Multiresource Inventories:

Techniques for Evaluating Nongame Bird Habitat

Raymond M. Sheffield, Resource Analyst

Southeastern Forest Experiment Station

Asheville, North Carolina

Ai?.S7’MCZ’.-Procedures for evaluating the suitability of forest lands for the breeding habitat of

individual nongame bird species and entire avian communities are presented. A multiresource inventory

of South Carolina’s forest resources, conducted by Renewable Resources Evaluation (formerly Forest

Survey), provides the necessary habitat data. Nine nongame bird species, representative ofa broad range

of habitat types, are selected as examples for evaluation. Habitat descriptions for these species were obtained from the literature and the screening criteria were formulated. The resulting estimates of habitat

extent, condition, and distribution are presented.

Keywords: Wildlife habitat evaluation, habitat parameters, multiple use.

The management of forests for nongame bird

species has gained considerable support in recent

years. Our increasingly urbanized and environment-aware society views the intangible benefits

attributed to nongame birds as being as important

as the more tangible benefits attributed to game

animals.

Esthetic values are not the only benefits derived

from maintaining large, diverse bird populations in

forest lands. DeGraaf and Payne (1975) estimated

the economic value of expenditures in the United

States directly attributed to the enjoyment of nongame birds in 1974 to be about $500 million. The

ecological role of birds in forest ecosystems is not

yet fully understood, but many studies indicate that

birds may play some role in controlling insect populations (Bruns 1960; Buckner 1966; Buckner and

Turnock 1965; Franz 1961; Koplin 1972; Morris

and others 1958; Solomon and Morris 1970; Telford and Herman 1963; Tinbergen 1960). Another

possible role is that of a monitor of environmental

integrity of our forests (Plunkett 1979).

The USDA Forest Service, with other wildlife

and conservation organizations, sponsored a 1975

symposium (Smith 1975) and several subsequent

workshops (DeGraaf 1978a, 1978b; USDA FS

1979) on the management of our Nation’s forest

lands for nongame birds. The growing need for

coordinated management of nongame bird habitat

with timber management was addressed at these

meetings. In discussing information needs for managing forest and range habitats for nongame birds at

the 1975 symposium, Lennartz and Bjugstad (1975)

stated that the most basic information needed was a

characterization of the extent, distribution, and

condition of the resource base. Such information

has not been available in the United States. They

suggested that avian habitat assessments be incorporated into existing regional forest inventories.

In this Paper, I demonstrate how multiresource

inventory data (McClure and others 1979) collected

in South Carolina may be used to estimate the suitability of large forested areas (states or portions

thereof) for selected nongame bird breeding habitat. Nine nongame bird species, representing a

broad range of habitat groups, are selected as

examples. I present the habitat evaluation criteria

for each species and resulting estimates of the

extent, condition, and distribution of habitat for

each.

HABITAT DATA

The data needed to evaluate the breeding habitat

of the selected nongame birds were collected by U.S.

Forest Service Renewable Resources Evaluation

(RRE) field crews throughout South Carolina during 1977 and 1978. The South Carolina multiresource inventory is part of a nationwide pilot

effort to evaluate all forest-related renewable

resources. These inventories are authorized by the

Forest and Rangeland Renewable Resources

Research Act of 1978. More detailed information

on the history and purpose of the inventories is

available in a paper by McClure and others (1979).

The data were collected at 4,034 permanent

sample plots established on commercial forest land

throughout the State. The commercial forest acre-
age in South Carolina totals 12.5 million acres,

representing a broad range of forest conditions

(Sheffield 1979). The State contains a small portion

of the Southern Appalachian Mountains, a large

area of rolling Piedmont laced with narrow flood

plains, an extensive belt of sandhills, and a broad

expanse of flat coastal plain interspersed with

swamps and broad flood plains. For inventory

purposes, the State is divided into three Survey

Units: (1) Southern Coastal Plain, (2) Northern

Coastal Plain, and (3) Piedmont (fig. 1). The small

mountainous area is in the Piedmont, and the sandhills in both Coastal Plain Units.

The randomly selected and systematically

spaced permanent plots were previously used exclusively for collection of timber data. Little is known

about the sampling procedures, levels of precision,

or number of samples needed for multiresource

inventories. The sampling procedures for timber,

however, are designed to provide reliable estimates

of area, inventory volume, growth, and removals at

the Survey Unit and State levels. This study of nongame bird habitat evaluation is for the entire State

inordcrtoIldnimhsampling errors.

Much of the typical timber-related data

collected for the past several years on RRE sample

plots are useful for evaluating wildlife habitat. For

instance, stand age, forest type, physiographic class,

stand size, the presence of cull trees, timber volume,

and tree stocking can be related to the presence or

absence of breeding birds. Habitat Selection by

breeding birds is related to such conspicuous features of the habitat (James 1971; Lack 1933).

Lennartz and McClure (1979) used six of these typical tinhber-related items to screen all RRE plots in

the Southeast and estimate the area of potential redcockaded woodpecker (Picoides borealis) nesting

habitat. They found definite correlations between

their estimates of potential habitat and reported

population concentrations for the woodpecker.

More specialized data were collected for the

evaluation of wildlife habitat; many of these items

were used to evaluate habitat for the nine species.

These items include the presence of natural and

artificial cover factors (rock outcrops, holes,

logging slash, etc.), tree cavities, snags, the occurrence of water, type of water, proximity of nonforest land uses, and percenw of forcat cover. The
tree cavity and snag data were found to be incomplete for cutover forest land and were not used as

evaluation criteria; the presence of decayed cull

trees was used as a substitute in some cases. This

data-collection problem has been remedied in

subsequent inventories.

A vegetative profile study (Cost 1979; McClure

and others 1979) was incorporated into the

inventory process to provide data on the lesser

vegetation. When pooled with the tree tally

information, these data provide a picture of the

horizontal and vertical vegetative structure of the

forest. This information is best depicted graphically in a profile. Figure 2 shows such a profile for a

typical 20- to 39-year-old oak-hickory stand. The

percentage of the total space which is occupied with

vegetation within each l-foot height zone is displayed and is referred to as “vegetative stocking” in

the habitat evaluation criteria for individual bird

species. To facilitate describing habitats, several

vertical vegetative layers are defined. These zones

are the ground layer (0 to 1 foot), shrub layer (1 to 5

feet), understory layer (5 to 15 feet), midstory layer

(15 to 30 feet), and the overstory layer (30 to 80 feet).

The stocking within any other defined vertical

stratum may also be computed and used to evaluate habitat.

SPECIES HABITAT GROUPS AND

SPECIES SELECTION

Habitat groups (or types) were selected and

described to represent a range of habitats from the

early to the late successional stages and with

ground-to-canopy vertical foliage strata. Thus,

forest habitat for bird species characteristic of early

successional old fields and clearcuts, climax hardwood stands, and all vertical strata can be

evaluated. A specialized bird species group was

included to represent the habitat requirements of

cavity-nesting bird species. Cavity nesters have been

found to be an important component of the total

avian community (Haapanen 1965). Other

specialized bird groups such as the raptors could be

included in similar specialized groups. The specialized bird group is also subdivided to represent a

range of successional stages and vertical strata.

