 427-434. 

Phthieson, John E., David J. Sorenson, 

L. D. Frenzel and T. C. Dunstan, 1917. 

f4anagement strategy for bald eagles. 

Trans. N. Paier, Wildlife and Nat. 

Res, Conf. 42: 86-92. 

Smith, S. F, 

1971. Effects of thermal pollution on 

aquatic life in an east Texas reservoir. 

Proc. Southeastern Assoc. Came & Fish 

corn. 25: 374-384, 

Snyder, Noel F. R,, and Helen A. Snyder 

1975. Raptors in range habitat. Proe, 

Symp, on Ygt, of Forest and Range 

Habitats for Wongame Birds, Tuscon, 

Ariz. p. 190-209. 

Tarplee, W. H., Jr., E. W. Louder, A. J. Weber 

1971. Evolution of the effects of 

channelization on fish populations in 

North Carolina's coastal plain streams. 

Proc. Southeastern Assoc. Gaae & Fish 

Corn, 25: 431-446. 

U. S. Forest Service 

1974, Wildlife habitat management 

handbook, First Draft. 

Olendorff, R. R, and J, W, Stoddart, Jr. 

1974. The potential for management of 

raptors populations in western 

grasslands. Management of raptors. 

Hmerstrom, F. M., Jr., B. E, Harrell 

and R. R. Olendorff, eds., Raptor Res. 

Report No. 2, Raptor Res. Foundation, 

Inc., Vermillion, S. D., p. 47-88. 
COM4OM SOUTHEASTERN UPTORS 

COmON Nils.& ZOOLOGICfi NAME 

Arctic Peregrine Falcon Falco peregrinus tundrius Migrant and occasional winter 

resident along all coast 

Barn Owl Tyto alba pratincola 

Barred Owl (~orthern) Strix varia varia 

Fields and sparse woods 

Oak-pine, oak-hickory, 

oak-p-cypress, white-redJack pine, maple-beech-birch 

Barred Owl (~lorida) Strix varia alleni 

Not restricted to any timber 

type 

Black Vuiture Coragyps atratus 

Broadwinged Hawk Buteo platypterus Oak-hickory, oak-pine, oakgm-cypress, maple-beech-birch 

Burrowing Owl (~lorida) Speotyto cunicularia Prairies of central and south 

Florida 

Cooper ' s Hawk Accipiter cooperi Broken woodlands of oakhickory, oak-pine, wkite-redjack pine, maple-beech-birch 

Everglade Kite 

Golden Eagle 

Rostrhamus sociabilis 

Aquila chrysaetos canadensis 

Swamps and marshes of Florida 

Winter resident, may be found 

in all types 

Great Horned Owl Bubo virginianus Oak-hickory, oak pine, oakgum-cypress, maple-beech-birch, 

white-red-j ack pine, sprucefir 

Circus cyaneus hudsonia 

Ictinia misisippiensis 

Marshes, fields and meadows 

including coastal areas Marsh Hawk 

Mississippi Kite Open areas in lowlands, oakgum-cypress, longleaf-slash 

pine 

Osprey 

Pigeon Hawk 

Pandion haliaetus carolinesis 

Falco columbaris 

Around lakes and reservoirs 

throughout Southeast 

Migrant and occasional winter 

resident throughout Southeast 

including coastal areas 

Red-tailed Hawk Euteo jamaicensis Field borders, oak-hickory, 

oak-pine 

Red-shouldered Hawk Buteo lineat us 

Screech Owl a as tern) Otus asio Fields and broken woodland 

oak-hickory, oak-pine, maplebeech-birch 
Screech Owl (~lorida) Otus asio floridanus 

Sharpshinned Hawk Accipiter striatus 

Shorteared Owl Asio flanrmeus 

Sparrow Hawk Flaco sparverius 

Southern Bald Eagle Haliaeetus leucocephalus 

Swallow-tailed Kite Elanoides forficatus 

Turkey Vulture Cathartes aura 

Peninsular Florida, oakhickory, oak-gm-cypress, 

longleaf-slash pine 

Broken woodland, oak-hickory, 

oak-pine, oak-gm-cypress, 

maple, beech-birch, sprucefir 

Fields, meadows, cut over 

areas in winter 

Fields, meadovs, coastal 

areas 

Coast and inland waters, 

nests in large pines 

Marshes and swamps, oak-gmcypress 

Not restricted to any timber 

type 

- ll~imber types from National Atlas, USGS, 1970. 
Wading Birds laad Wetiands Management 

Wary 1 i C, Landin- 

- ----- 

iibstuact.--,"ian~gerrtent.t of wet1.ant-l~ fox- wading birds is 

a lirrie known research area, Prior research has primarily 

been iiirecred r.oward est~tarine and ecastal areas. Freshwater wetlands in rhe Southern Cnited States have declined 

drarmtically in chr past 150 years, as have populations of 

the bird species dependent upon those arezs for habitat, 

Bman recreational activities, fill and drajn efforts, 

channelization, and dredging are primary causes of wetlands 

decline. P~sticides and poor water quality as well as the 

forementloned factors contributed to the decinlation of bird 

populations. Habitat development and management practices 

would benefit all rriarsh users as well as the 27 species of 

wading bird species discussed, Five management techniques 

are set Forth: (1) preservation and mar?agen;ent of all 

existing wetlands; (2) creation of new vetlands areas; 

(3) expansion of some temporary wetlands to permanent areas; 

(4) maintenance of high water quality; (5) year-round protection of wetlands areas from humans and predators. 

Management of wet Lands for wading birds 

is a little known research area which has 

historically not been given much consideration, 

This is especially true in freshwater wetlands, 

although research efforts have been made concerning protection and development of habitat 

in coastal areas by the U, S. Army Engineer 

Waterways Experiment Station (WES), the U. S. 

Fish and Wildlife Service (USFW3 j , the National 

Oceanic Atmospheric Administration (NOM) 

through the Sea Grant Program, the National 

Park Service, the Xatianal Audubon Society, and 

to a limited degree, some state conservation 

agencies, and private citizens. 

Past and present research by these 

agencies or groups have been tailored to meet 

the needs of each agency, The W%S srudies are 

nation-wide efforts to determine the extent of 

use (nesting, loafing/roosting, and feeding) 

of dredged material islands b3- colonial nesting 

sea and wading birds throughoue the United 

States coastal, riverine and Great Lakes waterways. Their objecti-re is the establishent of 

guidelines for managevent and development of 

these 20004- Corps-made islands (Landin and 

Soots 1977). 

- 1/ Biologist, Enviranaental Effects Laboratory, Waterways Experiment Station, P, 0. Box 

631, Vicksburg, Hiss, 39180, 

%?hr' t;Si"l+S Cc;as&~ 1 Ecus j stems Team is 

presently making a survey of Eastern and Guif 

Coast colonies of wading birds with the intention of mapping these colony locations 

(Portnoy 1977, Custer, unpublished data). 

Their objective is to be better able to 

protect the colonies through their refuge 

systems, land aquisitions, and other means. 

NORa through Sea Grant has sponsored 

research at state levels. The most outstanding study in terms of wading bird habitat 

management was conducted by Soots and Pnrnell 

(1975) in the North Carolina estuaries. 

State efforts have usually been in cooperation with state universities and have been 

more lucabized, site-intensive research 

(Williams and Hartin 1968; Ryder 1977; John 

Sniith 1976, Texas Parks and Wildlife, personal 

comunica t ion) , 

The I:ational Park Service has funded 

research efforts of Buckley and Buckley (1976) 

which has resulted in a general guidelines 

manual for protection of existing sea and 

wading bird colonies on the East Coast, 

The N&tional hudubon Society established 

sanctuaries for wading and sea birds years ago 

in key locations, Most of their protected 

areas have been coastal (Mills 1934, Dunstan 

1977) but a few sites are inland. These areas 

are generally only nestingfroosting sites 
however, and can offer no protection from destruction of feeding habitat outside the sanctuaries. Only when colonies of wading birds 

are established in large refuges with accompanying wetlands to ensure feeding habitat are 

they a successful and continuing entity. 

One hundred fifty years ago, before the 

intensive efforts to fill, drain, or dredge 

the wetlands and waterways, there existed in 

the interior Southeastern United States large 

expanses of freshwater swamps and marshes such 

as the Big Cypress snd the Everglades in 

Florida; the Great Dismal Swamp of Viginia; 

Grand Bay, Okefenokee and Altamaha Swamps in 

Georgia; White River Bottoms, Swan Lake, and 

Slovac Thicket in Arkansas; T'On Swamp in 

South Carolina; Reelfoot Lake in Tennessee; 

and the Tensas Bottoms of Louisiana (Goodwin 

and Niering 1971, Niering 1966). These areas 

still exist today on a much reduced, altered 

scale. However, there had also been numerous 

other smaller wetlands scattered throughout 

the South that have totally disappeared through 

fill and drain efforts for farmland or city 

expansion, 

These freshwater wetlands had supported a 

large and varied wildlife population, not the 

least of which were tremendous colonies of 

eleven species of herons, egrets, ibises, and 

cormorants that nested at Reelfoot Lake, Swan 

Lake, Okefenokee Swamp, the Everglades and other 

suitable areas (Audubon 1944, Bent 1926, 

Meanley 1972). In addition, they provided 

habitat for numerous song birds and solitary 

nesting marsh birds such as the bitterns, rails, 

American coots (Fulica americana)? wood ducks 

(Aix sponsa), gallinules, limpkins (Aramus 

guarauna), sandhill cranes (Grus canadensis-), 

and marsh wrens. They also provided resting 

and feeding areas for migratory ducks, geese, 

and swans, and 20 species of shorebirds as 

they moved between breeding and wintering 

grounds (Errington 1966, Niering 1966). 

Since the 18th century man has ditched and 

attempted to drain wetlands, and since the 

1930's has succeeded in draining for agricultural 

use in the South alone some 20-30 million 

hectares (Stransky and Halls 1967). Thousands 

of wetland hectares have been inundated by 

reservoirs. Along with the drastic diaiinishing 

of Southern wetlands, populations of marsh 

birds declined as well (Bent 1926, Xeanley 1972). 

Some bird species whose ranges and occurrances 

were reported by Audubon (1944) and Bent (1926) 

are now Listed as extinct or endangered throughout much of their former range and other 

speciesf ranges have been drastically reduced 

(Meanley 1972; USDT 1977). 

Our present day Southern interior wetlands 

consist of isolated pockets of swaKps and 

river bottoms that could not be drajned for 

agriculture by ditching or stream channeiization. Channelization was even more detrimental 

to wetlands rhan mere ditching (tharton 1970) 

because the destruction and restructuring of a 

biotic community occurred when streams were 

straightened and cut clean of protective vegetation (Alexander 1963). If any thought to 

wildlife was given in prior channelization 

practices, it *;as to game fish popubations- No 

consideration to water quality nor non-game 

wildlife was given and as Russell (1966) 

pointed out, wjldlife is now suffering the consequences of this lack of thought. He suggests 

that laws be enacted requiring a 17-meter buffer 

zone between all streams and waterways and 

agricultural and forestry operations. This 

would provide for cleaner water, and more and 

better habitat for both fish and wildlife populations. 

Dredging of wateri.:ays have had an effect 

on declines in inland wading bird populations 

by the increase in turbidity of water (USAEDSL 

1975). 'Water turbidity and quality are key 

factors in declines, since wading birds are 

visual fish-eaters, and ~ust be able to see 

their prey. 

Another very important practice in the 

South is the heavy we of pesticides on agricultural crops. Residues from fields wash and 

leach into lakes, streams, and wetlands, and 

ccjntaminate these arcas. These areas have 

become sinks for these contaminants, unsafe for 

fishing, boating, and swimming; and in some 

areas these activities have been prohibited 

temporarily (the Mississippi Delta oxbow lakes 

are examples of this), The most visible 

evidence of problems with pesticide and fertilizer contamination is fish kills and depletion of game fish species. Less apparent but 

just as deadly is the biomagnification 

resulting from continued use by fish-eating 

birds of the contaminated fish sources. Numerous cases of poptif:3tion decline of bald eagles 

[iiaiiaeatus leucocephalus), ospreys (Pandion 

---- haliaettis), other raptors, and wading and sea 

birds have been noted by many authors due to 

eggshell thinning from coatahination which 

results in unsuccessful nesting attempts. Indeed, even though its use has been banned for 

several years, the continued spector of DDT/DDE 

contamination haunts our Southland and other 

heavily agricultural areas. 

Forest harvest practices in the past, 

although not having the wide-reaching effects 

of agronomic practices, have also played a role 

in wildlife population declines (Glawson 1975). 

Clear cutting, which allows greater erosion and 

stream pollution unless carefully managed, has 
contributed to the problem. Stream bank cutting and ditching to drain hardwood bottomlands and bald cypress (Taxodium distichum) 

stands for forestry equipment access have 

changed stream temperatures, ground water 

levels, sediment and chemical loads in streams 

(Clawson 1975). 

Urban and industrial development cannot 

escape blame in the decline in wadingfmarsh 

bird populations. As the human population 

has grown, pressures from industrial sites and 

their wastes, human recreation activities 

(boating, fishing, hunting, and even birdwatching), human housing needs, and other uses 

generally termed as "progressive" in our eyes, 

have all contributed to disruption of life 

cycles and destruction of habitat necessary 

for birds' survival. 

Table 1 

Wading bird species that use freshwater wetlands for nesting and/ or feeding and loafing, 

Colonial Nesters 

Great egret(Casmerodi2s alku~) 

Snowv . e~ret(Eeucophoyx - thula) -- - - - * -- ---- Great blue heron ("i_rLe_a- &rod_1.a_~_) 

Little blue heron(F1orida - --- caerulea) 

Green heron(Butorides virescenf3j 

Black-crowned nieht - heron(Nvcticorax nvcticorax) .-'-.-..----A ---- - 

Ye 11 ow-crown ed night her on (~~J~>~v-i.i_"_c_ea) 

Wood ibis (E";yct@ria age~i~anz) 

kkite-faced ibislCp1egadi.g chi)^) G~O s sy ib i s1 (PLe-gadis f_a?,c+p~~l.~sj 

Double-crested cormorant (~~l-~crocor&~ auritus) 

Anhinga (&h-inga anhinga) 

White ibis (Eudocimus aLbp-s) 

Ca t t l e egr e~(&b~l~u.s.s 2i.s)- 

HABITAT REQUIREMENTS 

Solitary Nesters 

Life requirements of the six major bird 

groups using southern wetlands are quite 

different (Robbins et al. 1966). These six 

groups are: 1) migrating and overwintering 

shorebirds; 2) migrating and overwintering 

waterfowl, including the resident wood ducks 

and hooded mergansers (Lophodytes cucullatus); 

3) the fish-eating raptors that generally 

overwinter, although some nesting still occurs; 

4) the wetland nesting and feeding passerines, 

woodpeckers, and belted kingfishers 

(Megaceryle alcyon) ; 5) the so1.i tary nesting 

rails, gallinules, coots, limpkins, sandhill 

cranes, and bitterns; and 6) the colonial 

nesting herons, egrets, ibises, and cormorants. 

