BIOLOGICAL REPORT 82(10.106)

AUGUST 1985

HABITAT SUITABILITY INDEX MODELS:

EASTERN WILD TURKEY

.. ,\ . I.\

Fish and Wildlife Service

). Department of the Interior

SK

361

. U54

no . 82-

10 .106
This is one of the first reports to be published in the new "Biological

Report" series. This technical report series, published by the Research

and Development branch of the U.S. Fish and Wildlife Service, replaces

the "FWS/OBS" series published from 1976 to September 1984. The Biological Report series is designed for the rapid publication of reports with

an application orientation, and it continues the focus of the FWS/OBS

series on resource management issues and fish and wildlife needs.
MODEL EVALUATION FORM

Habitat models are designed for a wide variety of planning applications where habitat information is an important consideration in the

decision process. However, it is impossible to develop a model that

performs equally well in all situations. Assistance from users and

researchers is an important part of the mode 1 improvement process. Each

model is published individually to facilitate updating and reprinting as

new information becomes available. User feedback on model performance

will assist in improving habitat models for future applications. Please

complete this form following application or review of the model. Feel

free to include additional information that may be of use to either a

model developer or model user. We also would appreciate information on

model testing, modification, and application, as well as copies of modified

models or test results. Please return this form to:

Habitat Evaluation Procedures Group

U.S. Fish and Wildlife Service

2627 Redwing Road, Creekside One

Fort Collins, CO 80526-2899

Thank you for your assistance.

Speci es

Habitat or Cover Type(s)

Geographic

Location

Type of Application: Impact Analysis Management Action Analysis

Baseline Other -------------------------

Variables Measured or Evaluated

Was the species information useful and accurate? Yes No

If not, what corrections or improvements are needed?-----------
Were the variables and curves clearly defined and useful? Yes No

If not, how were or could they be improved?

Were the techniques suggested for collection of field data:

Appropriate? Yes No

Clearly defined? Yes No

Easily applied? Yes No

If not, what other data collection techniques are needed?

Were the model equations logical? Yes No

Appropriate? Yes No

How were or could they be improved?

Other suggestions for modification or improvement (attach curves,

equations, graphs, or other appropriate information)

Additional references or information that should be included in the model:

Model Evaluator or Reviewer Date ------------

Agency _

Address

Telephone Number Comm:----------- FTS
Biological Report 82(10.106)

August 1985

HABITAT SUITABILITY INDEX MODELS: EASTERN WILD TURKEY

by

Richard L. Schroeder

Habitat Evaluation Procedures Group

Western Energy and Land Use Team

U.S. Fish and Wildlife Service

Drake Creekside Building One

2627 Redwing Road

Fort Collins, CO 80526-2899

Western Energy and Land Use Team

Division of Biological Services

Research and Development

Fish and Wildlife Service

U.S. Department of the Interior

Washington, DC 20240
This report should be cited as:

Schroeder, R. L. 1985. Habitat suitability index models: Eastern wild

turkey. U.S. Fish Wildl. Servo Biol. Rep. 82(10.106). 33 pp.
PREFACE

This document is part of the Habitat Suitability Index (HSI) Model Series

[Biological Report 82(10)J which provides habitat information useful for impact

assessment and habi tat management. Several types of habitat i nformati on are

provided. The Habitat Use Information Section is largely constrained to those

data that can be used to derive quantitative relationships between key environmental variables and habitat suitability. This information provides the

foundat i on for the HSI model and may be useful in the development of other

models more appropriate to specific assessment or evaluation needs.

The HSI Model Section documents the habitat model and includes information

pertinent to its application. The model synthesizes the habitat use information into a framework. appropriate for field application and is scaled to

produce an index value between 0.0 (unsuitable habitat) and 1.0 (optimum

habitat). The HSI Model Section includes information about the geographic

range and seasonal application of the model, its current verification status,

and a list of the model variables with recommended measurement techniques for

each variable.