The habitat groups were used to provide a

framework for evaluating entire avian communities. These groups do not necessarily represent naturalgroupings. A species which was selected

as a representative ofa particular habitat group may

also be found in forest conditions characteristic of

another group. The habitat groups ensure selection

of species representative of a wide range of forest

conditions.

The species selected for evaluation (table 1) from

each habitat group is chosen merely as a member of

that group and is not necessarily representative of

the entire group. However, the chosen species may

well be an indicator species for that group.

Anderson (1979) suggests using this indicator

species approach to management for avian communities. Each habitat group could be more fully

evaluated by selecting several representative species

for each group. Only one species is used to represent each habitat group in this Paper because the

demonstration of the techniques and process of

habitat evaluation for the entire range of habitat

groups (and, consequently, avian communities) is

more consistent with the objectives than is a complete evaluation of only one group.

The species for each habitat group were selected

because, in general, they are somewhat limited in

their distribution in time (successional stage) and

space (vertical strata). These stenotopic species have

limited adaptability to habitat variability and

requirement for a specific habitat component(s) to

complete some phase of their life cycle. Thus, these

species provide the greatest challenge and potential

for management. Wide-ranging, adaptable speties-eurytopic-present little need for management because they thrive equally well in almost any

habitat. This trait also makes habitat evaluation

difficult. For these reasons eurytopic species were

not deemed suitable for analysis by the presented

methods. All selected species breed in South Carolina and other parts of the Southeast.

Ground and Shrub Habitats

The ground and shrub habitat group is characterized by the presence of a well-developed shrub

stratum. In general, birds found in ground and

shrub habitats nest in shrubs and low saplings or on

the ground. The low vegetation also provides food

and cover. The ground and shrub habitat group is

divided into two subgroups based on successional

age.

Early successional.-These habitats generally

include the early successional old fields and areas of

recent heavy timber cutting. The absence of a welldeveloped canopy stratum best describes these habitats. Successional age of these habitats may vary

considerably, depending on the level of stocking in a

particular area. For instance, an old field supporting a dense stocking of pine may form a closed

canopy between 10 and 20 years. But the same old

field with only scattered trees may qualify as early

successional shrub habitat for 20 to 30 years or

more. The prairie warbler is selected for habitat

evaluation for this habitat group.

3
Figure 2.-Horizontal and vertical structure of broad classes of plants for oak-hickory stands, 20 to 39

years, Piedmont, South Carolina, 1977.

4
Table I.-Selected nongame bird species with symbols

used in tables 3, 4, and 5

Species Symbol Scientific name

Brown-headed nuthatch

Downy woodpecker

Eastern bluebird

Pileated woodpecker

Pine warbler

Prairie warbler

Prothonotary warbler

Red-eyed vireo

Wood thrush

BRNU

DOW0

EABL

PIWO

PINW

PRWA

PROW

REVI

WOTH

Sitta pusilla

Dendrocopus pubescens

Sialia sialis

Dendrocopus pileatus

Dendroica pinus

Dendroica discolor

Protonoraria cirrea

Vireo olivaceus

Hylocichla mustelina

Late successional.-Late successional ground Primary cavity nesters.-This group is repreand shrub habitats are characterized by the presence sented by two woodpeckers in this Paper-the

of a shrub stratum beneath a well-developed pileated woodpecker and the downy woodpecker.

canopy. This condition is most often found in The pileated woodpecker is characteristic of dense,

mature hardwood stands, but may exist in older mature hardwood and pine forests. Less mature,

pine and the transitional oak-pine stands. The wood open forests are the most characteristic habitat of

thrush is selected for evaluation from this group. the downy woodpecker.

Canopy Habitats

A well-developed overstory layer in forests provides the canopy habitat. Shrub, understory, and

midstory strata may be present but are not a necessary requirement for all canopy-dwelling bird

species. Some species may require other strata for

nesting, but the overstory stratum is the primary

requirement. This habitat group is divided into two

subgroups based on successional age.

Secondary cavity nesters.-This group is represented by three species, each somewhat characteristic of a particular forest condition. Mature pine

stands are represented by the brown-headed nuthatch, bottomland hardwood stands by the prothonotary warbler, and clearcuts and open forests

by the eastern bluebird.

TECHNIQUES FOR DETERMINING

HABITAT SUITABILITY

Pine forests.-Forests in which pine species

(Pinus spp.) make up a substantial portion of the

overstory stratum are home to several bird species.

Some of these birds occur at their greatest density in

pure pine stands and decrease in numbers with the

invasion of hardwood species. The pine warbler is

typical of such population trends and is selected for

habitat evaluation.

Hardwoodforests.-Hardwood canopy habitats

consist of a well-developed overstory stratum made

up mostly of hardwood species. Birds belonging to

this group generally appear with the emergence of

hardwood trees into the canopy of pine forests and

increase until a mature hardwood stand exists. The

red-eyed vireo is a typical representative of this

group and is selected for evaluation.

Specialized Bird Habitats

The specialized bird habitat group is separated

into primary cavity nesters (species that excavate

their own hole) and secondary cavity nesters

(species that use natural cavities and woodpecker

holes for nesting).

A major problem in quantifying the habitats of

nongame birds is that most available habitat

information is qualitative in nature rather than

quantitative (Hooper and Crawford 1969). Some of

the more recent research studies (Anderson and

Shugart 1974a, 1974b; Conner and Adkisson 1977;

James 1971; Shugart and others 1975; Whitmore

1975, 1977) have used quantitative methods to

relate the occurrence of bird species to specific habitat variables but, in general, have stopped short of

providing precise habitat guidelines for a particular

bird species. For instance, what is the optimum tree

stocking, species composition, or vegetative coverage within any particular vertical layer for a certain

species? At a recent symposium and workshop on

nongame birds, this lack of information was identified as a major deterrent to nongame bird management (DeGraaf 1978a; Smith 1975).

In this study, each sample stand is ranked as

either unsuitable habitat or as good, acceptable, or

poor habitat for each species. To rank these stands

or habitats in this manner, quantitative guidelines

5
had to be established for each habitat parameter

determined from the literature to be important to

each species’ occurrence. Since such guidelines were

usually absent from the literature, the importance of

each habitat criterion and the dividing lines between

the various habitat rankings were determined subjectively. Empirical research results should replace

these judgments in the future.