For the purposes of this paper only Groups 5 

and 6 which.include 27 species (Table 1) will 

be considered and discussed, although in 

general any habitat preservation or development 

will help all wetlands users. 

King rail (Rallus elegans) 

Virginia railL (~il~s~~micola) - --- - 

Sora (Porzana carolxna) --..- --..-- Black rail(Lat_er-al-l.us jamaic-ensis) 

Yellow rail-oturnicops noveboracensis) 

Limp kin (Eamus- guarauna) 

Whooping crane! (- %e_r_i._afia) 

Sandhi11 cranelGrus - canadensis) -- - - -- -- -- American coo tl (~ulica amer-icana) 

Common gallinule(Gallinu1a - chloropus) ---- --...--- 

Pur p 1.e :a 11 inu le (~o~p_hhyrula milrtiii.C2) 

American bittern~iBotaurus lenti~inosus) -- - - -. - - - - -"-.- - - -. 

Least bit tern (Lxob-rychus exi.1.s) 

- 1/ Feeding/loafing use only 

2/ Nesting only---species feeds in upland - 

areas 

Colonial Nesters 

Nesting Requirements 

Colonial. nesting wading bird species 

generally require a tree-shrub nesting substrate, although in Texas they have been known 

to nest on the ground as well as in shrubs and 

trees (Chaney et al. 1977). All of the species 

listed on Table 1 will nest together in mixed 

colonies in varying percentages although some 

pure colonies of great blue herons (Ardea 

herodias) do occur in inland areas (Thompson 

1977). Chaney et al, (1977) noted as many as 

eight species nesting together. Meanley (1956 

and 1972) reported a colony of little blue 

herons (Florida caerulea), snowy egrets 

(Leucophoyx thula), great egrets (~asmerodius 

albus), green herons (Butorides virescens), --- 

Swan Lake, Arkansas. Gersbacher (1939) 

reported large numbers of great egrets, doublecrested cormorants (Phalacrocorax auritus), 

great blue herons, black-crowned night herons 

(Nycticorax nycticorax), and anhingas nesting 

together at Reelfoot Lake (colony now extinct; 

Gersbacher 1964). 

Nesting substrate in Southern freshwater 

wetlands generally can be expected to consist 

of bald cypress, tupelo gum (Nyssa aquatica) , swamp privet (Forestiera acuminata), black 

willow (SaLix nigra), button-bush 

(Cephalanthus occidentalis) and other Southern 

swamp shrubs and trees (Bent 1926; Meanley 

1972). Great blue herons have been knowi to 

nest in pecans (Carya illinoensis) in Texas 

(John Smith 1976, Texas Parks and Wildlife 

Department, personal comunication). The birds 

generally will build their nests at or near 

and anhlngas (Anhinga anhinga) nesting at the top of the canopy at heights ranging from 
1-30 meters, depending on the nesting substrate. 

They select secluded sites for their colonies 

that offer protection from predators and 

isolation from humans. Frequently they nest on 

islands, or the sites will have insular characteristics such as being surrounded by impenetrable marsh or thickets. They also usually nest 

near their feeding areas, but if hard pressed 

for nesting sites they will select sites several 

miles away, Ssharf (1976) reported a large 

colony of waders which nested on an isolated 

island in Lake Erie but that flew as far as 30 

kilometers away to feed. 

Nesting chronology varies with locality, 

but generally begins for all species by March 

and all young have usually fledged by September. Cattle egrets (Bubulcus ibis) are the 

latest nesters, will be the last species to 

enter a heronry, and have increased in population while other species declined. This may be 

attributed to the fact that they are wetlands 

nesters but upland feeders, and therefore do not 

suffer the limitations imposed by diminishing 

wetlands (Davis 1960). Great blue herons will 

nest in February in most localities. In south 

Florida, most species are late winter-early 

spring nesters, especially wood ibises 

(Mycteria americana) (Rushlan 1976; Browder 

1976). Roosting areas are usually in the same 

area as the nesting colony. 

Feeding Requirements 

All wading herons, egrets, and ibises feed 

almost solely on fish, crustaceans, amphibians, 

and insects (Martin et al.. 1951). These birds 

were much persecuted as being predators of 

game fish until research (Cottam and Uhler 

1945) proved that 75% of their diet consists of 

non-commercial fish, frogs, snakes, crayfish, 

mice, and. similar prey. Obviously, they are 

feeders in an aquatic environment, and any 

decrease in wetlands area decreases these 

species' feeding habitat proportionally. 

Solitary Nesters 

Nesting Requirements 

Rails, limpkins, bitterns, gallinules, 

coots, and sandhill cranes are all prone to nest 

in isolated pairs in tall marsh grasses, cattails latifolia), and sedges (Bent 1926). 

They build their nests in secluded spots above 

the water level by matting together the vegetation or by fastening the nest to the stems of 

vegetation. They will also nest on old stumps, 

in mats of vines, or low shrubs, They too will 

choose insular situations for nest sites, as 

this affords them protection from predation 

and disturbance, but they hide their nests carefully in comparison to the colony nesters. 

These species usually begin nesting irL 

March and all young fledge by August. These 

birds roost in the same habitat in which they 

nest: tall marsh grasses, cattails, sedges, 

and low shrubs. 

Feeding Requirexeats 

Feeding requirements are varied for this 

group of birds. Sandhill cranes usually are 

vegetarian, consuming marsh vegetation such as 

chuf a (aerus esculenrus) , bulrush 

spp.), waterlily ( 

wetland plant leaves, stems, tubers, and seeds. 

They do eat some insects, frogs, snakes, and 

toads (Walkinshaw 1545). 

Limpkins almost always only eat the soft 

bodies of snails, and rails are solely consumers of inseets and crustaceans (Martin et al, 

1951). Gallinules are opportunists and change 

with the season. In spring they consume 35% 

and in fall 83% plant foods (grasses, millet 

(Echinochloa spp.), and rice (Oryza sativa). 

They will also eat aquatic insects, mollusks, 

and other insects (Bent 1926), All species 

are directly dependent upon wetlands for their 

food sources. 

ILABITAT: WHAT CAN BE DONE 

Given the background of massive, universal impact on Southern wetlands and the wildlife that inhabits them, a very gloomy picture 

emerges. "Most land and water investments are 

terribly permanent. What is done cannot be 

undone by us or our children" (Clawson and Fox 

1961). The wetlands that have become agricultural lands, reservoirs, and urban sites in 

years past will undoubtedly remain as they are 

now. Even as most biologists realize the vital 

need to protect our remaining wetlands, 

pressures from both private and public sources 

to alter our wetlands are still felt. In 

Mississippi less than five percent of the productive hardwood bottomlands in the Delta area 

remains, yet private land owners still are 

draining and clearing as fast as permits are 

available. 

Section 404 regulations giving the U. S. 

Army Corps of Engineers biologists authority to 

determine wetlands areas before pennits will 

be issued for land alteration should slow 

down the destruction of more wetlands. New 

guidelines are being established, and research 

is under way at bES to determine indicator 

species and other identifiers of wetlands and 

transition zones that will be extrfsmely useful 

to field biologists responsible for permit 

determinations. 

Where does the present situation leave the 
wading bird populations so badly decimated by no accident or coincidence that the colonies and 

pesticides, habitat destruction, and human populations of herons and egrets decline in the 

encroachment? Remedies are not fast and clear- Mississippi River system from north to south 

cut. Realistically, the manager of a wetlands (Thompson 1977). Pesticides and sediment loads 

area must be prepared to accept the fact that in the river which increase as it flows southhe cannot expand the wetlands outside the land ward have taken a deadly toll on historic pophe can control (refuges, management areas, game ulations. 

farms, commercial forest lands). Therefore he 

will have to settle for limited results. But Finally and of equal if not greater importhe cumulative efforts of all managers could be tance, is the absolute necessity of providing 

a modest expansion of wetlands in the South protection in wetlands areas from humans and 

that would increase available habitat not only predators that would disturb a wading bird 

for the wading birds in question, but other colony. Signs prohibiting entry to colony 

marsh users such as the economically attractive areas, education of the public, fences, and 

waterfowl species. tough laws are required to ensure the protection these species must have to exist. ShootSeveral habitat development and manage- ing of nesting herons and egrets occurs for 

ment practices will need to come into use when sport and for malice, and must be controlled by 

consideration is given to providing freshwater law enforcement officials. 

habitat for wading birds. First, all existing 

wetlands areas should be protected and managed 

very carefully to ensure that their quality is SWY 

not decreased by pollutants (sediments, 

chemicals, pesticides, excess nutrients) from In summary, neither wetlands nor wading 

outside sources. This is a difficult assignment, bird populations will ever regain what has been 

since it would require enforcement of water lost to man. Only by preservation and managequality standards and education of surrounding ment of existing wetlands and as much expansion 

land owners as to proper conservation and as is possible of historic wetlands will wading 

farming practices to prevent erosion, over- birds survive and increase. Pesticides, excess 

fertilization and over-spraying of chemicals nutrients, and sedimentation have taken tolls 

and pesticides. in bird populations and disrupted their reproductive processes. Human disturbances have 

Second, permanent wetland areas should be caused tremendous upheavals in nesting colonies. 

created where none exists that meet the follow- Five practices are recommended for management 

ing requirements: 1) varying water depths with of wading birds in freshwater wetland habitats: 

large areas of shallow marsh, 2) good water 

quality, and 3) year-round protection, especial- 1) All existing wetlands should be 

ly in spring and summer. Temporary greentree preserved and managed 

reservoirs and flooded fields are an established 2) New permanent wetland areas should be 

practice for wintering waterfowl. Something of created 

this nature on a permanent basis is needed for 3) Expansion of some temporary wetlands 

wading birds that will provide a habitat for the into permanent areas on refuges and management 

prey of wading birds. The key here is to areas should be done as rapidly as possible 

provide more feeding habitat, as nesting habitat 4) High water quality should be maintained 

has usually not been found to be a population- in all wetlands areas to ensure feeding habitat 

limiting factor. A temporary water-retaining for fish-eating birds 

structure for waterfowl only helps wading 5) A11 areas must be protected from humans 

birds during the months of actual flooding and predators to be of real value to wading 

(winter). The rest of the year, and especially birds year-round, but especially during the 

during the critical nesting season when quality nesting season (February-September). 

foods are needed in abundance, flooded habitat is 

simply not available to wading birds in a 

management system for waterfowl. LITERATURE CITED 

Third, some areas on all refuges and manage- Alexander, H. E. 

ment areas should be converted to permanent 1963. Fish and wildlife vs. water manageshallow water ponds and marshes for year-round ment - some basic considerations. In 

use by waders as feeding areas. Deeper water Proc. 17th Southeastern Game and ~ix Comm. 

is needed for cormorants' fishing. Conf. pp. 41-47. 

Audubon, J. J. 

Fourth, a very important requirement for 1844. The Birds of America, Vol VI. Reprinted 

all species is clean, clear water so that the 1967 Dover Publ., New York. 457 pp. 

birds can see their prey. Rivers, lakes, streams Bent, A. C. 

clouded with sediment and contaminated with 1926. Life Histories of North America Marsh 

chemicals are useless to visual feeders. It is Birds. Reprinted 1963 Dover Publ., 
New York. 392 pp, 

Browder, 3. A. 

Martin, A. C., H. S. Zim, and A. L. Nelson. 

1951. American Wildlife and Plants: A Guide 

1976. Water, wetlands, and wood storks in to Wildlife Food Habits. Reprinted 1961 

southwest Florida. Unpublished PhD Dover Publ., New Uork. 500 pp. 

dissertation, Univ. of Fla. 417 pp. 

Buckley, P. A., and F. G. Buckley. 

1976. Guidelines for the protection and 

management of colonially nesting waterbirds. 

North Atlantic Regional Office, National 

Park Service, Boston, Mass. 

Chaney, A. H., B. R. Chapman, J. P. brges, D. A. 

Nelson, R. R. Schmidt, and L. C. Thebeau. 

1977. The Use of Dredged Material Islands by 

Colonial Seabirds and Wading Birds in 

Heanley, B. 

1956. Nesting of the water turkey in Eastern 

Arkansas. Milson Bulletin 60: 81-88. 

Meanley, B. 

1972. Swamps, River Bottoms, and Canebrakes, 

Barre Publ., MA. 142 pp. 

Mills, H. R. 

1934. Report on the Tampa Bay Rookeries. Fla. 

Naturalist 8:l-4. 

Niering, W. A. - Texas. U. S. Army Engineer Waterways Exper- 1966. The Life of the Marsh - the North 

iment Station Technical Report TR-78- In Wetlands, NcGraw-Hill, New York. 

press. Portnoy, J. 

Clawson, M. 1977. Bird colonies of the Northern Gulf of 

1975. Forests for Whom and for What? John Mexico. & Proc.2nd Colonial Waterbird Conf. 

Hopkins Univ. Pres. 175 pp. In press. 

Clawson, M., and I. Fox. Robbins, C. S., B. Bruun, H. S. Zim, and A. 

1961. Your investments in land and water. Singer. 

American Forests, Part 1: 67(1) Jan 1961. 1966. Birds of North America. Western Publ. 

pp 4-11, 53-56. Co., New York. 340 pp. 

Cottam, C. and F. M. Uhler. 

1945. U. S. Fish and Wildlife Service Leaf272. 16 pp. 

Custer, T. 

1975. Survey of East Coast heronries. 

Putuxent Research Center, U. S. Fish and 

Wildlife Service. Unpublished data. 

Davis, D. E. 

1960. The spread of the cattle egret in the 

United States. AUK 77(4): 421-424. 

Dunstan, F. and S. Dunstan. 

1977. Tampa Bay Sanctuary bird nesting data 

and island vegetation. Appendix & 

Colonial Bird Use and Vegetation Succession 

of Dredged Material Islands in Florida. U. 

S. Army Engineer Waterways Experiment 

Station Technical Report TR-78- . Vicksburg, 

Ms. In press. 

Errington, P. L. 

1966. Of Men and Marshes. Macmillan Publ. 

New York. 

Gersbacher, E. 0. 

Russell, D. M. 

1966. A survey of streambank wildlife habitat 

- In Proc. 20th Southeastern Game and Fish 

Comm. Conf. pp 37-41. 

Ryder, R. 

1977. Gulls in Colorado: Their Distribution, 

Status, and Movement. In Proc. 2nd Colonial 

Waterbird Conf. In press. 

Scharf, W. 

1976. Nesting and Migration Areas of Birds in 

the U. S. Great Lakes. Interim Report. 

USFWS/OBS 77-2. In press. 

Soots, R. F., Jr, and J. F. Parnell. 

1975. Ecological succession of breeding birds 

in relation to plant succession on dredge 

islands in North Carolina estuaries. Sea 

Grant UNC-SG-75-27. North Carolina State 

Univ., Raleigh, NC. 

Stransky, J. J. and L. K. Halls. 

1967. Woodland management trends that affect 

game in coastal plain forest types. In Proc. 

21st Southeastern Game and Fish Comm. Conf. 

1939. The heronries at Reelfoot Lake. Report pp 104-108. 

of the Reelfoot Biological Station, Vol. 111,Thompson, D. H. 

pp 162-180. Tenn. Acad. Sci., Nashville. 1977, An aerial survey of waterbird colonies 

Gersbacher, E. 0. along the upper Mississippi River and their 

1964. Heronries of Reelfoot Lake - 25 years relationship to dredged material deposits. 

later. J. Tenn. Acad. Sci. 39(1): 15-16. U. S. Amy Engineer Waterways Experiment 

Goodwin, R. H. and W. A. Niering . Station TR-78- . In press. 

1971. Inland Wetlands: their ecological U. S. Amy Engineer District, St. Louis 

role and environmental status. IUCN Marsh (USAEDSL). 

Conference. 1975. Environmental Impact Statement for 

Kushlan, J. A. Operation and Plaintenance of Pools 24, 25, 

1976. Feeding behavior of North American and 26, Mississippi and Illinois Rivers. 

herons. Auk 93(lj: 85-94. U. S. Dept. of Interior (USDI). 

Landin, M. C. and R. F. Soots, Jr. 1977. Federal Endangered Species List. USFWS 

1977. Colonial bird use of dredged material Office of Endangered Species, Washington, 

islands: a national perspective. In Proc. D. C. 

2nd Colonial Waterbird Conf. , ~ekalc Walkinshaw, L. W. 

Illinois. In press. 1949. The Sandhill Cranes. Cranbrook Inst. 
of Sci. Bloomfield Hills, Nich. 202 pp. 

Williams, L. W. Jr. and L. Martin. 

1968. Nesting status of the Brown Pelican in 

Florida in 1968. Q. 3. Fla. Acad. 31(2): 

130-140. 
Census Techniques for Forest Birds 

Chandler S, Robbins ;l_/ 

Abstract.--The spot-mapping method is generally acknowledged to be the most 

dependable of the several census methods for forest birds in the breeding 

season. Transects and point counts, especially when well standardized and 

corrected for biases, may be preferable if large areas nust be sampled in a 

short period of time. 

OPTIPLAL SEASOUS FOR CEfr'SUSIliG 

With the increasing emphasis on nongame 

birds as an important natural resource, forest 

managers are looking for efficient ways to 

document their populations, for both research 

and educational purposes. This paper will 

summarize and comment upon the principal 

techniques that have been used successfully at 

various seasons of the year. 

CHOICE OF TECHNIOIJCS 

Unfortunately, there is no quick and easy 

way to measure bird populations in forest 

habitats. Indices that can be used for 

comparing one plot with another are relatively 

easy to obtain, but it is seldom practical to 

attempt an actual head count on even a small 

sample plot of 6 to 10 hectares. Almost any 

attempt to obtain a population estimate must 

be a compromise between the degree of accuracy 

sought and the amount of time and trained 

personnel available. 

The average adult songbird has only a 40% 

to hOX probability of being alive one year 

later. For young birds, the likelihood is 

considerably less. Thus, bird populations are 

conti nually changing through production of 

young, death of young and adults, local 

wandering in and out of study plots, and for 

most species, migration. Mortality of young 

birds is highest in their first one or two 

weeks af ter fledging. I!ortality of adult 

birds of most species is highest during 

migration, or periods of severe weather, which 

are most likely to occur in midwinter. 

- 1," tiildlife Biologist (Pesearch), lligratory 

Bird and Habitat Research Laboratory, U. S. 

Fish & lTildlife Service, Laurel, MD 20811 

Bird census work can be done with greatest accuracy during the peak of the breeding 

season, which for most species is in ?lay and 

early June in the Southeast. At this time, 

most male birds are defending territory and 

are strongly attached to a very small area of 

a specific habitat for four or more weeks. 

Curing the peak of the nesting season nost 

male birds are in song every day, at least 

during early morning hours, and are much more 

easily detected than later in the summer. In 

winter and during the migration seasons, birds 

are much more nobile and less attached to a 

specific habitat type. 

DOCUtfklPiTAP, Y STUDIES 

Any census work undertaken should be 

initiated with one or more particular 

objectives in mind. If one wishes only to 

document the species that are using a forest, 

help can frequently be enlisted from local 

experienced aiateurs. 

Since I work primarily with anateur ornithologists on cooperative programs to nonitor 

populations, I naturally think of the vast 

resource of qualified help that is available 

to assist with bird population studies. 

Tor example, nearly all of the national 

wildlife refuges have lists of birds of their 

area that are available for free distribution 

to visitors. Some of these lists raere 

compiled entirely by amateur volunteers, and 

in almost all cases amateurs contributed many 

of the records. I!ost of the national parks 

also have publications on their wildlife 

resources, Comparatively few national, state, 

or other forests, however, have made lists of 

birds and other fauna available to the public. 

I believe that provision of such lists is one 

of the first steps toward arousing public 
- - - )&dl- 

," 

0' STARLINGS 

WOODPECKERS 

CREEPER + NUTHATCH 

TITS 

THRUSHES 

FINCHES c BWTINGS 

0 5 o loo 150 200 years 

Figure 1.--Changes in consuming biomass as represented by 

the principal bird families during a 200-year succession 

in an oak forest in France. From Ferry and Frochot (1970). 

interest in the biological resources of a 

forest. Volunteer cooperators should be able 

to prepare such lists, and furthermore, assist 

Later with quantitative studies of bird 

populations. 

Parts of many of the national and state 

forests are included within 15-mile diameter 

Christmas Bird Count circles. An easy way to 

enlist volunteers to assist in the preparation 

of a List of species for a specified forest 

would be to contact the Christmas Count 

compiler (whose name and address are always 

given in the published report in American 

Birds) and get from him the name of the person 

or persons responsible for covering the 

forest. By asking this observer to keep a 

separate record of birds seen in the forest, 

one can not only start to build up a file of 

information on the winter avifauna of the 

forest, but one can also generate the interest 

necessary for continued assistance through all 

seasons of the year, If help is needed in 

documenting presence of endangered species, 

this also can often be done by enticing 

qualified amateurs to join in the search. 

Hager 1960, Michael and Thornburgh 1971, 

Conner et al. 1975, Webb et al. 1977, 

Schweitzer 1978). Such studies can also be 

used to document population changes during 

successional stages (fig. 1) or during 

recovery from fire, surface mining, or other 

ecological changes (Johnston and Odum 1956, 

Ferry and Frochot 1970, Hamilton and Noble 

1975, Shugart and James 1973, Shugart et al. 

1975). Comparative studies can also be used 

to assist management decisions. For example, 

one may wish to choose among several areas for 

a particular management program, or even for 

preservation of a unique ecosystem such as to 

provide habitat for a particular endangered or 

threatened species. 

Williamson (1970), for example, has used 

spot-mapping censuses to show that density and 

diversity of bird-life in coniferous plantations can be increased by providing a fringe 

of deciduous trees or leaving small "island 

refuges" of scrub or deciduous trees. Such a 

practice might even provide additional 

benefits by reducing insect damage. 

EmEDING SEASON TECHNIQUES 

COMPARATIVE STUDIES 

Spot-mapping Census 

For comparing bird populations of two or 

more sites, we must turn to methods that will 

yield numerical estimates sf bird population, 

or at least index values, Such studies would 

include the need to document populations 

before and after some particular management 

program, timber harvest procedure, fire, 

pesticide treatment or other event that might 

influence bird populations (Kendeigh 1947, 

The spot-mapping technique, also called 

the plot census or, simply, mapping census, 

was first employed in North America by 

Williams (1936) and in Sweden by Enemar 

(1959). Basically, this technique consists of 

making 8 or 10 census trips through a plot of 

known size, and preferably of uniform habitat, 

that has been surveyed and mapped with a grid 
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habitat types or different regions are 

compared a check should be carried out on a 

sample of maps to see if there are any 

differences in the evaluation procedures 

applied. 

Nilsson (l977), in an evaluation of the 

mapping method, believed that more than 10 

visits, and perhaps as many as 20, may be 

requj-ed for accurate cecsusing ef certain 

difficult species, He suggested that the 

number of visits might be reduced if more time 

were spent on each visit, 

Berthold (1976) published a comprehensive 

critique of bird census methods with emphasis 

on the mapping method. Ee concluded that 

there are almost no methodologically perfect 

tests of census methods; that errors of 50% or 

more are cormon; and that although many errors 

and sources of errors have been recognized in 

the literature, they have not sufficiently 

been taken into consideration. Re recommended 

abandoning relative census methods in favor of 

more absolute methods, and he proposed using 

nest finding and banding to supplement 

mapping. He stated that census methods should 

be more standardized and that calculations or 

jusrified estimates of errors should be 

included in published results. A- J. Erskine, 

who has translated Berthold's critique into 

English for the Canadian MildLiie Service 

(unpublished manuscript), points out that 

"Berthold is not himself a worker in bird 

census studies but rather an environmental 

physiologist accustomed ro the careful 

regulation of variables often possible in 

laboratory studies. Ilany of the criticisms he 

advances are long familiar to census workers, 

whose experience would have prevented some of 

the sweeping generalizations in his review." 

Berthold does include an excellent bibliography, especially of German, English, 

and Scandinavian titles, 

The mapping method was recently criticized by Best (1975) as not yielding results 

that can be interpreted consistently by 

different experienced observers; but this 

criticism was unfair because the author 

apparently failed to follow standard procedures and neglected to obtain data on 

simultaneous registrations of the single 

species considered--data that are essential to 

proper interpretation of the results. 

To fairly test reliability, different 

observers must do the field work as well as 

deternine the number of territories on each 

map. This was done in a mature floodplain 

forest plot at the Patuxent Research Ref~ge in 

Pkryland by Robbins and Bridge. They conducted 

independent censuses of 3 visits each in a 40 

ha plot from 15 Pfy to 3 Sune 1962. One 

observer censused From north-south trails 

through the plot while the other used eastwest trails. After making independent 

estimates of the breeding population, the two 

observers combined their maps and made a 

revised estimate based on all 16 visits. With 

8 visits the observers had detected 89% and 

92% of the birds that were detected on 16 

visits. 

Diehl (19741, who made 27 and 21 visits, 

respectively, to two grassland plots totaling 

43.5 ha found that between 32% and 44% of the 

pairs present were detected on a single visit, 

and 952 to 98% on one or more of 20 visits, 

However, a great many of these birds were 

detected on only one or two visits and would 

not have been recognized as distinct pairs; 

thus while nearly all of the pairs had been 

observed and recorded, the population 

estimates from 10 visits would have been only 

53% to 66% of the number of pairs present. 

Other authors (Davis 1965, Jones 1974, 

Erskine 1974) have discussed problems in using 

the spot-mapping technique for certain species 

that are difficult to census, such as those 

that do not sing regularly, are not territorial, or range over areas much larger than the 

size of most census plots. Nevertheless, 

spot-mapping is still the most generally 

accepted method and the one most frequently 

used to calibrate the results of less 

time-consuming, but relatively less accurate 

methods. 

Census Summaries 

Three catalogs (Erskine 1971, i972, 1976) 

have summarized the results of 228 Breeding 

Bird Censuses that have been conducted in 

Canada. Censuses that have been published 

from 1337 through 1977 in American Birds have 

been put on magnetic tape at the ilfigratory 

Bird and Habitat Research Laboratory where 

they provide a valuable comparative resource 

that may be accessed either by hahicat, by 

bird species, or by a number of the other 

variables that are included in the computer 

record. This file presently contains 

information on 1,301 plots, 

Transects 

The transect method involves counting 

birds on one or both sides of a line through 

one or more habitats; in most instances either 

the width of the transect is defined or the 

distance to each bird encountered is estimated. The transect method was first used 

extensively in the United States in 1906-09 by 

Forbes and Gross (Graber and Graber 1963) and 

in Finland in 1941-56 by MerikaLLio (1958). 

In both instances, the transect results were 

used to estimate total populations by habitat 

for an entire state or nation, The Forbes and 
Gross study was later repeated by Graber and 

Graber (1963) to show bird population changes 

over a 50-year period. 

One advantage of the transect method is 

that it may be used throughout the year, but 

the results are less accurate outside the 

breeding season. Another advantage is that a 

relatively large area can be sampled in a 

short time. Flack (1976), for example, used 

150-foot-wide transects to compare breeding 

bird populations in 41 aspen forests in 9 

western states and provinces, 1966-69. 

The chief disadvantage of the method is 

that a single coverage of a transect does not 

permit a good estimate of the number of birds 

missed. Anderson and Pospahala (19701, using 

data from 1600 miles of transects, generated a 

curvilinear (quadratic) equation to show the 

fraction of waterfowl nests missed at various 

distances from the center line of the 

transect; but they pointed out that to 

adequately correct for the number of fixed 

objects missed one needs a large sample and 

one must also make the assumption that all of 

the objects closest to the center of the 

transect are detected. 

Emlen (1971)also has considered how the 

Figure 3.--Schematic model showing birds 

detected (circled dots) at various distances 

from the transect (heavy line). From Einlen 

(1971). 

error inherent in the transect count may be 

minimized by first estimating the lateral 

distance to each bird encountered (fig. 3), 

and then deriving a coefficient of detectability. He assumes that no bird close to the 

observer goes undetected. In actual practice, 

the number of birds within a few meters of the 

transect line that are undetected may be quite 

large (Jsrvinen and ~Xisgnen L475), especially 

in a mature forest habitat. Even during the 

height of the breeding season there is an 

enormous difference in singing behavior and 

conspicuousness among the various species. k 

noisy, active species such as the Tufted 

Titmouse may be recorded on 68% of the visits 

if within 50 meters of the observer, whereas 

species such as the Ruby-throated Hummingbird, 

Worm-eating Warbler, and even the American 

Redstart may be recorded only 36% to 39% of 

the time (Stewart et al. 1952, pp. 269-270). 