The first step in ranking is to determine which

habitat parameters are of major importance to a

particular species’ occurrence. The dividing line

between suitable and unsuitable for each habitat

parameter is established, and each sample stand not

qualifying as suitable for any of these parameters is

given an overall rank of unsuitable (code 0) for that

particular species. For example, suppose species X

can exist only in forests consisting mainly of pine

trees 30 years of age and older with well-developed

vegetative layers below the overstory. Sample

stands will be ranked as unsuitable habitat for

species X unless the stands are composed of mostly

pine trees (50 percent or more of the total basal-area

tree stocking) with a stand age of 30 years or more,

and with 15 percent or greater vegetative stocking in

any l-foot stratum below the overstory, excluding

the 0- to l-foot zone. All stands meeting each of

these three requirements for species X habitat are

suitable and are further ranked as good (code 3),

acceptable (code 2), or poor (code 1) habitat.

Ranking suitable habitats as good, acceptable,

or poor is accomplished by considering all habitat

parameters of any importance to a species’ occurrence. These variables are usually further refinements of ones used in the initial separation of

unsuitable and suitable habitats, but other, lesscrucial, variables may be considered if they contribute

to a species’ occurrence ina particular habitat. Each

habitat variable is subjectively divided into good,

acceptable, and poor segments based on the range

of values possible for that variable, excluding the

unsuitable segments. All identified habitat variables are then assigned numerical values based on

whether the variable for the sample stand falls in the

good (3 points), acceptable (2 points), or poor (1

point) range. Habitat rank is then determined from

the number of points accumulated out of the total

possible. For example, the ranking criteria for

species X are:

Unsuitable habitats.-Sample stand does not

qualify as suitable habitat if any of the following

conditions exist:

1. Proportion of live-tree stocking made up of

pine species is less than 50 percent.

2. Stand age is less than 30 years.

3 . All l-foot strata in the shrub, understory, and

midstory layers are less than 15 percent stocked with

vegetation.

Suitable habitats.-Sample stands classified as

suitable habitat are ranked according to the total

number of points accumulated from consideration

of the following items (point values in parentheses).

1. Proportion of live-tree stocking made up of

pine species:

a. 80 percent or more (3)

b. 65-79 percent (2)

c. 50-64 percent (1)

2. Stand age:

a. 70 years or more (3)

b. 50-69 years (2)

c. 30-49 years (1)

3. Vegetative stocking in l-foot stratum of

highest density in the shrub, understory, or midstory layers:

a. 65 percent or more (3)

b. 40-64 percent (2)

c. 15-39 percent (1)

Habitat Rank Determination

Total

Habitat rank Code accumulated points

Good 3 8-9

Acceptable 2 5-7

Poor 1 3-4

Unsuitable 0 0

Using these criteria, a stand consisting of only

pine species 40 years old with a maximum vegetative stocking in any l-foot stratum in the shrub,

understory, or midstory of 25 percent would be

assigned a total of 5 points and would qualify as

acceptable habitat. For this example and for the

following nine species, it is not possible for a plot to

be assigned the total point values between 0 and the

minimum number of points shown because of the

screening logic.

SELECTED SPECIES HABITAT CRITERIA

The criteria for describing and evaluating the

habitat of each selected species are taken from the

available literature for each bird.

Prairie Warbler

The primary breeding habitats of the prairie

warbler are located in the earliest stages ofa successional continuum. Intermediate or greater shrub

densities are necessary (James 1971). The shrub

layer is important since the prairie warbler nests in

shrubs and low trees (Bent 1953; Burleigh 1958;

Griscom and Sprunt 1957). These early successional

habitats may be the result of old-field succession

(Johnston and Qdum 1956; Parnell 1969; Shugart;

and James 1973; Sprunt and Chamberlain 1970) or

timber cutting (Ambrose 1975; Bent 1953; Hooper

1967; Noble and Hamilton 1976; Oelke 1966; Parnell 1964). Meyers and Johnson’s (1978) analysis of

6
numerous breeding bird censuses also confirms that

prairie warblers occur at highest densities in the

youngest stands. Some older forest stands provide

suitable habitat, provided the overstory layer is relatively open and a shrub layer is well developed (Burleigh 1958; Noble and Hamilton 1976).

The habitat screening criteria for the prairie

warbler were developed from the preceding literature citations. The presence of a well-developed

shrub stratum in stands without a closed canopy is

an overriding factor in separating suitable habitats

from unsuitable ones. Stand age is also important,

with the younger stands qualifying as suitable and

the older stands as unsuitable urrless the canopy is

open. The same three factors are used to rank the

suitable habitats into good, acceptable, and poor

classes. The criteria for evaluating prairie warbler

habitat are:

Unsuitable habitats.

1. Vegetative stocking in any l-foot stratum

more than 25 feet above the ground is 75 percent or

more.

2. All l-foot strata in the shrub layer are less

than 15 percent stocked with vegetation.

3 . Stand age is greater than 30 years unless overstory layer stocking by l-foot strata is less than 40

percent.

Suitable habitats.

1. Vegetative stocking in l-foot stratum of

highest density above the 25-foot level:

a. O-24 percent (3)

b. 25-49 percent (2)

c. 50-74 percent (1)

2 . Vegetative stocking in 1 -foot stratum of highest density in the shrub layer:

a. 50-100 percent (3)

b. 3049 percent (2)

c. 15-29 percent (1)

3. Stand age:

a. O-10 years (3)

b. 11-20 and 31 or more years (2)

c. 21-30 years (1)

Habitat Rank Determination

Total

Habitat rank Code accumulated points

Good 3 8-9

Acceptable 2 6-7

Poor 1 3-5

Unsuitable 0 0

Wood Thrush

Wood thrush breeding habitats are opposite to

those of the prairie warbler. Mature, climax hardwood stands appear to be the preferred breeding

habitat of the wood thrush, provided a light to moderate shrub or understory stratum is present (Bertin

1977; Brackbill 1943; DeGraaf 1976; James 1971;

Johnston and Odum 1956; Shugart and James 1973;

Willson 1974). Since the wood thrush nests at an

average height of 10 feet aboveground (Bent 1949;

McElroy 1974), the shrub and understory layers are

important.

The habitat screening criteria for the wood

thrush uses stand age, the presence of shrub and

understory layers, and a well-developed overstory

layer as the variables to determine whether a sample

stand is classified as suitable or unsuitable. Meyers

and Johnson’s (1978) study indicates that the wood

thrush is tolerant of a range of habitats from pine

stands 25 to 30 years old to their favored mature

hardwood stands. Several sources indicate that the

wood thrush prefers the more mesic forest stands

for breeding (Bent 1949; Bertin 1977; Shugart and

James 1973). Hence, the ranking of suitable habitats uses forest type and the presence and type of

water on the stand, in addition to the variables used

to separate suitable and unsuitable habitats. The

habitat screening criteria for the wood thrush are:

Unsuitable habitats.

1. Stand age is less than 25 years, unless there is

50 percent or better vegetative stocking in the l-foot

stratum of highest density in the overstory.

2. All l-foot strata in the shrub and understory

layers are less than 15 percent stocked with

vegetation.

3 . All l-foot strata in the overstory layer are less

than 30 percent stocked with vegetation.

Suitable habitats.