Emlen (1977) estimated the number of 

unrecorded males of common species by running 

each transect five times, plotting all singing 

birds on maps, outlining the territory of 

each, and determining what European workers 

call the "effectivity" of a single trip for 

each species. He then used the computed 

effectivity for correcting his breeding season 

transect results. 

The transect method is quite effective 

for comparing the abundance of a given species 

among two or more plots of similar habitat. 

Also, unless visibility is strongly influenced 

by the structure of the habitat, the transect 

method may be used to compare abundance of a 

given species from one habitat to another. It 

is not, however, a desirable method for 

comparing abundance of two species that may 

not be equally conspicuous, unless appropriate 

corrections are made, species by species. 

These corrections can be made by taking a 

series of transect counts through plots where 

the population has been estimated by other 

methods (Ferry and Frochot 1970), Enemar and 

Sjb'strand 1970). 

Although most transect workers record 

birds per kilometer (or per mile) or per 

square kilometer (or per 100 acres), a few 

have preferred to use units of time such as 

birds per 10 hours (Colquhoun 1940). 

Transects are especially effective along 

hedgerows and wood margins where it may seem 

impractical to establish mapping plots or make 

point counts. Johnston (1947) did, however, 

use spot-mapping in two isolated woodlots to 

compare distribution of forest-edge and 

forest-interior species. 

The IPA or Point Count Method 

The IPA (Indices Ponctuels dtAbondance) 
method was developed by Ferry and Frochot 

(1970) as a means of obtaining indices of 

abundance for comparing bird populations of 

different habitats (or of the same habitat in 

different locations) during the breeding 

season. 

The IPA counts by the French ornithologists consist of the establishment of a 

network of points regularly distributed 

through the habitat to be studied. The 

observer then stands at each designated spot 

for 20 minutes in the early morning in good 

weather and notes all birds heard and seen. 

Each spot is censused twice in the breeding 

season. The higher of the two counts of pair 

numbers is used as an index of abundance for 

each species. Each singing male, occupied 

nest or family of birds out of the nest counts 

as one pair, while a bird merely seen or heard 

calling counts as half a pair. The efficiency 

of a 20-minute stop seems satisfactory to the 

French investigators because during the last 5 

minutes only 3% more species and 9% more 

individuals were recorded in forest habitats. 

Ferry (1974) quotes Schwartz (1963, p. 

139) as stating that with a sample of 30 or 

more the mean may be compared with another 

number, whatever the type of distribution. 

Thus, it is possible to calculate whether the 

mean IPA of a species is statistically diff erent from zero, and so have an objective 

way of eliminating species whose occurrence in 

the habitat is due to chance or whose presence 

is unimportant. (In actual practice, of 

course, some of the scarcer species may be the 

ones most in need of gttention from forest 

managers.) Ferry (1974) has determined which 

species have statistically significant 

population differences in two habitats as 

indicated by the IPA method. He has then 

computed a percentage of difference as a final 

comparison of the two plots. In this way, 

numerical similarity indices could be computed 

among an entire matrix of different plots with 

a minimum of field work. Ferry also points 

out that by conducting IPA counts within a 

mapping census plot, one can determine the 

effectivity of the IPA method, species by 

species, and thus obtain correction factors to 

convert indices to population estimates. 

In Denmark, Jbrgensen (1974) conducted 81 

IPA censuses on 8 mornings from mid-May to 

mid-June. The 13 112 hours of effective field 

work was about 50% less than would have been 

needed for covering one census plot by the 

mapping method. Jbrgensen compared the density of each species among different habitats, 

- 21 In preparation 

using the Mann-Whitney U-test. Be concluded 

that the IPA method was well suited to a study 

of forest succession, in which it is desired 

to make statistical comparisons. He 

summarized habitat utilization (based on 15 to 

18 counts in each habitat) in terms of a list 

of dominant species, each comprising 5% or 

more of the registrations, and sub-dominants 

(2% to 5%). Then, using only the dominant 

species, he computed similarity indices among 

the various habitats using the formula 

s=2c/(a+b) %here s is the index, a and b are 

the numbers of species in each sample, and c 

tae number of species comon to the two 

samples. 

In the United States, ehe IPA method has 

been further refined by Whitcomb and Robbins 

- 2/ who make three 20-minute counts (each 

composed of four 5-minute seg~~.ect E) at eat:? 

po:nt. Tho three saw-les are taken at different times in the nesting season (generally 

early, middle, and late June) and at three 

different periods in the early morning hours 

in order to maximize the likelihood of 

recording all species present. 

Density-Frequency Relationship 

Blondel (1975) has introduced a further 

modification of the IPA method (Echantillonnage Frequentiei Progressif: EFP), The EFP 

method uses the presence or absence of a 

species on each of the 20-minute LPA counts to 

determine frequency of that species in each 

plot (fig. 4). Comparison of the IPA and the 

EFP figures allows one to determine for each 

species the relationship between its density 

and its frequency. The frequency of a species 

is shown to be closely correlated with the 

logarithm of its density (fig, 5); the lower 

the frequency the better the correlation. 

"Thus, frequencies of occurrence can be used 

as an objective measure of the number of 

individuals included in the community," 

Rotenberry and Wiens (1976) found a similar 

correlation between density and frequency 

using roadside transect (BBS) data. 

Blondel claims that the EFP method, which 

is highly standardized, is very useful for a 

rigorous statistical interpretation of data. 

He used the EFP method to calculate ecological 

profifes and niche breadth for each species. 

Be analyzed the structure of bird cornunities 

according to the structure of the vegetation. 

For each comunity, he determined the species 

richness, the species diversity index (Hf), 

the equitability (J'), and the level of fit to 

Galton's log-normal model. He also discussed 

the influence of reforestation on bird comunities. "In many instances, conifer 

plantations, especially Cedar (species not 

stated), seem successful in the rebuilding of 

comunities." Blondel concludes that the 
Parus ater sin. After entering a woodland he walked 

about50 malong a transect line. At this 

point he stopped for 5 minutes and counted all 

birds seen andlor heard ahead of him. Ne then 

walked ahead slowly for 5 minutes, averaging 

150-175 m. He repeated this procedure until 

he had 5 sample 10-minute counts from each 

forest interior. Two early morning visits 

were made to each woodlot and the highest 

count for each species was used. These counts 

detected 762, 78%, and 70%, as many pairs as 

were found by spot-mapping censuses in three 

of the same woodlands. Palmgren (1930) and =< 50i-pi ~<CO ICOO~ OW 40r-, ,*4~~,, Kendeigh (1944) found 81% and 632 of their 

A i UCI- birds in spot-mapping censuses were detected 

m3>75 , > > < / 0 

On the first two visits. 

L 

i re~be~cr 109 

Parus major 17 '..z:.." [TI "::;::: 

Echsllc , , , o i 21rm y = 0.0163~ - 0.68 

Figure 4,--EFP maps showing distribution of 

Coal Tit (above) and Great Tit with relation 

to elevation. Frequency, as shown by size 

of the dots in the legend, is based on an 

average of about four 20-minute IPA counts in 

each of the small rectangles. From Blondel 

(1975). 

standardized and time-saving EFP method "seems 

very well adapted to solve problems of 

theoretical and applied ecology at the 20 40 60 80 100% 

cornunity level, and can be used fruitfully 

for environmental monitoring." 

Comparison with spot-mapping 

In comparing point counts (IPA) with 

mapping census in ~iakowieia Forest in Poland, 

Tomia2ojc et al. (1978) found that point 

counts overestimate the population when the 

density is low and underestimate when density 

is high, IPA counts also require better observers and encounter more problems separating 

migrants or other non-breeding birds from 

breeding individuals than do mapping censuses. 

Combining transects and point counts 

Bond (1957) used a method that was 

essentially a cornbination of the transect and 

point count methods to compare bird populations in 64 upland hardwood stands in Wisconfrequency 

Figure 5.--Relation between frequency of 

detection and logarithm of numbers of individuals detected for 239 pairs of 57 

species. Confidence interval, p =.05. From 

Blondel (1975). 

Breeding Bird Survey 

The North American Breeding Bird Survey 

(BBS) was developed by the U. S. Fish and 

Wildlife Service to monitor bird population 

changes in North America over a period of 

years (Robbins and Van Velzen 1967, 1969, 1974). 

Each survey route is a series of 50 3-minute 

point counts at 112-mile intervals along a 24 

1/2-mile roadside transect that was selected 

by a random procedure. Coverage extends from 

one-half hour before sunrise to about 4 hours 

after sunrise and thus embraces the period of 
greatest bird activity (fig. 6). At each of 

the 50 stops, all birds heard and all birds 

seen within one-quarter mile of the counting 

position are tallied. The SBS, which now 

embraces the populated areas of Canada arid ail 

of the United States except Hawaif, provides 

an annual sample from 1700 or more roadside 

transects. The results are widely used for 

documentary and research purposes, and are 

also available for comparison with intensive 

local population studies, such as Miniroutes 

that use the same method. 

V) 

U, 40 The BBS results are used primarily for m statistical analysis of population changes 

over the years (fig.7) and for mapping of 

30 relative breeding densities throughout the 

North American range of a species (fig. 8). A 

ten-year summary of the BBS results is in 2 0 preparation. 

10 BBS Miniroutes 

For intensive local studies, BBS routes 

I ll.lI,L 

- 1 o +I +2 -3 -4 .: can be laid out in a non-random way, so that Time with reiat~on to Iocni stinrise all or most secondary roads within the area of 

Figure 6.--Hourly variation in bird counts. interest are included in the sample (fig. 9). 

The outer lines represent 95% confidence The term "Miniroute" results from a 25-stop 

limits based on 4 days in June 1969. From instead of a 50-stop format. By using a 

Robbins and Van Velzen (1970). shorter route, observers were able to complete 

Figure 7.--Population trends in the Starling in the western, 

central, and eastern regions of North America. Data from 

Breeding Bird Survey. 
Figure 8.--Relative abundance of the Red~tailed Hawk in 

the 1968-70 breeding seasons. Data from Breeding Bird 

Survey. 

Figure 9.--Map of Howard County, Maryland, 

showing locations of the mid-points of each 

5-stop section of the network of Miniroutes. 

their coverage before working hours in the 

morning. By covering each route twice (once 

in each direction) and combining the results 

of the two counts, most of the difference in 

activity resulting from time of day could be 

eliminated (fig. 10). Bystrak and others 

(Klimkiewicz and Solem 1974) used Miniroutes 

to map relative abundance of breeding birds 

throughout two Maryland counties (fig. 11) as 

part of a Breeding Bird Atlas program for 

these counties. Although the Miniroute 

technique was designed for roadside use, it 

could be applied with slight modifications to 

-.5 SR +. 5 +1 +1.5 

time 

Figure 10.--Mean number of Red-eyed Vireos 

recorded per half hour on Howard County 

Miniroutes, 1973. The top line is the sum 

of the two coverages of each route. Time in 

hours is given with relation to local sunrise 

(SR) . 

coverage of forested areas on horseback or by 

off-road vehicles, making it possible to map 

distribution of breeding birds over a wide 

area with a minimum of expenditure of time. 

Differences in bird populations could then be 

correlated with differences in vegetation 

obtained from aerial surveys or by ground 
Figure 11.--Relative abundance of breeding Red-winged 

Blackbirds in Howard County, Maryland, plotted from the 

summation of two coverages of each of the five-stop 

segments shown in figure 9. 

survey methods. 

Breeding Bird Atlas 

Breeding Bird Atlasing has become a popular pastime among bird observers in Europe 

during the past decade. Atlases showing 

breeding distribution maps for each species 

have recently been published for the British 

Isles (fig. 12), France and Denmark; and 

similar atlases are in progress in several 

other European nations (Belgium, Czechoslovakia, Finland, Federal Republic of 

Germany, Italy, Netherlands, Poland, Sweden, 

Switzerland). A more comprehensive mapping 

program involving all of Europe is planned 

for 1985-1988 using 50-km grids. 

The initial purpose of preparing a 

Breeding Bird Atlas was to correlate bird 

distribution with that of plants as shown in 

the Atlas of British Flora (Perring and 

Walters 1962). In a government-sponsored 

program carried out through the British Trust 

for Ornithology and the Irish Wildbird 

Conservancy, observers visited every one of 

the 3,862 10-kilometer squares (100 square 

kilometers each) of land area throughout the 

British Isles during a 5-year period and 

reported presence or absence of each bird 

species (Sharrock 1976). Twelve transparent 

overlays, that must be ordered separately from 

the book, facilitate correlation of bird 

distribution with selected environmental 

factors such as July temperature, elevation, 

and distribution of moorland, sessile oakwoods 

(fig. 13), and standing fresh water. 

In other countries, the sampling blocks 

have been of different sizes, depending upon 

the size of the total area to be sampled and 

the standard maps available. In France the 

sampling unit was 20 by 27 km (Yeatman 1976) 

while in Denmark it was a 5-km square (Dybbro 

1976). In several countries (Belgium, 

Czechoslovakia, Poland) the method has been 

modified to include some indication of abundance rather than merely noting presence 

or absence. 

No large-scale atlas has been attempted 

in the United States because the BBS provides 

an annual sample of changing abundance of each 

species and also gives a density of coverage 

roughly comparable with the projected European 

atlas of the 1980's. 

Nevertheless, atlas studies have been 

initiated in several states (Illinois, Maryland, Massachusetts, Vermont, and parts of 

California and Michigan), generally using 

grids smaller than the 10-km British grid. 

These American atlas studies will provide a 

source of information on presence and absence 

of the various species in many forested areas. 

The majority of atlas studies in the 

United States utilize a 5-km grid (6 blocks 
Figure 12.--Breeding distribution of the 

Wood Warbler in the British Isles. Size of 

dots indicates the three atlas categories of 

possible, probable, and confirmed (largest 

dot) breeding, Map from Sharrock (1976). 

per 7 112 minute topographic map), but the 

Maryland Ornithological Society has changed 

from 5 kn to 2 l/2 km '"quarter blocks" (about 

600 hectares or 1500 acres). The quarter 

blocks not only make it possible to pinpoint 

the location of rare species and others of 

special interest, but they also are much 

better for outlining areas where a particular 

species is not present (fig* 14) (Klimkiewicz 

and Robbins 19741, This feature takes on 

special significance in areas where comercial 

or residential cormunities are expanding or 

where habitats are being lost through various 

types of development. And in areas where 

large forests are being destroyed by changes 

in land use, quarter-block atlas data have 

been of immense value in showing to what 

degree various breeding species disappear when 

forested areas become fragmented into smaller 

tracts (fig. 15). 