1. Forest type:

a. Hardwood types, except oak-gumcypress (3)

b. Oak-pine types (2)

c. Pine types and oak-gum-cypress (1)

2. Stand age:

a. 75 years or more (3)

b. 50-74 years (2)

c. O-49 years (1)

3 . Vegetative stocking in l-foot stratum of highest density in the shrub layer:

a. 50 percent or more (3)

b. 3049 percent (2)

c. 15-29 percent (1)

4 . Vegetative stocking in 1 -foot stratum of highest density in the understory layer:

a. 50 percent or more (3)

b. 3049 percent (2)

c. 15-29 percent (1)

5. Vegetative stocking in l-foot stratum of

highest density in the overstory layer:

7
a. 75 percent or more (3)

b. 50-74 percent (2)

c. 30-49 percent (1)

6. Presence of water:

a. Permanent water on sample acre (3)

b. Permanent water in stand adjacent to but

not on sample acre (2)

c. Temporary water on sample acre or in

adjacent stand (1)

Habitat Rank Determination

Habitat rank Code

Total

accumulated points

Good 3 14-18

Acceptable 2 10-13

Poor 1 5-9

Unsuitable 0 0

Pine Warbler

Griscom and Sprunt (1957) state that the pine

warbler is strictly a bird of the pine forests and is

hardly ever seen far from pine trees it uses for nesting. Anderson and Shugart (1974a, 1974b) found

that the pine warbler selects its habitat most

strongly on the basis of number of canopy trees, size

of canopy vegetation, and average size of understory vegetation. Pine warblers were most common

in areas with a dense canopy and sparse understory. They occur at highest densities in pure pine

stands, at lesser densities in oak-pine stands, and

disappear with the pine trees in pure hardwood

stands (Cleaveland 1973; Dickson and Segelquist

1979; Noble and Hamilton 1976; Oelke 1966; Parnell 1969; Reese 1976). Most adequately stocked

pine stands 15 years old and older offer suitable

habitat for pine warblers (Meyers and Johnson

1978).

The habitat screening criteria for the pine

warbler incorporate three variables in identifying

suitable habitats-forest type, stand age, and pine

vegetative stocking in the overstory. The overstory

layer is considered to begin at 20 feet from the

ground for the pine warbler because of the relatively young age of some suitable habitats.

Exclusion of forest types other than pine or oakpine permits stands to be classified as suitable only if

25 percent or more of the tree stocking is made up of

pine species. Suitable habitats are ranked on the

basis of three variables-pine vegetative stocking

above the 20-foot level, total pine basal-area stocking, and shrub and understory vegetative stocking.

The most favorable habitats are those with the lowest shrub and understory layer stocking. Stand age

is not used to rank suitable habitats, since evidence

suggests that habitat suitability does not increase

appreciably with stand maturity (Meyers and Johnson 1978). The screening criteria for the pine

warbler are:

Unsuitable habitats.

1. Forest type is other than pine or oak-pine.

2. Stand age is less than 15 years, unless pine

vegetative stocking in l-foot stratum of highest

density in the overstory is 40 percent or greater.

3. Pine vegetative stocking in all l-foot strata

more than 20 feet above ground is less than 30

percent.

Suitable habitats.

1. Pine vegetative stocking in 1 -foot stratum of

highest density above the 20-foot level:

a. 75 percent or more (3)

b. 50-74 percent (2)

c. 30-49 percent (1)

2. Total pine basal area per acre:

a. 60 square feet or more (3)

b. 35-59 square feet (2)

c. lo-34 square feet (1)

3 . Vegetative stocking in 1 -foot stratum of highest density in the shrub and understory layers:

a. Less than 30 percent (3)

b. 30-59 percent (2)

c. 60 percent or more (1)

Habitat Rank Determination

Habitat rank

Good

Acceptable

Poor

Unsuitable

Total

Code accumulated points

3 8-9

2 5-7

1 2-4

0 0

Red-eyed Vireo

The red-eyed vireo is found to someextent in

many forest conditions and probably has a somewhat broad environmental tolerance (Beals 1960).

However, mature hardwood stands support the

highest numbers of this bird, while pure pine stands

do not provide suitable habitat (Bond 1957 ;

DeGraaf 1976; James 197 1; Johnston and Odum

1956; Kendeigh 1945; Lawrence 1953). Lawrence

(1953) found no red-eyed vireos where less than 25

percent of the total basal area consisted of broadleaf trees. The presence of a well-developed overstory stratum is of major importance to the red-eyed

vireo (Anderson and Shugart 1974a, 1974b;

DeGraaf 1976),because it feeds on broadleaf canopy foliage insects (Bent 1950). But the presence of

subcanopy stratification has also been shown to be

of importance to red-eyed vireo occurrence (Anderson and Shugart 1974a, 1974b; James 1976; Lawrence 1953; Shugart and James 1973). Shrubs,

saplings, and low tree branches are used by the red8
eyed vireo for nesting (Bent 1950) usually at 5 to 20

feet above ground.

The habitat screening criteria used in identifying

suitable habitats include the percentage of total

basal area comprised of hardwood species, stand

age, and vegetative stocking in the overstory layer

and layers below the overstory. Ranking of suitable

habitats is based on the same criteria.

These criteria are:

Unsuitable habitats.

1. Less than 25 percent of the total basal area is

made up of hardwood tree species.

2. Stand age is less than 20 years unless hardwood vegetative stocking in the l-foot stratum of

highest density in the overstory is 50 percent or

more.

3. All i-foot strata in the 5-to 30-foot layer are

less than 15 percent stocked with vegetation.

4 . All 1 -foot strata in the overstory layer are less

than 30 percent stocked with broadleaf vegetation.

Suitable habitats.

1. Proportion of total basal area made up of

hardwood species:

a. 75 percent or more (3)

b. 50-74 percent (2)

c. 25-49 percent (1)

2. Stand age:

a. 70 years or more (3)

b. 45-69 years (2)

c. O-44 years (I)

3 . Vegetative stocking in l-foot stratum of highest density in the midstory layer:

a. 50 percent or more (3)

b. 30-49 percent (2)

c. 15-29 percent (1)

4. Vegetative stocking in l-foot stratum of highest density in the understory layer:

a. 50 percent or more (3)

b. 30-49 percent (2)

c. 1.5-29 percent ( 1)

5. Hardwood vegetative stocking in l-foot

stratum of highest density in the overstory layer:

a. 75 percent or more (3)

b. 50-74 percent (2)

c. 30-49 percent (1)

Pileated Woodpecker

The pileated woodpecker prefers dense, mature

forests for its breeding habitats (Conner and Adkisson 1977; Hardin and Evans 1977). However, coniferous and deciduous forests with medium-sized

sawtimber (15 to 18 inches diameter at breast

height, d.b.h.) will provide adequate pileated nest

trees if some of the trees are decayed or dead

(Conner and others 1975). The presence of decay in

pileated nest trees is apparently necessary to allow

cavity excavation into the heartwood. Conner and

others (1976) found that all pileated woodpecker

nest trees examined in southwest Virginia were

infected by fungal heartrots. Old-growth stands

provide optimal habitat because these fungal heartrots have had time to infest numerous trees and the

trees are large enough to contain large cavities. But

somewhat younger stands can provide adequate

habitat, especially those with large residual trees left

from prior timber cuttings.

Stand density and the presence of nearby water

appears to have an effect on the suitability of a stand

for pileated breeding habitat. Connerand Adkisson

(1977) and Conner and others (1975) found pileated

nest trees only in dense stands (137 square feet of

basal area per acre) in southwest Virginia. Pileated

nest trees are almost always near a supply of water

(Conner and Adkisson 1977; Hooper 1967; Hoyt

1957). The percentage of the area around their nests

in forest cover is also important because the pileated

tends to favor the heavily forested areas and reject

the lightly forested, highly dissected ones (Conner

and Adkisson 1977; Sprunt and Chamberlain 1970).

The variables used to identify suitable pileated

woodpecker habitat are stand age, vegetative stocking in the overstory, and percentage of forest cover.

The overstory layer begins at the 40-foot level for

the evaluation of this species’ habitat. Variables

used in ranking suitable habitats include the

presence of water on or near the stand, the presence

of medium to large sawtimber trees containing

appreciable decay, and the three variables listed

above. The criteria for evaluating pileated woodpecker habitat are:

Unsuitable habitats.

Habitat Rank Determination

Total

Habitat rank Code accumulated points

Good 3 13-15

Acceptable 2 9-12

Poor 1 4-8

Unsuitable 0 0

I. Stand age is less than 40 years for bottomland forest types and less than 50 years for all other

types.

2. All l-foot strata above the 40-foot vertical

level are less than 25 percent stocked with

vegetation.

3. A 450-acre circular area with the sample

stand as the center is less than 36 percent forest land.

9
Suitable habitats.

1. Stand age:

a. Bottomland and pine types-80 years

or more; other types-99 years or more

(3)

b. Bottomland types-60 to 79 years; pine

types-65 to 79 years; other types75 to 98 years (2)

c. Bottomland types-40 to 59 years; pine

types-50 to 64 years; other types-50

to 74 years (1)

2. Vegetative stocking in l-foot stratum of

highest density above the 40-foot level:

a. 80 percent or more (3)

b. 50-79 percent (2)

c. 2549 percent (1)

3. Presence of water:

a. Permanent water on sample acre (3)

b. Permanent water in stand adjacent to

but not on sample acre (2)

c. Temporary water on sample acre or in

adjacent stand (1)

4. Percent forest land in 450-acre area surrounding sample acre:

a. 76 percent or more (3)

b. 56-75 percent (2)

c. 36-55 percent (1)

5. Square feet of basal area per acre in trees

15 inches d.b.h. and larger with 20 percent or

more volume loss due to decay:

a. 8 or more (3)

b. 4-7 (2)

c. o-3 (1)

Habitat Rank Determination

Habitat rank Code

Good 3

Acceptable 2

Poor 1

Unsuitable 0

Downy Woodpecker

Total

accumulated points

13-15

9-12

4-8

0

The downy woodpecker is found in yards, gardens, and roadsides as well as in numerous forested

conditions. In forests, its breeding habitats are

found in earlier successional stages than are those of

the pileated woodpecker (Bond 1957; Conner and

Adkisson 1977). Thus, downy nests are located in

stands of smaller trees and lower basal area than are

those of the pileated (Conner and others 1975).

Anderson and Shugart (1974a, 1974b) found

that downy occurrence was highly correlated with

the number of sapling trees-stands with high numbers of sapling trees supported a higher number of

downy woodpeckers than did stands with few sapling trees. Downies apparently spend much of their

time foraging on these small trees in the subcanopy

strata (Williams 1975). This habit allows them to

breed in recently timbered areas provided that

enough nest trees are available (Ambrose 1975).

Adequate nesting sites are provided by snags and

live trees infected with fungal heartrots (Conner and

others 1976). Conner and others (1975) state that

stands with trees averaging 8 to 12 inches d.b.h. will

provide adequate nesting sites if some of the trees

are decayed.

The variables considered most important to

downy occurrence and used to identify suitable

habitats include stand age, vegetative stocking in

the understory and midstory layers, the presence of

residual trees in young stands, and the number of

saplings per acre. Variables used in ranking suitable habitats include stand age, the number of

saplings per acre, basal area per acre, and the

presence of trees 9 inches d.b.h. and larger containing appreciable decay. The criteria are:

Unsuitable habitats.

1. Stand age is 11 to 29 years.

2. There are less than 200 saplings per acre.

3. All l-foot strata in the understory or midstory layers are less than 15 percent stocked

with vegetation.

4. For stands age 10 or less, there is less than 10

square feet of basal area per acre in trees 9 inches

d.b.h. and larger.

Suitable habitats.

1. Stand age:

a. 60 years or more (3)

b. 45-59 and O-10 years (2)

c. 30-44 years (1)

2. Number of saplings per acre:

a. 900 or more (3)

b. 500-899 (2)

c. 200-499 (1)

3. Square feet of basal area per acre:

a. 35-70 (3)

b. 20-34 or 71-90 (2)

c. Less than 20, or more than 90 (1)

4. Square feet of basal area per acre in trees

9 inches d.b.h. and larger with 20 percent or more

volume loss due to decay:

a. 8 or more (3)

b. 4-7 (2)

c. o-3 (1)

Habitat Rank Determination

Habitat rank

Good

Acceptable

Total

Code accumulated points

3 IO-12

2 7-9

10
Poor 1 4-6

Unsuitable 0 0

Brown-headed Nuthatch

The brown-headed nuthatch prefers the open,

mature pine forests of the Southeastern United

States for its breeding habitat. Younger pine forests and mixed pine-hardwood stands provide less

favorable but suitable habitats, while extremely

young pine stands and pure hardwood stands provide no suitable habitat (Bent 1948; Cleaveland

1973; Johnston and Odum 1956; McElroy 1974;

Meyers and Johnson 1978; Noble and Hamilton

1976; Oelke 1966; Scott and others 1977; Sprunt

and Chamberlain 1970). The brown-headed nuthatch nests low to the ground in cavities excavated

in decayed tree stubs, stumps, or fence posts (Norris

1958). They are often found in burned-over pine forests since fire creates the preferred open understory

and needed nesting sites (Bent 1948; McElroy 1974;

Sprunt and Chamberlain 1970).

The habitat variables deemed most important to

brown-headed nuthatch occurrence are stand age,

percentage of total basal area made up of pine

species, and pine vegetative stocking in the overstory layer. These variables are used to identify suitable habitats. Additional variables used in ranking

suitable habitats are vegetative stocking in the shrub

and understory strata and the occurrence of fire in

the recent past. The habitat screening criteria for the

brown-headed nuthatch are:

Unsuitable habitats.

1. Stand age is less than 20 years.

2 . Less than 50 percent of the total basal area is

made up of pine species.