In situations where insufficient 

personnel is available ta visit all atlas 

blocks, intensive coverage of a random sample 

Figure 13.--Transparent overlay from Sharrock (1976) showing distribution of Sessile 

Oak Woodlands, Compare with figure 12. 

Figure 14,--Breeding distribution of Pileated Woodpecker in two Ylryland counties 

in the Baltimore-Washington area showing the 

great improvemene in precision when 5-km 

atlas blccks (Montgomery County) are 

replaced by 2 li2-km quarter blocks (Howard 

County), The ehree atlas categories are 

indicated by darkness of shading. 
Figure 15,---Atlas quarter-blocks in Howard County, Maryland, 

slzowing forest fragments from which breeding bird species 

that require Large tracrs of forest interior are lacking. 

The species missing from the fragments still nest in the 

extensive wondLdnds along the Patuxent and Middle 

Pntuxent stream valleys at the left and right edges of 

the map: Black-and-white, Worn-eating, Northern Farula, 

Cerulean, Kentt~cky , and Ho~ded Warblers, and others. 

Figure IS,--Size comparison of Wood Thrush singing 

territories at Patuxeat Wildlife Research Center determined from spot-mapping (shaded ovals), and home ranges 

of some of the same males determined by banding. Total 

area of this map section is 22 ha, 

of small blocks is greatly to be preferred The atlas technique yields high returns 

over casual coverage of much larger blccks, in the first day of field work in a given 

block. In 12 10-km blocks, each with 78 to 90 
breeding species, an average of 32 species 

were detected in the first 16-hour day 

(Sharrock 1974); 40 of these species had been 

found in the first hour and 60 by the end of 8 

hours. It is the added effort of searching 

for the important hard-to-find species and the 

accumulation of nesting evidence that is very 

time-consuming. Recent recognition that rare 

and/or disappearing species are most likely to 

be present in the largest forest tracts within 

a given grid should greatly reduce the effort 

required to locate such species. 

Banding 

Several investigators in the United 

States, Sweden, and France have used the 

marking and recapture of birds as a means of 

studying the effectiveness of other census 

methods (Stamm et &. 1960, Svensson pers. 

comm., Frochot 1977). 

Banding in itself is neither an efficient 

nor a highly accurate way of measuring entire 

breeding bird populations in forest habitats. 

It is, however, a very effective way to 

determine how many pairs of certain species 

are present. It also makes it possible to 

distinguish migrants from summer residents 

and, to some degree, non-breeding from 

breeding individuals. Color banding can be 

used to define the ranges of individual birds 

and also can point out errors in judgment that 

occasionally occur when the observer relies 

entirely upon the mapping method. Bear in 

mind, however, that home ranges of many 

species are much larger than their singing 

territories (Fig. 16). 

Frochot (1978) has compared mapping, LPA, 

and banding techniques in the same oak forest 

plot of 100 hectares. Comparing the results 

for 12 common species, he determined a density 

of 49.9 breeding pairs per 10 hectares by the 

mapping method as compared with 47.0 by the 

IPA method (with appropriate corrections for 

conspicuousness). Banding data sufficient for 

computation of population estimates were 

available for only 4 of the 12 species, but 

for 3 of these 4 species the estimate from 

capture-recapture was higher than that 

obtained by either of the other two methods. 

Frochot reported that the IPA census required 

nearly 10 hours of prime time in the early 

morning, while the mapping census required 43 

hours, and the banding study took 400 hours. 

The chief advantages of the capture-recapture 

method emphasized by Frochot are: 1) it 

permits a census of females and young as well 

as of singing males, 2) it can be used for 

testing mapping and IPA methods, and 3) it 

gives additional information about daily range 

and habitat utilization of the individual 

birds. 

Nest Finding 

To the uninitiated, nest Eindfng appears 

to be the obvious way to determine accrrrately 

the breeding bird population of a forest plot, 

In actual practice, however, it is seldom 

possible to find enough active nests of a 

species to use this method as a measure of the 

breeding population--especia2Ly in ferest 

habitats. While a nest census is effective 

for many cokanial. cesting specjes, such as 

herons and ibis, there are very few Eorestnestkng species that are cnloniai. 

Nest censuses have been conducted 

successfu1L-y for a few species such as the 

Red-shouldered Hawk (Steward 1949, Henny 

- al. 1973). They have a3 so been successful in 

a few habitats, especially in residential and 

park areas, where a high percentage of the 

nests are within LO feet of the ground and 

where nests tend to be clustered in suitable 

strips of vegetation rather than scattered 

more or less randomly throughout the entire 

study plot. In a normal situation, nesting is 

spread over a period of at least 4 to 6 months 

and during this time nests are continual3y 

being destroyed or deserted and additional 

nesting attempts initiated. In the southern 

United States there is probably no one time 

when all members of a given species are 

nesting, so that even if it were possible to 

locate every nest during some particular week, 

this still would not be a census of that 

species in the plot. TomiaLojk (1974) studied 

nesting behavior of 17 pairs of Woodpigeons 

(Columba ) near WrocYaw in Poland and 

found that no more than 6 of the 1-7 had active 

nests at any one time (fig. 17). 

A good example of a nesting study of a 

single species is a Wood Thrush investigation 

in a 14.4 ha Delaware woodlot by Longcore and 

Jones (1969). Systematic nest searches were 

conducted during a 3-month period in 1965 and 

again in 1366. Grid lines located at 150-foot 

intervals were traversed at least once every 3 

days except for a 2-week period in July 1965. 

A total of 142 Wood Thrush nesting attempts 

were documented Cfig, 18) of which 38% were 

successful. This study was supplemented by an 

intensive banding effort every 2 to 3 weeks 

during the 1966 breeding season, This effort 

resulted in 46 Wood Thrushes being banded. 

This study was directed primarily toward 

deternrining reproductive success rather than 

ineasuring the population, but it gives an idea 

of how much effort would be involved in 

gathering enough information about a single 

species to get an accurate measurement of the 

breeding population, 

In sumary, I do not minimize &he importance of actual nest counts as a supplement to 
( L APRIL -L MAY JUNE A 

Figure 17.--Nesting status of 17 pairs of 

Woodpigeons near WrocYaw, Poland. Symbols 

mean: l--cooing male, 2--pair showing 

breeding behavior, 3--date of discovery of 

nest and period it remained active, 

4--successful nest. From Tomia2ojk (1974). 

other methods; I simply question their 

practicality as a census method under normal 

circumstances. There are, of course, 

exceptional cases where populations of an 

individual songbird species can be determined 

by a thorough search for nests--but this 

normally requires a prohibitive amount of 

field work. For many canopy species it would 

be nearly impossible to find all the nests 

even with a large crew of observers. 

Species Studies 

When interest relates primarily to a 

single species or a small group of species, 

considerable time may be saved by a knowledge 

of the habits of the particular species. For 

the Scarlet Tanager, for instance, there is a 

very short period just at dawn when singing 

reaches a high peak. By scheduling trips to 

include this critical period and by moving 

I I I I 

May June July August 

Figure 18.--Three point floating averages 

for the daily number of active Wood Thrush 

nests in a 14.4 ha woodlot in Delaware, 

1965-1966. From Longcore and Jones (1969). 

rapidly through the area while the birds are 

at their peak of song, the total amount of 

field time can be reduced. 

Tape Recordings 

For many species, playback of tape 

recordings can be used to induce song from 

silent territorial males. The technique may 

increase census accuracy, especially for 

species with low song activity, with a minimal 

expenditure of time. Also, the technique can 

be used to determine territorial boundaries. 

Indiscriminate use of tape recordings on 

repeated visits during the breeding season, 

however, can bias one's results because birds 

may alter their habits or their territorial 

boundaries if they believe a competing member 

of the same species is holding territory 

nearby. 

WINTER SEASON TECHNIQUES 

Winter Bird-Population Study 

In 1948 the National Audubon Society 

inaugurated an annual Winter Bird-Population 

Study, which is published in American Birds. 

The purpose of this study is to obtain an 

estimate of the average number of birds using 

a particular habitat, Many observers use the 

same plot in which they have conducted a 

Breeding Bird Census by spot-mapping. Most 

plots range in size from 6 to 20 ha. The 

plots are visited from 6 to 10 times in midwinter and the totals for each species are 

averaged. As in the Breeding Bird Census, the 

results are expressed in terms of birds per 
MORNING AFTERNOON 

Figure 19.--Comparison of morning (left) and afternoon distribution of 

birds in an upland deciduous forest in Howard County, Maryland, 22 

January 1978. On cold days in winter, birds tend to be attracted to 

sunny exposures. Squares are 250 feet on each side; elevations are in 

feet . 

square kilometer and birds per 100 acres. 

Several visits per winter are necessary 

because populations and even the species 

present in a given plot vary from day to day 

and from morning to afternoon. Finches, 

robins, and waxwings for example, often range 

over many square kilometers in the course of 

two or three days. Many other species are 

loosely attached to mixed flocks, which may 

range widely, in and out of a study plot. 

Such flocks tend, especially on cold days, to 

favor sunny exposures (fig. 19), to concentrate in the better feeding sites, and 

to avoid windy areas. 

Even when plots are covered during the 

best weather conditions, results must still be 

considered as minimum population estimates 

because rarely is it possible to find all the 

birds that are present within the plot at any 

given time--especially in a forest habitat. 

Difficulties not withstanding, the 

method does give an opportunity to compare 

populations of different habitats and, to a 

lesser degree, to follow population trends 

over a period of years. Webster (1966) 

analyzed the results of 248 winter studies in 

forest habitats and 25 studies in grasslands. 

By plotting species richness against population density he found that southern pine 

forests mixed with oaks or gums tended to have 

a higher species richness than did other 

eastern forests. 

This method can be used effectively to 

obtain indices of winter use. I should 

stress, however, that winter bird populations 

vary enormously from year to year at any one 

place, so it is highly desirable to conduct a 

winter population study for at least 2 years. 

A critique of this method (Robbins 1972) 

showed that in forest habitats 6 trips were 

sufficient to obtain a stable minimum estimate 

of the total wintering bird population, but 

that at least 8 or 10 trips were required to 

obtain such estimates for individual species. 

Christmas Bird Count 

The Christmas Bird Count (CBC), sponsored 

by the National Audubon Society since 1900 and 

published annually in American Birds, is the 

best known and probably the most used source 

of information on geographical distribution of 

nongame birds in winter. 
Figure 20.--Winter distribution and relative abundance of 

Red-tailed Hawk in 1972. From Bystrak (1974). Compare 

with figure 8, bearing in mind the difference in scales 

of abundance. 

As many as 1,275 circles, 15 miles in 

diameter, are covered annually in North America. Observers keep a record of party-hours 

and party-miles in the field, and estimate the 

time spent in each major habitat. 

Maps showing the distribution and relative abundance of 143 species, based on 

Christmas Bird Counts (fig. 20), were compiled 

by Bystrak (1974) and similar maps for a few 

dozen other species have been published from 

time to time in American Birds. These maps 

are sufficiently detailed that likelihood of 

occurrence of these analyzed species in any 

particular forest area in the Southeast could 

be estimated on the basis of availability of 

suitable habitat. 

Christmas Count data also can be used for 

comparison of winter bird populations of any 

particular forest area with those of published 

studies in the same or nearby counties. 

Winter Bird Survey 

In an effort to design a more standardized method of assessing bird populations in 

winter, the Maryland Ornithological Society 

undertook a Winter Bird Survey in central 

Maryland for 5 consecutive years, 1970-L974. 

Preliminary tests showed that the Breeding 

Bird Survey method would not be practical 

because of heavy traffic problems on many 

roads in the first few hours after sunrise in 

winter and because lack of singing made it 

difficult to detect birds that could not be 

seen from the roadside (Robbins 1970). 

The method adopted, therefore, involved 

transects of 8 km (5 miles) that were covered 

on foot in the first 4 hours after sunrise. 

One route was established at the center of 

each 7 1/2-minute Geological Survey map in 

central Maryland, giving an 11 x 14 km grid. 

An effort was made to lay out each route in 

the form of a square, 2 km on each side. Many 

routes were forced to depart from the square 

shape because of streams, ponds, buildings, 

high fences, and other obstacles; but despite 

changes in shape, the total length of 8 km was 

maintained. By timing their walking speed for 

the first quarter of the route, observers were 

able to arrive back at the starting point 

within a very few minutes of the prescribed 

4-hour period. A separate count was kept for 

each hour, and birds identified at a distance 

greater than one-quarter mile were recorded 

in a separate column on the form. 

I 

Most of the 46 routes were covered each 

year, and because coverage was standardized, 

the population changes from year to year could 

be analyzed statistically. Significant 

changes were found for many species. The 

Winter Bird Survey data also were used to map 

the relative abundance of various species 

throughout central Maryland (Bystrak and 

Robbins 1972, Robbins and Bystrak 1974). 

Comparison with Christmas Bird Count Data 

There were four CBC circles within the 

area covered by the Winter Bird Survey. This 

permitted direct comparison of the results of 

the two methods. Although published CBC's, 

from their inception in 1900, have included 

the number of hours of field coverage, this 

coverage varies enormously among areas and 
landscape are now hiked each winter 

(Samalisto 1974). 01 

J-( 

In Sweden the winter transects consist of 0 

c twenty 5-minute stops (Ksllander 1478). Each 

:, 20 transect Is covered monthly from Sovember Ct through March with the same stops, same time, (d 

cir and same observer each year. The data from 

ts SONG SPARROW both Finland and Sweden are entered on punch 

LI cards and analyzed statistically to show 

E 10 national trends in winter populations. 

m 

"tl 

-4 

A TECHNIQUES FOR OTHER SEASONS 

Transects I 1 

Figure 21.--Comparison of bird population 

trends as shown by Winter Bird Survey (solid 

lines) and Christmas Bird Count (dashed 

lines). 

* 

from year to year. Because of the changes in 

coverage, changes in observers, and lack of 

control over weather conditions, the CBC data 

have been believed too crude for application 

of statistical analysis. Comparison with the 

Winter Bird Survey data, however, revealed 

that the CBC's show year-to-year trends very 

similar to those detected in the same geographic area by the Winter Bird Survey (fig. 

21). Species commonly seen along roadsides 

and at feeding stations were recorded in 

larger numbers (per 4 hours of field work) on 

the CBC, while species typical of fields and 

forests were found in larger numbers on the 

Winter Bird Survey. Nevertheless, the 

year-to-year trends were similar, suggesting 

that, despite the disadvantage of uncontrolled 

variables, CBC's can be used in a general way 

to show population changes. The advantages of 

the CBC data are the large number of years 

represented and the large sample of 

observations each year: as many as 200-300 

party-hours concentrated in a small area. 

The transect method has been the one most 

frequently used to monitor year-around changes 

in bird populations. Admittedly, its accuracy 

varies with season of the year depending upon 

activity of the birds and visibility across 

the various habitats. Width of the transect 

strips has varied with the several authors, 

and no attempt has been made so far to 

standardize strip width among investigators 

in different countries. 

Most transect workers have walked alone, 

but Stewart et al. (1952) in a 2-year study at 

the Patuxent Research Refuge in Maryland, used 

3 observers walking parallel lines 100 m apart 

to sample a strip 300 m wide and 4.2 km long 

(about 123 ha). During the breeding season 

the observers worked strictly from the census 

lines, but at other seasons they departed as 

far as 50 m from the census lines whenever 

necessary to get better counts of flocking 

birds. Two observers often worked together on 

the same flock to obtain the best estimate of 

flock size and composition. It was believed 

that by having three observers the errors in 

estimating lateral distances were minimized as 

was the likelihood of obtaining poor estimates 

of flocking species. 

Transect Sampling in North Wales 

European Winter Transects 

The Winter Bird Survey method was tested 

simultaneously in the British Isles and in 

Maryland, The British had some reservations 

about the success of their program, largely 

because of high variability caused by wandering Lapwings, a plover that occurs in large 

flocks and moves gradually from east to west 

across the British Isles as the winter 

progresses. Hence, the British study was 

discontinued and the results were not 

published. 

A series of walking transects, varying 

from 2 to 30 km in length, was initiated in 

Finland in 1956. About 6500 km of Finnish 

To determine bird use on nine national 

nature reserves in the county of Merioneth, 

North Wales, the Nature Conservancy established a program under which 50 km of heather 

and 50 km of grassland would be censused by 

transects during each month of the year 

(Jones, 1974). Each transect belt was 200 m 

wide and the right angle distance to each bird 

fron the transect line was estimated. This 

long-term study began in 1968 and was to 

continue until the sample for each month in 

each major habitat reached 50 km. Jones used 

the method of Gates etal. (1968) and Emlen 

(1971) to convert transect data into an 

estimate of the total population, using a 

coefficient of detectabiiity. This method is 
be obtained. Attempts to monitor migratory 

populations by banding are most successful 

where shorelines, mountain ridges, river 

valleys, oases, or other topographic or 

vegetational features help to concentrate the 

migrating birds. 

One important advantage of monitoring 

migrants by trapping and banding is that mist 

nets are especially effective for birds of 

heavy underbrush and dense thickets; such 

birds are rarely seen and are almost 

impossible to detect when they are not 

singing. While mist nets are highly effective 

for capturing migrants, it must be born in 

mind that they cannot be used effectively on 

a daily basis during breeding or winter 

seasons because the birds rapidly become 

familiar with the placement of the nets and 

learn to avoid them. It should also be 

emphasized that use of mist nets is a 

specialized technique that requires special 

Federal and State permits, which are granted 

only to workers with considerable training and 

experience. 

DISCUSSION 

The above comentary gives the research 

0 biologist a considerable selection of methods '0 <I from which to choose. Each method has severe 

limitations if one's objective is to achieve 

Figure 22.--Daily bandings (birds per 1000 an accurate measurement of the absolute size 

net-hours) of American Redstart at Ocean of bird populations, especially if abundance 

City, Maryland, September and October 1966, of one species must be compared directly with 

abundance of other species. 

more likely to be successful in open habitats 

such as those used by Jones than in heavily Attempts to measure statistical error of 

forested habitats where many birds at close bird census results will be frustrated by 

range can escape detection. almost insurmounta'ble biases associated with: 

(I) daily or even hourly changes in the 

Bird Banding populations being sampled; (2) daily changes 

in behavior such as nesting activities and 

When banding is done consistently singing (Weber and Theberge 1977) ; (3) effects 

throughout a migration season, it provides quan- of different weather conditions on audibility, 

titative data on populations of those species visibility, and behavior of the birds and of 

that are readily trapped under the conditions the observers; (4) differences, even slight 

that prevail at the particular banding site. ones, in time of day as it affects bird 

The records of the major bird observatories activity (Robbins and Van Velzen 1970); (5) 

in North America (and also of those in differences among observers; (6) differences 

Europe) provide an excellent sampling in attentiveness of even a single observer; 

of a wide variety of species and have an (7) differences such as walking speed 

additional advantage in that reliable age (Coiquhoun 1940) or the exact route the 

ratios for each species for the particular observer follows from day to day; and (8) lack 

locality are obtained. As in any study during of information on the absolute numbers being 

the migration periods, weather has a major estimated. 

effect on daily counts of migrating birds 

(fig. 22) and also causes problems such as Design of the procedures and selection of 

local concentrations or overflights, any of experienced personnel to conduct the field 

which may reach major proportions and make it work and analyze the results are no less imfrustrating to attempt statistical analysis of portant than the selection of census methods. 

data from a single year. Over a period of The objectives of the study and the time frame 

years, however, a good statistical sample can in which it must be completed will dictate 
which method, or more Likely, which 

combination of methods, will be most efficient. 

Attempts should be made to minimize effects of 

as many as possible of the inherent variables. 

The bulk of the field work should be 

concentrated in the earby morning when 

activity is greatest and most consistent. 

Except for studies of migration itself, the 

migration periods should be avoided and work 

should center on the peak of the nesting 

period or the middle of winter. Census work 

should be standardized with relation to 

sunrise (or sunset). Minimum weather 

standards for field work should be 

established. Observers with considerable 

experience in census work should be chosen, 

bearing in mind that most of the censusing of 

forest birds is done by ear. Most biologists, 

whatever their level of general knowledge, 

lack the specialized skills required. 

Observers should be calibrated, rotated among 

the various tracts being compared, and for 

studies lasting more than 1 year, enlisted for 

the duration of the study. 

It is desirable to assess the accuracy of 

the method or methods being used. This is 

frequently best accomplished by a more 

intensive study of two or more of the sample 

plots. 

CONCLUSIONS AND RECOMMENDATIONS 

2. Although bird censuses are imprecise, 

they have considerable value in a relative 

sense. 

2, If the techniques are designed so as 

to minimize effects of variables that can be 

controlled, valid comparisons may be made 

among bird populations of two or more plots. 

3, The spot-mapping method is recomended for greatest precision, and when a study is 

to be repeated over a period of years. 

Carefully standardized transects or point 

counts are most effective when many plots are 

being compared, and relative rather than 

absolute numbers will suffice. 

4. Any method selected may be calibrated 

by a more thorough coverage of sample plots by 

the same or another method. 

5. Demand for data on bird populations 

and species composition in specific habitats 

is increasing rapidly. Therefore, the results 

of census work should be published or at least 

made available through data banks or other 

means. 

I thank Douglas Mitchell for preparation 

of the illustrations, Kathleen Hall for typing 

and formatting of the manuscript, and Robert 

Whitcomb, Kathleen Klimkiewicz and Danny 

Bystrak for constructive criticism of the 

manuscript. 

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Thursday l-iorning, January 26 

Research Plans 

Xoderator: Michael R. Lennartz 

Southeastern Forest Experiwen t St at ion 
A Representative Sample of Ongoing and Planned Nongame Bird Research 

in the Southeastern Region United States 

I/ Robert L. Curtis, Jr.- 

Abstract,--This paper highlights the ongoing andplanned 

nongame bird research efforts in the goutheastern Region of 

the United States. Over 40 percent of all sampled ongoing 

research is directed toward threatenedand endangered species. 

The U.S. Forest Service and various southern universities 

are the agencies most heavily involved in nongame bird 

research. A comparison of ongoing research with previously 

defined nongame bird information needs is presented. 

INTRODUCTION 

Two and one-half years have passed since 

many of us met at the Symposium on Nanagement 

of Forest and Range Habitats for Nongame Birds 

in Tucson, Arizona. 

If a consensus of opinion regarding 

information needs was reached at that symposium 

it was perhaps that management of nongame birds 

and their habitats is a relatively new resource 

issue and that there is a serious scarcity of 

information available to land managers and 

resource decision makers for formulating and 

assessing management programs. 

Michael Lennartz and Ardell Bjugstad, who 

highlighted information and research needs for 

nongame bird habitat management, stressed that 

any discussion of management information on 

research needs nust followsomeunderstanding of 

what management is or what management should 

attempt to achieve. 

I doubt that we were able then, or could 

now, agree on this point. However, two 

philosophies for management and research for 

nongame birds tended to recur throughout that 

spposium. These are: 

1. Native vegetative comunities or habitat 

types must be protected and enhanced in 

order to protect and perpetuate . 

representative native avian comunities, 

and 

2. Endangered and threatened species and 

their habitats must be protected and 

perpetuated. 

If we accept these as broad management 

guidelines, then the question becomes, what 

information do land managers need to meet 

them? Is this information being procured 

through our ongoing research programs? 

The first portion of this question 

has been answered in a large part by 

Lennartz and Bjugstad (1975) with help from 

their fellow professionals at Tucson. 

The focus of this presentation will 

hopefully shed some light on the second 

portion of the question. Just how far have 

we come since that first nongame bird 

symposium in 1975? Have we as a professional 

working group been successful in establishing 

a nongame bird research direction, and are we 

addressing the priority information needs 

which were identified two and one-half years 

ago? 

METHODS 

In this presentation, I have attempted 

to assemble a representative sample of 

ongoing nongame bird research efforts in the 

southeastern states. Attempts were made to 

sample a diverse selection of both Federal 

and state agencies having different research 

and management mandates. Colleges and 

universities, as well as private conservation 

organizations, were also queried. The entire 

I/ Robert L. Curtis, Jr., Wildlife geographic range of the southeastern region 

~iolo~ist , Division of Forestry, Fisheries, was covered, extending from the Atlantic 

and Wildlife Development, Tennessee Valley coast to Texas, Oklahoma, Missouri, and 

Authority, Morris, Tennessee 37828. Arkansas. 
A total of 35 questionnaires was 

distributed to nongame bird researchers in 

this region. Twenty-six investigators 

responded to my inquiry and provided me 

with a listing and description of 84 ongoing 

nongame bird research projects which form 

the substance of my presentation. Asummary 

of vital information regarding each project 

is included in the Appendix, 

To facilitate discussion and presentation, I have sorted the research projects 

into eight categories based upon the title, 

objectives, species or group of species, 

and, in some cases, study methodology. 

Although scme projects could, of course, 

fit into more than one category, my sorting 

approach does provide an organized framework for discussion, presentation, and 

comparison. 

planning in conjunction with other 

resource outputs--e,g., timber, forage, 

and water , 

4, lnf ormat ion on avian conmunit ylforest 

cornunity associations, 

5. Accelerated research emphasis on climax 

or mature vegetative cormunities and 

microhabitat components--e.g., snags and 

cavity trees. 

6. Infomation concerning habitat requirements and rnanagenient for endangered and 

threatened species, This latter need 

was ranked, elmost withaut exception, 

as the highest priority of both managers 

acd researchers. 

ONGOING NONGB BIRD RESEARCH - Lg;Y OVERVIEW 

The research categories include: 

1. Threatened and Endangered SpeciesEcology 

2. Effects of Forest Management Practices 

3. Species Ecology 

4. Avian-Forest Habitat Associations 

5. Structural Niche Determinations 

6. Surface Mining Impacts on Avifauna 

7. Electric Transmission.Line Impacts on 

Avif auna 

8. Raptor Investigations 

PREVIOUSLY DEFINED INFOKUTION NEEDS 

Before discussing each of the research 

categories and the current research programs 

I will quickly summarize the priority 

information needs identified by Lennartz and 

Bjugstad (Ibid. ) . These were: 

Infomation Needs 

I. Infomation allowing managers to assess 

the impacts of management systems on 

nongame birds and their habitats. 

2. Greater quantitative explanations of 

the distributive niche selection of 

avian species and cornunities through 

accelerated use of multivariate analysis 

techniques. 

3. A characterization of the extent, 

distribution, and condition of the avian 

resource base for use in avian management 

With the above information needs in mind 

let me now provide an overview of the ongoing 

nongame bird research program, 

Figure 1 presents the results of my 

regionwide inquiries and discussions with 

nongame bird investigators. The figure 

provides a category breakdown of all 84 

research projects, and the percentage 

contribution of each category to overall 

regional research activities. 

Two categories of research, threatened 

and endangered species investigations, and 

studies into the effects of forest management 

practices on avifauna, account for 49 of the 

84 projects or 58 percent of the sc~mpled 

research activity. The Lion's share of this 

research effort belongs to threatened and 

endangered species, which account for 37 of 

the 84 studies for an impressive 44 percent 

of the sampled ongoing research, 

The third most active research category, 

investigations of species ecology, is represented by 11 projects accounting E0~13percent 

of aLIresearchactivity. Studies onavianforest habitat association saccouat for 1.t 

percent. The other five categilrieseachaccount 

forlessthan10percentofallresearch. 

RESEMCM CATEGORIES 

Threatened and Endangered Species 

Clearly, an impressive impetus has 

rapidly developed for the endangered species 

research program, The high level of support 

which this program now enjoys is a result of 

an awakened public concern and interest as 

well as a better understanding sf man's role 

and moral responsibility regarding species 

sxt inc t ion. 
RESEARCH 

CATEGORY 

Transmission line 

effects 

Raptor research 

Stripmining elfects 

Quantification of 

structural niches 

Avianlforest type 

associations I 

Species ecology 

Forest management 

effects 

I 

The Endangered Species Act also requires 

that all Federal or Federally funded land 

management programs protect endangered 

species and their habitat (Ibid,), To do so 

requfres a quantum jump in available infomstion, In response to Endangered Species Act 

requirements for increased protection and 

management, we find a substantial portion 

(44 percent) of southeastern nongame bird 

research centered about endangered species 

problems. 