3. Pine vegetative stocking in all l-foot strata in

the overstory is less than 40 percent.

Suitable habitats.

1. Stand age:

a. 60 years or more (3)

b. 40-59 years (2)

c. 20-39 years (1)

2. Proportion of total basal area made up of

pine species:

a. 80 percent or more (3)

b. 65-79 percent (2)

c. 50-64 percent (1)

3. Vegetative stocking in l-foot stratum of

highest density in the 2- to 15-foot vertical layer:

a. O-30 percent (3)

b. 31-60 percent (2)

c. 61 percent or more (1)

4. Pine vegetative stocking in l-foot stratum of

highest density in the overstory layer:

a. 80 percent or more (3)

b. 60-79 percent (2)

c. 40-59 percent (1)

5. History of fire occurrence on sample stand:

a. Burned within past year (3)

b. Burned 1 to 3 years ago (2)

c. Burned over 3 years ago, or no history of

fire (1)

Habitat Rank Determination

Habitat rank

Good

Acceptable

Poor

Unsuitable

Total

Code accumulated points

3 13-15

2 9-12

1 5-8

0 0

Prothonotary Warbler

The prothonotary warbler limits its choice of

breeding habitats to swamps, river bottoms, and

other low-lying, frequently flooded areas (Bent

1953; Parnell 1969). Nests are placed in natural

cavities and woodpecker holes in snags, stumps, and

decayed cypress knees (Griscom and Sprunt 1957;

Simpson 1969). The presence of standing or running

water near the nest site appears to be of utmost

importance for the prothonotary. For instance,

Walkinshaw (1953) found in a Michigan study that

all 84 established territories of this warbler were in

the immediate vicinity of running or standing water

or in easily flooded locations. The nests were usually shaded most of the day, making the presence of

a thick tree canopy a prerequisite. Other attributes

of prothonotary warbler habitat include the absence

of a dense shrub layer and intermediate to mature

successional ages (James 197 1).

In South Carolina and throughout the

Southeast, prothonotary warblers occur at highest

densities in the coastal swamps, but are also found

in flood plain forests in the Piedmont regions (Reese

1976; Simpson 1969; Sprunt and Chamberlain

1970). The habitat screening criteria should handle

identification of suitable habitats in either area. The

criteria used to separate suitable and unsuitable

habitats are numerous. They include physiographic class, presence of water or proximity to

water, shrub layer vegetative stocking, overstory

layer vegetative stocking, and stand age. These same

variables, excepting physiographic class, are used to

rank suitable habitats. The criteria are:

Unsuitable habitats.

1. Physiographic class is other than the following: stream margin, deep swamp, cypress strand,

small drain, cypress pond, or willow heads and

strands.

2. There is no water (permanent or temporary)

recorded on the sample acre or in the adjacent

stand, or if the plot is not within300 feet ofa stream

11
greater than 30 feet in width.

3 . Vegetative stocking in 1 -foot stratum of highest density in the shrub layer is greater than 60

percent.

4 . All l-foot strata in the overstory layer are less

than 40 percent stocked with vegetation.

5. Stand age is less than 30 years.

Suitable habitats.

1. Presence of water or proximity to streams:

a. Permanent water on sample acre, or less

than I19 feet from stream (3)

b. Permanent water in stand adjacent to but

not on sample acre, or 119 to 200 feet from

stream (2)

c. Temporary water on sample acre or

adjacent stand, or 201 to 300 feet from

stream (1)

2 . Vegetative stocking in 1 -foot stratum of highest density in the shrub layer:

a. O-20 percent (3)

b. 21-40 percent (2)

c. 41-60 percent (1)

3. Vegetative stocking in l-foot stratum of highest density in the overstory layer:

a. 80 percent or more (3)

b. 60-79 percent (2)

c. 40-59 percent (I)

4. Stand age:

a. 80 years or more (3)

b. 50-79 years (2)

c. 30-49 years ( 1)

Habitat Rank Determination

Total

Habitat rank Code accumulated points

Good 3 IO-12

Acceptable 2 7-9

Poor 1 4-6

Unsuitable 0 0

Eastern Bluebird

The eastern bluebird typically inhabits open

pine stands and clearings, and nests in old woodpecker holes in standing dead trees (Burleigh 1958;

Scott and others 1977; Thomas 1946). The early

stages of succession following field abandonment or

clearcutting are beneficial to the eastern bluebird

(Shugart and James 1973). Conner and Adkisson

(1974, 1975) found that l-year-old clearcut areas

provide excellent breeding habitat for bluebirds if

nest cavities are available. Clearcuts up to 12 years

old provide suitable habitat. As stands grow older

the vegetation grows taller and more dense, thus

detracting from its suitability as bluebird habitat.

Bluebirds are known to select areas with abundant

open ground (Thomas 1946). Heard (1979) studied

eastern bluebird nesting success in clearcuts of varying ages in eastern North Carolina and found that

nesting success in artificial boxes placed in I- to 3-

year-old clearcuts was more than double that of

boxes placed in 4- to g-year-old pine stands. She

also confirmed the observations of other authors

(Pinkowski 1976; Scott and others 1977) that eastern bluebirds readily nest in the savannahlike habitats of older pine stands.

The habitat criteria used in identifying and

ranking eastern bluebird habitats reflect the two

stages of suitable habitats. Stands falling between

the early clearcut stages and the somewhat older

pine stands are excluded. Other variables used to

identify suitable habitats include forest type, vegetative stocking in the understory layer, basal area per

acre, and vegetative stocking in the overstory layer.

Only three variables are used to rank suitable habitats-stand age, vegetative stocking in the understory layer, and the history of fire occurrence. Fire

maintains the favored open ground and creates

potential nesting substrates. The habitat screening

criteria for the eastern bluebird are:

Unsuitable habitats.

1. Stand age is 13 to 19 years.

2 . Forest type is not pine for stands 20 years old

and greater.

3 . For stands 0 to 12 years old, vegetative stocking in the l-foot stratum of highest density in the

understory layer is 60 percent or greater.

4. For stands 20 years old and greater, vegetative stocking in the 1 -foot stratum of highest density

in the understory layer is 40 percent or greater.

5. Basal area per acre is greater than 60 square

feet.

6 . Vegetative stocking in 1 -foot stratum of highest density in the overstory layer is greater than 50

percent.

Suitable habitats.

1. Stand age:

a. O-3 or 60 years and more (3)

b. 4-8 or 40-59 years (2)

c. 9-12 or 20-39 years (1)

2. Vegetative stocking in the l-foot stratum of

highest density in the understory layer:

a. O-15 percent (3)

b. 16-30 percent (2)

c. 3 1 percent or more (1)

3. History of fire in sample stand:

a. Within past year (3)

b. 1 to 3 years ago (2)

c. Over 3 years ago, or no history of

fire in stand (1)

12
Habitat Rank Determination Habitat Extent and Conditions

Habitat rank

Good

Acceptable

Poor

Unsuitable

Total

Code accumulated points

3 8-9

2 6-7

1 3-5

0 0

RESULTS

A FORTRAN program was written incorporating the criteria presented. The program evaluated each RRE forest sample in South Carolina,

using the available habitat data, and ranked each

sample stand in terms of its suitability for breeding

habitat for the nine nongame bird species. Summary cards for each plot were produced with the

rankings along with other basic data about the

stand. These summary cards were used for compiling and evaluating the data. The estimates of the extent, relative condition, and distribution of habitat

are presented in this section.