Prom figure 2, it is readlly apparent 

that the Red-cockaded Woodpecker Is the 

endangered species receiving most of our 

research attention. Approximarely one-third 

of the research projects directed toward the 

Red-cockaded Woodpecker are being sponsored 

by the U.S. Forest Service, Southeastern 

Forest Experiment Station (Lennartz and 

Boaper, 1976). The objective of their 

research is to determine the essential 

habitat elements selected by Red-cockaded 

Woodpeckers throughout their home range, so 

Threatened and that forest managers can assess, or predict, 

endangered the effects of alternative forest management 

I strategies on woodpecker populations. I I I I I I 

10 20 30 40 50 

PERCENT OF ONGOING SPECIES 

RESEARCH ACTIVITIES I 

Osprey 

Figure 1.--Percent composition by categoryfor 

sampled ongoing nongame avian research in 

the Southeastern Region as determined by a Seaside Sparrows 

survey conducted in October 1977. 

Peregrine Falcon 

Conceptually the info 

endangered species are no 

any other avian species. We need the same Golden Eagle 

information regarding population, distribution, resource utilization, and habitat Swainson's Warbler 

selection. But the needs are urgent; the 

time frame is critical. Bachmank Warbler 

The endangered species experience 

graphically illustrates that the future of 

wildlife in America is dependent upon much 

more than just our understanding of wildlife 

ecology. Law, economics, and politics will 

have increasing impact on wildlife populations and programs. For example, as 

Lennartz and Bjugstad (Ibid.) point out, 

the plight of species headed for extinction 

has become one of our most publicized and 

emotional contemporary wildlife problems. 

This interest, whether emotional or 

pragmatic, has been translated into active 

programs through Federal legislation 

(Endangered Species Act of 1973). Admittedly, 

not all of the support intended in the Act 

has materialized, but a firm foundation has 

been established. 

Bachman's Sparrow 

Bald Eagle 

Red-cockaded 

Woodpecker 

10 20 38 40 50 60 

PERCENT OF THREATENED 

OR ENDANGERED 

SPEC! ES RESEARCH 

Figure 2.--Percent composition by species for 

sampled ongoing threatened and endangered 

species research in the Southeastern Region 

as determined by a survey conducted in 

October 1377. 
The U.S. Forest Service's interest is 

understandable in light of Chamberlain's 

(1974) report that ". . . the National 

Forests of the Southern Region are extremely 

important to the Red-cockaded Moodpecker. 

In several states it is likely that a major 

portion of the state population occurs on 

National Forest lands." 

The states of Florida, Arkansas, and 

South Carolina also have active projects on 

the Red-cockaded Voodpecker, These efforts 

are being funded primarily through the U.S. 

Fish and Wildlife Service, Endangered 

Species Act Federal Aid Program. 

Other species currently subjects of 

research include Bachan's Sparrow, 

Swainson's Warbler, Bachmanfs Warbler, 

Southern Bald Eagle, Seaside Sparrow, 

and the Peregrine Falcon (fig. 2). 

Forest Management Practices 

It is probably true, as Hamilton and 

Noble (1975) point out, that most avian 

management on our forest lands will be in 

conjunction with other management objectives 

such as timber, recreation, forage, or 

water. The demands for timber will have 

increased greatly by the year 2000, yet, if 

current trends continue, there will likely 

be less acreage available for commercial 

timber production. Obviously to produce 

enough wood and wood byproducts to satisfy 

demands requires more intensive management 

effort on those lands which will remain in 

forest production. 

Consequently, in managing for, and in 

consideration of, the avifaunal resources 

on forest lands, especially public lands, 

the ability of the manager to attain true 

multiple use will be strained to the utmost 

(Hamilton and Noble, 1975). 

Probably one of the most difficult 

tasks facing the manager will be todetermine 

the avian management objectives for an area. 

This will be even more difficult as other 

resource objectives enter into the planning 

process. 

To ensure that avian management 

planning is no less sophisticated than 

planning for the primary resource outputs, 

managers must have information regarding 

the effects of the many silvicultural 

alternatives and various cultural 

techniques possible. Understandably, 

Lennartz and Bjugstad (1975) point 

to this as one of the most pressing 

information needs of managers, 

My inquiries revealed that research 

efforts into the effects of forestmanagement 

practices on avifaunal resources is the 

second most active category of investigation 

fig 1). Twelve of the 84 projects reported 

were within this category which represents 

14 percent of sampled regional research. 

A variety of forest cutting techiliques, 

cultural systems, and forest management 

practices are currently being investigated 

(Appendix). Specifically, among them, are: 

I. The benefit of woodland openings to 

avif auna . 

2. Effects of various type conversions and 

monoculture forest systems. 

3. Effects of clearcutting, herbicide 

treatments, selection cutting, and 

various combinations of the three on 

avif auna . 

4. Effects of cable logging and whole tree 

chipping. 

5. The role of various microhabitat elements 

such as snags and nesting cavities in 

avifaunal habitat. 

Of the five primary areas listed abcve, 

the greatest amount of research is being 

directed toward the effects on avifaunal 

resources of various cutting systems, i.e., 

clearcutting, clearcutlherbicide, selection 

cutting, and whole-tree chipping. 

The general pattern of impacts directed 

on avian habitats and communities by these 

intensive timber management activities have 

been described by several authors (Thomas 

et al., 1975; Hamilton and Noble, 1975; 

Conner et al., 1975). Unfortunately, 

quantitative investigation of a more precise 

nature is almost totally lacking. Research 

which could provide indices of quantitative 

avian use of forest habitats under various 

management systems with special reference 

to habitat selection and resource is 

definitely needed. Many of the projects 

listed in the forest management practices 

category will provide this information. 

The U.S. Forest Service is the leader 

in this research effort by being either 

directly involved or lending support services 

to 10 of the 12 projects listed under this 

category of research. 

Species Ecology 

Excluding threatened and endangered 

species work, much of the current research 

can be loosely described as avian community 
ecology. 1 have included the species ecology 

category of research to capture thoseprojects 

relating to the life history of a species or 

closely related groups of species, 

Good quantitative field data on many 

facets of avian life cycles are either 

lacking, fragmentary, or comprised of small 

sample sizes, I would stress that information on both the individual species and 

the avian cornunity is essential. As Balda 

(1975) has pointed out, neither autecological 

nor specological studies alonecanadequately 

describe the patterns of habitat selection 

and resource utilization. 

Of the 84 projects, 11 were included in 

the species ecology category. This 

rzpresents 13 percent of all research 

altivities sampled (fig, 1). Included in 

t,lis category are projects relating to 

nesting ecology, foraging ecology, range 

extensions, cavity nest predation, and 

parasite ecology (Appendix). 

Avian-Forest Habitat Associations 

Zeedyk and Evans (1975) suggest that 

more emphasis should be directed toward 

developing, with the necessary supporting 

research, silviculturally oriented avian 

mnagement alternatives and guidelines. 

Among other things, coordinatedmonitoring 

of breeding bird populations would be an 

integral part of the forest inventory. 

Thus bird population trends could be 

correlated with shifting forest land-use 

trends. Lennartz and Bjugstad (1975) 

point out that foresters utilize various 

continuing inventory systems to assess the 

timber crop, and that as we become more 

knowledgeable about which birds are 

associated with which forest types, it may 

be possible to incorporate avian habitat 

assessments into existing forest inventory 

systems. 

Nine of the 84 projects reported were 

classified under the category of avianforest habitat associations studies. This 

represents 11 percent of the current 

research work (fig. 1) . Although projects 

under this category differ greatly in 

their regional scope, study methodology, and 

specific objectives, they all attempt to 

identify bird comunities associated with 

primary forest types and successional stages 

in either a portion of or the entire Southeast. 

The U.S. Forest Service cooperative 

study with Clemson University (Gathreaux, 

1977) plans a rather broad regional attempt 

at quantifying avian comunities with forest 

associations. These associations and the 

resulting avian habilrat assessment system will 

be developed primarily from existing 

literature sources wlth some field validation 

(Lennartz, personal communication). The 

feasibility of such habitat assessment 

systems is in direct proportion to the amount 

of information available regarding avian 

comunity/plant comanity associations and 

quantified parameters of habitat suitability 

(tennartz and Bjugstad, 1975). FulfJlling 

this need is one of the tasks being done by 

the Southern Forest Experiment Station in 

Nacogdoches, Texas, with the objecrive of 

elucidating the effects of stand scrucrure on 

bird population in two limited but specific 

forest types, in this case the pine and 

pine-hardwood forests of east Texas (Dicksen, 

1977). 

Studies such as these, as well as the 

others in this category (Appendix), may 

provide us with the basis for characterizing, 

on a regional basis, the distribution and 

extent of our avian resource. This type of 

information is basic, indeed essential, to 

intelligent land management planning. 

Quantification of Structural Niches 

In my sample, this category accounts for 

6 percent of the current research activity 

fig 1) Five research projects were 

placed in this category. T should point out 

that the title of this category stresses 

quantitative efforts, particularly those 

utilizing multivariate analysis, as these 

methods provide the means to most efficiently 

analyze vast amounts of acquired information. 

Originally, the niche concept was used 

to summarize the general characteristics of 

a species' natural history. This broad 

definition has since been redefined to 

describe functional relationships (Elton, 

1927), interspecific interactions, and 

feeding and nesting preferences (Conner and 

Adkisson, 1976). Several studies have 

illustrated that both the structural and 

functional aspects of vegetation are 

important in avian habitat selection (Wiens, 

1969;Axderson and Shugart, 1934). McArthuretal. 

(1962) hycorrelatingbird speciesdiversitywith 

foliage height diversity predicted the 

presence of a bird species from measurements 

of the amounts of foliage in threehorizontal 

layers. More recently, researchers have 

used both univarfate and multivariate 

analysis in approaching the determination of 

a species niche (Cody, 1968; James, 1971; 

Shugart and Patten, 13721, 

Ideally, niche information can be used 

by wildlife managers as a tool for the 
preservation of wildlife habitat* A good 

understanding of species niche requirements 

is especially important where timber 

production and wildlife must coexist 

(Bunnell et al., 1977). An analysis of 

habitat characteristics comprising a niche 

is a prerequisite to rational application 

of land wnagement systems. 

Surface Mining and Reclamation 

Effects on Avifauna 

Approximately 5 percent of ongoing 

avifaunal research is in the area of strip 

mine and reclamation impacts on avifauna 

(fig. 1). This category accounts for four 

of the 84 projects reported. There is a 

paucity of information regarding both the 

initial impacts of surface mining and the 

effects of various reclamation techniques 

on avifaunal resources. To date only 

two breeding bird studies have been 

completed on contour surface mines (Yahner, 

1973; Garton, 1974). Information regarding 

the avifaunal resources on area surface 

mines is almost as sparse, with only three 

studies having been located (Brewer, 1958; 

Karr, 1968; Terrel and French, 1975). A 

further complication is that most previous 

research has been conducted on either 

orphan mine lands or on recently reclaimed 

conventionally mined areas. 

With the increased emphasis on coal 

as a primary energy resource of the future, 

both contour and area surface mining 

activities will be accelerated in our 

southern coal production states of 

Virginia, Maryland, Kentucky, West Virginia, 

Tennessee, and Alabama. In all of these, 

surface mining has been a major source of 

habitat disruption. 

Prior to reclamation laws, thousands 

ofacreswere simply stripped and abandoned. 

The best methodologies for reclaiming these 

abandoned lands for the benefit of avifaunal 

resources as well as other types of wildlife are poorly understood at this time. 

We know which birds live in each general 

habitat type, but quantifying the relationships so chat specific reclamation models 

can be constructed has not been adequately 

achieved (Samuel and Whitmore, 19761, 

Recent passage of the new Federal strip 

mine legislation, with its back-to-contour 

provision, adds a new unexplored dimension 

to the reclamation problem. 

A knowledge of theavifaunal utilization 

of surface mined areas is an important 

element in evaluating the management of 

reclaimed areas. Breeding bird population 

parameters may be the best indicators of 

the relative health or degree of recovery 

of a mined area and are important factors in 

determining the degree of success of a 

reclamation plan. 

Expanded quantitative studles on avian 

use of surface mine habitats are a basic 

prerequisite to sophisticated surface mine 

reclmation planning. Until this information 

is available, only rudimentary management 

will be possible. 

Raptor Research 

To date, few studies have beenaddressed 

specifically to the subject of raptor 

management or conservation. mile information of importance to raptor conservation 

has been gained through studies aimed at 

other goals, progress toward comprehensive 

understanding of what is needed to sustain 

raptor populations is still in the formative 

stages. As yet, most comprehensive management efforts on raptors have been limited 

to threatened or endangered species (Snyder 

and Snyder, 1975). 

My sample indicates that this situation 

has not changed a great deal within the 

last several years. Excluding threatened 

or endangered species, 1 have listed three 

of the 84 projects in the raptor research 

category. These three projects account for 

4 percent of the ongoing research reported 

(fig. 1). 

Additionally, there are 10 projects 

dealing with threatened and endangered 

raptors listed under the endangered species 

category. Much of this work, particularly 

on the Bald Eagle, is directed toward 

nesting surveys, determination of population 

status, and distribution patterns. 

mile the current emphasis on methods 

to save the threatened or endangered raptors 

is probably appropriate, in the long run we 

should hope for a broader program--one which 

strives to ensure that those species still 

in relatively good shape do not end up on 

the endangered list, 

Electric Transmission Line 

Effects on Avifauna 

This final category includes two 

projects accounting for slightly more than 

2 percent of the ongoing research, Clearly, 

transmission line impacts have not beec 

considered a priority research area within 

the last several years. 
The information needs listed are the six 

There are two distinct types of impacts most critical areas requiring attention as 

associated with electric transmission lines. defined by Lennartz and Bjugstad (1975) and 

The first type of impact is that associated 

with the actual transmission line clearing, 

construction, and subsequent maintenance 

of vegetation, These impacts are most 

predominant where previously forested 

habitats are converted to relatively narrow 

corridors of periodically mintained shrub 

vegetation. The second type of impact 

occurs as birds strike the electric 

transmission conductors and support towers. 

Currently the U.S. Fish and Wildlife 

Service and the Tennessee Valley Authority 

arc the only agencies reporting research 

on transmission line impacts. The 

Tennessee Valley Authority research contract 

with the University of Georgia addresses 

the first type of impact, i.e., habitat 

loss or vegetative type conversions through 

consrruction and maintenance operations. 

Currently very little is understood 

regarding the second problem--birds 

striking transmission conductors and support 

towers. As evidence of increasing concern 

for this problem, a workshop is being 

organized by the Oak Ridge (Tennessee) 

Associated Universities in cooperation with 

the U.S. Fish and Wildlife Service to 

address this very question. Workshop 

objectives are to determine the scope of 

the problem of birds striking transmission 

lines and to produce guidelines for management and research on this subject. 

PROGRESS TOWm PREVIOUSLY DEFINED 

listed earlier in the presentation. By 

reviewing each of the 84 project titles and 

objectives I have made an admittedly 

subjective determination regarding the 

information needs they fulfill. Several 

projects were judged to satisfy more than 

one information need. Therefore, the 

Number of Projects and Percent columns will 

total more than 84 projects and 100 percent, 

respectively. 

The information needs in Table 1 are not 

ranked in any order of urgency with the 

exception that endangered species research 

was given the highest priority (Lennartz 

and Bjugstad, 1975). 

It is apparent that endangered species 

research is receiving a great deal of 

attention. Some may argue that endangered 

species are demanding too much attention at 

the expense of other wildlife problems. The 

fact remains that it has been ranked as our 

number one research priority and the degree 

of emphasis that it is receiving is probably 

justified. The current emphasis on 

endangered species research is, however, 

heavily weighted toward the Red-cockaded 

Woodpecker (fig. 2). 

Table I also indicates that emphasis is 

being given to the areas of (1)avianresource 

distribution, (2) impacts of forest management, and (3) climax communities and 

associated microhabitat elements. The survey 

revealed a lesser degree of activity toward 

the final two information needs: avian/ 

forest habitat association and avian niche 

selection. 

INFOWTION NEEDS 

Eleven percent of the current research 

Having presented an overview of ongoing activity is directed toward identification 

and planned avian research, I would like to of avian/forest habitat associations 

compare the ongoing programs and the (Table 1). The concept of incorporating 

previously defined information needs (Tablel). avian habitat assessments into existing 

Table l.--Previouslydefinednongameavianinformationneedsandthe 

number and percent of sampled ongoing projectswhich contribute 

to eachasdeteminedbya surveyconductedinOctober 1977. 

Onaoina or Planned Research 

I / Inf ormation Needs- Number of Projects Percent 

Endangered Species 

Impacts of Forest knagement 

Niche Selection 

Distribution of Avian Resources 

AvianiForest Habitat Associations 

Climax Cornunities and Associated 

Microhabitat Elements 

- 11 Lennartz and Bjugstad, 1975 
forest inventory systems is fairly new. As 

greater precision is required in assessing 

trends and conditions of the avian resource, 

development of a practical habitat assessment 

system for all forest types and successional 

stages should receive accelerated emphasis. 

RESEARCH 

AGENCY 

USFSiUSFWS Coop. 

TVAiUniv. Coop. 

Seven percent of the research activity 

is being directed to use of multivariate 

analysis for quantitative explanation of 

the vegetative structure of the avian 

habitat niche. Cody (1968), James (1971), 

and Shugart and Patten (1972), utilizing 

multivariate techniques, have identified 

important habitat factors of different 

avian species. Nevertheless, the application 

of multivariate statistical techniques to 

nongame bird habitat and its management 

remains at a minimum (Mann, 1977). 

Multivariate statistical techniques 

can be exceptionally useful in optimizing 

management strategies for avian resources 

and for identifying potential impacts of 

change in management policies (Shugart 

et al., 1975). Both new and experienced 

researchers should be encouraged to become 

familiar with the descriptive power and 

utility of these techniques. 

TWIEPA Coop. 

Tennessee Valley 

DOE/ Univ. Coop. 

Wildlife Service 

USFSlUniv. Coop. 

US Forest Service 

University 

AGENCY INVOLVEMENT IN RESEARCH 

As evidenced by Figure 3, almost 

one-half (48 percent) of the ongoing research 

is being conducted by university researchers, 

frequently masters' degree or doctoral 

candidates. Universities were found to be 

actively involved in a11 eight categories 

of avian nongame research. 

The U. S. Forest Service is involved 

in 26 percent of all sampled research 

activities; over half of this 26 percent 

is being handled by the Service's own 

biologists at various forest experiment 

stations in the southern, southeastern, 

and north central regions. The remainder 

are cooperative projects between the 

U.S. Forest Service and variousuniversities. 

The survey indicates that the U.S. 

Forest Service is heavily involved in two 

of the eight research categories: threatened 

and endangered species, and effects of 

forest management practices on avifauna, 

Our National Forest wildlife habitat 

programs in the past have sought to 

maximize the production of game species and 

research has been directed toward these 

ends. However, one of the greatest 

influences stimulating the U.S. Forest 

Service's new accelerated research in the 

area of endangered avian species has been 

PERCENT OF ONGOING 

RESEARCH ACTlVlTlES 

Figure 3.--Percent composition of agencies 

active in sampled ongoing nongame avian 

research in the Southeastern Region as 

determined by a survey conducted in 

October 1977. 

the responsibility placed upon Federal 

agencies by the Endangered Species Act of 

1973. In addition, the Service's mandate 

and policy to consider multiple resource 

management and use of all wildlife species, 

coupled with exploding public interest in 

nongame wildlife, have encouraged greater 

research emphasis on the unknowns of avian 

nongame management. 

State agencies are engaged in 

approximately 10 percent of the sampled 

research activity. Their involvement is 

primarily with threatened and endangered 

species, with funds being provided by the 

Endangered Species Act of 1973 and 

administered through the U.S. Fish and 

Wildlife Service. 

The U.S. Fish and Wildlife Service 

alone, and in cooperation with several 

southern universities, accounts for 9percent 

of the ongoing research. They are involved 

in a diverse mix of research activities 

including surface mine studies, electric 

transmission line impacts, avian-forest 
habitat type associations, raptor research, 

and endangered species research. The U.S. 

Fish and Mildlife Service also conducts 

and maintains data files on the National 

Breeding Bird Survey. This survey was 

started in 1965 and was designed to help 

monitor environmental quality by measuring 

changes in abundance in North American 

breeding birds. 

Research activities of the Department 

of Energy and university cooperators 

accounted for 3 percent of the sample. 

These research projects are administered 

through and directed by the Environmental 

Sciences Division of the Oak Ridge 

National Laboratory. 

Tennessee Valley Authority and TVAf 

cooperative projects make up approxirntely 

4 percent of ongoing research. The TVA 

projects relate primarily to energy 

production impacts on the avian resource 

and include research projects on surface 

mining impacts and effects of electric 

transmission lines on avian communities. 

Clearly, both wildlife management 

and research programs are having to respond 

to a new wildlife consitituency. This 

response has been a long time in coming 

but now seems to have gained a firm hold 

in what may be described as a new direction 

for the wildlife management profession. 

While hunters still comprise 10 percent 

ofthe popuZation, present estimates 

indicate that a great majority of Americans 

have an active interest in a broad spectrum 

of wildlife values other than the production of a shootable surplus. The diversity 

of our nongame birds providesanespecially 

unique and challenging opportunity for 

resource professionals to coordinate the 

management of these species with other 

forest resource outputs. Yet, for most 

wildlife professionals, mnagement of 

nongarne birds and their habitats is a 

new resource issue, and a sound information 

base far a management program is lacking 

for many species, Consequently, as 

evidence and encouragement to you, the 

managers, that substantial progress is 

being made toward filling these information 

voids, I have attempted in this presentation 

to provide a capsule sumary of our 

ongoing avian nongane research program in 

the southeastern region. I have also 

compared the ongoing research projects 

with the critical nongame bird information 

needs defined by Lennartz and Bjugstad 

(1975). 

A sumary of the salient points of 

the presentation is as follows: 

1. Endangered species research accounts 

for 41 percent of all reported nongame 

avian research in the southeastern region, 

2. Research on the Red-cockaded Woodpecker 

comprises almost 60 percent of all 

reported threatened or endangered 

species research. Approximately onethird of all Red-cockaded Woodpecker 

research is being sponsored by the U.S. 

Forest Service. 

Research effort devoted to the effects 

of forest management practices on 

avifauna is the second most active 

research category, accounting for 16 

percent of sampled research. The U.S. 

Forest Service is also the leader 

in this research effort, being either 

directly involved in or lending support 

services to 83 percent of the projects. 

4. The development of avian-forest habitat 

associations constituted I1 percent of 

the sampled ongoing or planned research. 

Once knowledge of these associations 

is developed, monitoring of breeding 

birds populations can be made an integral 

aspect of continuing forest 

inventory. It may become possible to 

predict bird population trends associated 

with shifting forest land use patterns. 

5. Effects of surface mining and reclamation 

on avifauna constitute a fairly small 

(5 percent) portion of ongoing research. 

With increased emphasis on coal as a 

primary energy resource of the future, 

surface mining activities will be vastly 

expanded. Habitat in six of our 

southeastern states (Virginia, Maryland, 

Kentucky, West Virginia, Tennessee, and 

Alabama) will be heavily impacted. 

Consequently, this area of avian research 

bears greater emphasis. 

6. Aside from research on threatened and 

endangered species, the survey indicates 

that very few raptor studies (4 percent) 

have been initiated dealing specifically 

with the subject of raptor management 

on conservation. 

7, The comparison of sampled ongoing 

research with information needs as 

defined by Lennartz and Bjugstad (1975) 

indicates that all six'critical information voids are currently receiving 

research emphasis. 
8. Apgroximatefy one-half (48 percent) of 

all ongoing avian research is being 

conducted by universities, The U,S. 

Forest Service is ths second most 

heavily involved agency being either 

wholly as: partially responsible for 

26 percent of a11 sampled research 

activity. 

L1TEMTL'W.E CITED 

Anderson, S, Et, and N, H, Shugart, Jr, 

1974. Habitat selection of breeding 

birds in an east Tennessee deciduous 

forest. Ecology, 5S:828-837. 

Balda, R. P. 

1975. Vegetation structure and breeding 

bird diversity. -'& Proceedings: A 

symposium on mnagement cf forest 

and range habitats for nongame birds. 

May 5-9, 1975, Tucson, Arizona. 

Brewer, R. 

1958. Breeding bird populations of 

strip mined land in Perry County, 

Illinois. Ecology, 33~543-545, 

Bunnell, Re C., 5, T, Kftchings, and 

C. E. Procknow, 

1977. halysis of the structural niche 

of woodpecker species in an east 

Tennessee forest. Unpublished 

manuscript, Environmental Sciences 

Division, Oak Ridge National 

Laboratory, Oak Ridge, Tennessee, 

23 PP* 

Cody, M. L. 

1968. On the methods of resources 

division in grassland bird comunities. 

American Naturalist, 1132(924):107-147. 

Conner, R, N, and C, S, Adkisson, 

1977. Principal components analysis 

of woodpecker nesting habitat. 

Wilson Bull, 89:f22-129, 

Conner, R, N., W. 6. Hooper, W, S. Crawford, 

and K. S. Nosby. 

1975. Woodpecker nesting habitat in 

cut and uncut woodlands in Virginia, 

Unpublished mnuscrigt, Virginia 

Polytechnic Institute and State 

University, Blacksburg, Virginia, 

12 PP* 

Elton, 6, 

1927. Animal ecology, Sidgwick and 

Jackson, London, England, 209 gg. 

Garton, A, W. 

1974. A comparative study of breedingbird populations an two strip mined 

areas. P?, S. Thesis, The University 

of Tennessee, Knoxville, 94 pp, 

Hamilton, R, and R. Noble. 

1975. Plant succession and interaction 

with fauna. & Proceedings: A 

symposium on management of forest 

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May 5-9, 1975, Tucson, Arizona, 

James, Frances 6. 

1971. Ordinations of habitat relationships among breeding birds. Wilson 

Bull, 83 (3) : 215-236. 

Karr, J. Re 

1968. Habitat and avian diversity on 

strip mined band in east-central 

Illinois. Condor, 70:348-357. 

Lennartz, 4f. and A. Bjugstad. 

1975. Information needs to manage forest 

and range habitats for nongame birds. 

- In Proceedings: A spposium on management of forest and range habitats for 

nongame birds. May 5-9, 1975. 

Tucson, Arizona. 

MacArthur, R. H., J. MacArthur, and 

J. Preer. 

1962. On bird species diversity. 

American Naturalist, No. 96(888): 

167-175. 

Samuel, D. E. and R. C. Whitmore. 

1976. Reclamation and management of 

surface mined areas for game and 

nongame birds in West Virginia. & 

Proceedings: International Hill Land 

Symposium, October 3-5, 1976, 

Morgantown, West Virginia. 

Shugart, H. H. and B. C. Patten. 

1972. Niche quantifications and the 

concept of niche pattern. & 

Systems Analysis and Simulation in 

Ecology 11, B. C. Patten (ed.). 

Academic Press, New York. 

Snyder, N. F. R. and Helen A. Snyder. 

1975. Raptors in range management. 

Proceedings: A symposium on management 

of forest and range habitats for nongame 

birds. May 5-9, 1975, Tucson, Arizona. 

Terrel, T. L. and T. French. 

1975. Wintering bird populations on 

coal strip mines in north central 

Alabama. Alabama Acad . of Science, 

46(1) :I-13. 

Thomas, J. W., G. Crouch, R. Bumstead, 

and L. Boyant. 

1975. Silvicultural options and habitat 

values in coniferous forests. 

Proceedings: A symposium on management 

of forest and range habitats for nongame 

birds. Nay 5-9, 1975, Tucson, Arizona. 

Weins, J. A. 

1969, An approach to the study sf 

ecological relationships among grassland 

birds. Ornithology Monographs No. 8, 

AOU, Ithaca, New York. 93 pp. 

Uahner, R. W. 

1973. Breeding-bird populations on a 

strip mined area in a deciduous forest 

in Campbell County, Tennessee, M. S. 

Thesis, The University of Tennessee, 

Knoxville, 114 pp. 

Zeedyk, W, D, and K. E. Evans. 

1975. Silvicultural options and habitat 

values in deciduous forests* 

Proceedings: A spposium on management 
of forest and range habitats for nongame 

birds. May 5-9, 1975, Tucson, Arizona. 

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The Forest Service, U, S* Department 

of Agriculture, is dedicated to the 

prrnciple of rnulti~le use managemeat 

of the Nairror;"~ forest ~GSOU~C~S for 

susial~ed ysekls 0" %ood, &#ater, $0;- 

age, w~idlnlfe, and r~creat on. Through 

forestry research, coopera!;qn with 

";e Sazres a~d pribaQe fsrest owners, 

and management of tne National 

Forests and Mat am';! G-ass!-"bs, if 

str~ves-as dlr.is%ed bv Coilgress- 

$0 provide mcreasnnqigi greater service 

to a grownqg !da:fo~,