When interpreting these data, the reader

should keep in mind that the criteria used to estimate area of habitat are based on general habitat

descriptions, with modifications to allow incorporation of RRE data. For this reason, the results

presented are intended to be examples and not bold

forecasts of the acreages in South Carolina on

which one should find each of the nine species. The

results do show some expected differences between

species, ownership, and regions within the State.

The acreages of habitat by suitability and species

are presented in table 2. The results seem consistent

with the qualitative descriptions of habitat and

species abundance obtained from the literature. For

instance, the eastern bluebird and the prothonotary warbler are probably the most restrictive of

the nine species in their selection of habitat; these

two species have the least acreage of suitable habitat. The prairie warbler is somewhat less restrictive,

resulting in about 25 percent of the forest land being

classified as suitable. However, most of this suitable acreage was ranked as either good or acceptable habitat. The pileated woodpecker and the

brown-headed nuthatch, both species of some concern to ornithologists, have between 26 and 30 percent of the commercial forests in suitable habitat.

However, both species have 10 percent or less of

their total suitable acreage ranked as good habitat.

The species with the most suitable habitat include

the downy woodpecker, wood thrush, red-eyed

vireo, and the pine warbler. The literature suggests

that these species may have more tolerance to habitat variability than do the other five species. This

tolerance is probably reflected by the screening criteria. Various natural and man-related forces may

have combined to create or sustain abundant suitable habitat for these and other species.

Habitat Distribution

Computer generated habitat maps, based on

actual plot locations, for each of the nine species

Table Z.-Acreage of suitable and unsuitable nongame bird habitat, by

suitability rank and species, South Carolina, 1978

Species Total

Good

Suitability rank

Acceptable Poor Unsuitable

Prairie warbler 12502.9 1,165.6 1,246.g 759.5 9,33 I .o

Wood thrush 12502.9 646.2 3,368.2 2,135.5 6,353.0

Pine warbler 12,502.9 1,823.O 2,633.l 825.0 7,221.g

Red-eyed vireo 12,502.9 1,418.9 3,400.4 659.9 7,023.7

Pileated woodpecker 12502.9 329.0 1,651.l 1,228.l 9,294.7

Downy woodpecker 12,502.9 431.1 3,760.9 2,541.7 5,769.2

Brown-headed nuthatch 12,502.9 101.5 2,680.5 933.9 8,787.0

Prothonotary warbler 12,502.9 606.9 661.8 42.2 11,192.O

Eastern bluebird I2,502.9 147.4 613.1 731.7 11,010.7

13
(figs. 3-11) show the distribution of good, acceptable, and poor habitat in South Carolina. Although

these maps also reflect the habitat acreage given in

table 2, their greatest value is in identifying concentrations of suitable habitat for a particular species as

well as areas where suitable habitat is sparse or

absent.

Most of the nine species exhibit some differences in habitat distribution. Those species that are

most restrictive in their selection of habitat show the

most striking differences. In this study, these species

include the prairie warbler, pileated woodpecker,

brown-headed nuthatch, prothonotary warbler,

and the eastern bluebird. These species also have the

smallest acreage of suitable habitat.

The prairie warbler (see fig. 3) has more

abundant habitat in the Coastal Plain region, where

several concentrations are located, than in the Piedmont and mountainous regions. Stands sparsely

stocked with trees reaching into the overstory layer

combined with dense vegetative stocking in the

shrub layers are more abundant in the Coastal Plain

region than in the Piedmont. Suitable habitat for

the pileated woodpecker (see fig. 7) is concentrated

in the Coastal Plain and the small mountainous

area. These concentrations are caused by the older

stand ages in these two regions. In the Coastal Plain,

the older stands, and thus the better pileated habitat, are located in the swamps and river bottoms.

Suitable habitat for the brown-headed nuthatch

(see fig. 9) is fairly uniformly distributed across the

State with the exception of the northwest Piedmont and mountains, where suitable habitat is less

dense. However, about 84 percent of the good habitat is located in the Coastal Plain. Only 16 percent of

the prothonotary warbler habitat (see fig. 10) is

located in the Piedmont. In the Coastal Plain, suitable habitat is heavily concentrated along the major

rivers and in the swamps. Suitable eastern bluebird

habitat is about proportionally distributed throughout the State in terms of total acreage, but the

Coastal Plain has more noticeable concentrations

of acceptable to good habitat (see fig. 11).

14
m . . . a

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Figure 6.

DISTRIBUTION OF SUITABLE

RED-EYED VIREO HABITAT

BY SUITABILITY CLASS, SOUTH CAROLINA, 1978

A GOOD HAB . * 'dh A ACCEPTAB

a POOR HAB

ITAT

LE HABITAT

ITAT
Figure 7.

DISTRIBUTION OF SUITABLE

PILEATED WOODPECKER HABITAT

BY SUITABILITY CLASS, SOUTH CAROLINA, 1978

A GOOD HABITAT

d ACCEPTABLE HABITAT

- POOR HABITAT
Figure 8.

DISTRIBUTION OF SUITABLE

DOWNY WOODPECKER HABITAT

BY SUITABILITY CLASS, SOUTH CAROLINA, 1978

GOOD HABITAT

ACCEPTABLE HABITAT

POOR HABITAT
DISTRIBUTION OF SUITABLE

BROWN-HEADED NUTHATCH HABITAT

BY SUITABILITY CLASS, SOUTH CAROLINA, 1978

Figure 9.

A GOOD HABI

A ACCEPTABL

a POOR HABI

TAT

E HABITAT

TAT
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The ownership of commercial forest land is an

important factor in assessing the nontimber

resource, as it has been for timber assessments for

decades. Varying levels of management between the

ownership groups result in differences in wildlife

habitat as well as in timber characteristics. The

physiography of the forest lands controlled by each

ownership group can also affect the kinds and

amount of wildlife habitat. Many of these differences show up when we look at the distribution of

suitable nongame bird habitat by ownership class

(table 3). The first column shows the percentage of

all commercial forests that are owned by each

ownership group. These percentages are used for

comparison with similar percentages for suitable

habitat for each of the bird species.

National Forests in South Carolina comprise

only 4.6 percent of the commercial forest land

(Sheffield 1979). These lands provide a higher than

average percentage of suitable habitat for the

pileated woodpecker, brown-headed nuthatch, pine

warbler, and downy woodpecker; however, they

provide considerably less than 4.6 percent of the

suitable habitat for the prairie warbler, eastern bluebird, and prothonotary warbler. National Forests

have a higher proportion of pine forest types, older

stands, and upland physiographic classes than does

the State as a whole (Sheffield 1979), which

accounts for many of these differences. Forest lands

controlled by other public agencies tend to be most

favorable for pine stand dwellers (the pine warbler

and the brown-headed nuthatch) and least favorable for those birds restricted to hardwood types

(red-eyed vireo).

Comparison of the commercial forest and habitat percentages for forest industry lands reveals

several differences. Forest industries control 18.6

percent of the commercial forests but provide 25

percent of the prairie warbler habitat, 29.1 percent

of the eastern bluebird habitat, and 22.8 percent of

the prothonotary warbler habitat. In contrast, only

13.3 percent of the red-eyed vireo habitat is located

on forest industry lands. These findings probably

result from the large acreage of industry land in

young-age classes and pine forest types. Almost 39

percent of the total acreage classified as deep

swamps in South Carolina is owned by forest

industries, accounting for the abundant prothonotary warbler habitat. The forest industry percentage for the eastern bluebird habitats may be somewhat inflated relative to the other ownerships

because the presence of cavities and snags was not

used as a requirement. The intensive management

practiced by forest industries often eliminates

these nesting sources. Adequate data for cavities

and snags on cutover forest lands will be available

in subsequent inventories.

The two private groups, farmer and miscellaneous private, represent an intermediate management level between the two extremes of National

Forests and forest industry. As a result, few major

differences appear between the percentage of commercial forest land and suitable nongame bird

habitat.

The relative quality of the habitat classified as

suitable for each ownership is presented in table 4.

The quality ranking for each species and ownership

was calculated by summing all the numerical ranking codes for each species and dividing by the total

number of suitable plots for that species and ownership. This calculation results in a code ranging from

1 .O to 3.0 and represents the average quality of only

the suitable habitat, regardless of the total acreage

involved. An average quality for each species across

all owners provides a basis for comparison.

The differences between the ownership groups

Table 3:-Distribution of commercial forest land, by ownership class. and of

suitable nongame bird habitat, by ownership class and species, South Carolina. 1978

.

--~.

All Species’

Ownership class commercial

forests PRWA WOTH PINW REV1 PlWO DOW0 BRNlJ

I .1..

PROW EABI.

----________________-------------- percenl -------------------------------------

National Forest 4.6 2.8 5.3 6.5 4.3 8.4 5.8 7.6 3.4 3 .o

Other public 4.1 3.6 3.2 4.7 2.5 3.8 3.4 5.3 3.5 3.6

Forest industry’ 18.6 25.0 15.6 17.1 13.3 16.7 14.5 16.7 22.x 29. I

Farmer 36.0 33.4 37.0 34.1 42.1 33.4 37.8 32.5 33.9 30.1

Miscellaneous

private 36.7 35.2 38.9 37.6 37.8 37.7 38.5 37.9 36.4 34.2

-~

‘Symbols for the species are given in table I.

‘Includes lands under long-term lease.

24
Table 4.-Average ranking of suitable habitat, by ownership

class and species, South Carolina, 1978

Ownership class

Species’

PRWA WOTH PINW REV1 PIWO DOW0 BRNlJ PROW FABI.

National Forest 2.4 1.8 2.3 2.0 1.7 I .7 1.9 2.4 1.6

Other public 1.9 1.7 2.3 2.0 1.6 1.6 1.9 2.2 I.6

Forest industry’ 2.4 1.7 2.2 2.3 2.0 I .8 1.8 2.6 1.8

Farmer 2.0 1.8 2.1 2.1 1.6 1.7 1.7 2.3 1.5

Miscellaneous private 2.1 1.8 2.2 2.2 1.8 1.7 1.8 2.5 1.5

Average, all owners 2.1 I .7

‘Symbols for the species are given in table 1.

‘Includes lands under long-term lease.

2.2 2.1 1.7 I .7 1.8 2.4 I.6

are not as pronounced for the quality of suitable

habitat as those for the distribution because the

magnitude of the suitable acreage is not a factor.

There are differences, however significant, for some

of the species.

Since the rankings in table 4 did not account for

the acreage of suitable habitat for each species,

another ranking was calculated to depict the overall suitability for each species on lands controlled by

each ownership group (table 5). This ranking was

calculated by summing all numerical ranking codes,

by species and ownership, and dividing by the total

number of plots on forest lands held by each owner

group. This species ranking code may range from

0.0 to 3.0. An overall ownership ranking is shown in

the first column.

National Forests have the highest overall ranking, resulting from higher than average species

rankings for the pine warbler, pileated woodpecker, downy woodpecker, and brown-headed

nuthatch. The other ownership rankings cluster

around the overall average. By individual species,

however, several differences become apparent. Forest lands controlled by other public agencies have

higher than average species rankings for the pine

warbler and brown-headed nuthatch and lower

than average for the red-eyed vireo. Forest lands

owned or leased by forest industries are better than

average for the prairie warbler and the eastern bluebird. Few significant departures from the species

averages are indicated for farmers and miscellaneous private landowners. Red-eyed vireo habitat is

slightly better than average on forest lands owned

by farmers.

Table S.--Average nongame bird habitat suitability ranking. by

ownership class and species, South Carolina, I978

Ownership class Owner

ranking’

Species’

PRWA WOTH PINW REV1 PIWO DOW0 BRNU PROW EABL

National Forest 6.5 0.4 0.9 I .4 0.8 0.8

Other public 5.3 .5 .7 1.2 .6 .4

Forest industry 3 5.6 .8 .7 .9 .8 .5

Farmer 5.4 .5 .9 .8 1.1 .4

Miscellaneous

private 5.7 -5 .9 .9 1.0 .5

Average,

all owners 5.6 .5 .8 .9 .9 .5

‘Individual species’ rankings may not add to the owner ranking because of rounding.

‘Symbols for the species are given in table I.

‘Includes lands under long-term lease.

I.1 0.9 0.2 0.1

.8 .8 .2 .2

.8 .5 .4 .3

.9 .5 .2 .2

.9 .5 .3 .2

- -

.9 .5 .3 .2

2.5
DISCUSSION

This study demonstrates that the habitat data

and some basic techniques needed to evaluate large

forested areas, in terms of their suitability for nongame bird breeding habitat (and the habitat of other

nongame and game species), are now available. The

results of the evaluations for the nine species seem

reasonable, based on the general habitat and

population descriptions found in the literature and

used to formulate criteria. Research results are

needed to replace the subjective criteria used in this

evaluation. Field validation efforts are also needed

to relate species occurrence and abundance to the

projected rankings for each species. Once these two

steps are accomplished, the evaluation process presented should prove to be a valuable tool.

The habitat evaluation techniques can be used to

evaluate the habitat of a single species of interest or

of entire avian communities. If quantified habitat

guidelines for a large and diverse group of nongame birds can be assembled, then the forests in the

Southeast can be evaluated for these avian communities by selecting several representative or indicator species to fit into each of the habitat groups.

Several species are needed in each group to account

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