The model is a formalized synthesis of biological and habitat information

published in the scientific literature and may include unpublished information

reflecting the opinions of identified experts. Habitat information about

wildl ife species frequently is represented by scattered data sets collected

during different seasons and years and from different sites throughout the

range of a speci es , The model presents thi s broad data base ina formal,

logical, and simplified manner. The assumptions necessary for organizing and

synthesi zi ng the speci es-habitat i nformat ion into the model are di scussed.

The model shoul d be regarded as a hypothesi s of speci e s-hab t tat re 1ati onships

and not as a statement of proven cause and effect re 1ati onshi ps. The mode 1

may have merit in planning wildlife habitat research studies about a species,

as well as in providing an estimate of the relative quality of habitat for

that species. User feedback concerning model improvements and other suggestions that may increase the utility and effectiveness of this habitat-based

approach to fish and wildlife planning are encouraged. Please send suggestions

to:

Habitat Evaluation Procedures Group

Western Energy and Land Use Team

U.S. Fish and Wildlife Service

2627 Redwing Road

Ft. Collins, CO 80526-2899

iii
iv
CONTENTS

Page

PREFACE iii

ACKNOWLEDGMENTS vi

HABITAT USE INFORMATION 1

Genera 1 1

Food 1

Water 3

Cover 4

Reproduct ion 5

Interspersion and Composition..................................... 7

Special Considerations............................................ 8

HABITAT SUITABILITY INDEX (HSI) MODEL.................................. 9

Model Applicability 9

Model Description................................................. 10

Application of the Model.......................................... 23

SOURCES OF OTHER MODELS 28

REFERENCES 28

v
ACKNOWLEDGMENTS

William M. Healy, George A. Hurst, John B. Lewis, Terry W. Little,

Will i am E. Porter, and Dan W. Speake are gratefully acknowl edged for thei r

review of this habitat model. The cover of this model was illustrated by

Jennifer Shoemaker. Word processing was provided by Carolyn Gulzow and Dora

Ibarra.

vi
EASTERN WILD TURKEY (Meleagris gallopavo sylvestris)

HABITAT USE INFORMATION

General

Eastern wild turkeys (Meleagris gallopavo sylvestris) occupy a wide range

of habitats (Dickson et al. 1978; Bailey et al. 1981), with diversified

habitats providing optimum conditions (Bailey and Rinnell 1968; Bailey et al.

1981). Bottomland hardwood forests in association with upland forests, fields,

and pastures is the preferred turkey range in the Southeast (G. A. Hurst,

Department of Wildlife and Fisheries, Mississippi State University, Mississippi

State; letter dated December 3, 1984). Clearings and savannas scattered

throughout the forest provide important brood-reari ng, feedi ng, and dusting

sites (Bailey et al. 1981). Preferred habitat in forested regions of the

agricultural midwest consists of equal amounts of forest and open pastures or

cropland, with abundant edge between these habitats (Little 1980; W. F. Porter,

College of Environmental Science and Forestry, State University of New York,

Newcomb; letter dated December 18, 1984).

Eastern wild turkeys are residents in 34 states, from the southern tip of

Maine west to southwestern Minnesota, south through eastern Nebraska to east

Texas, and across the southern states, excluding Florida (Bailey 1980).

Food

Eastern wild turk.eys are opportunistic omnivores (Bailey and Rinnell

1968) and their diet reflects the types of plant and animal foods that are

available (Dalke et al. 1942). The average annual food intake of the turkey

consists of 90% plant and 10% animal material (Korschgen 1967). Principal

plant food groups in the diet include mast, fruits, seeds, greens, and agricultural crops. Analysis of the contents of 524 turkey stomachs from Virginia

revealed over 354 species of plants, representing 80 families (Mosby and

Handley 1943). Turkeys also eat a wide variety of animal matter (Korschgen

1967) .

Acorns are an important staple food and comprise an average of 17% of the

year-round diet by volume, and 32% of the fall and winter diet (Korschgen

1967). Acorns were eaten year round in Missouri, with monthly volumes ranging

from a trace in July to 73.3% of the January diet. Acorns comprised one-half

to two-thirds of the fall, winter, and spring foods of the eastern wild turkey

in Pennsylvania (Kozicky 1942 cited by Korschgen 1967). A variety of oak

species (Quercus spp.) should be maintained to avoid acorn crop failures, and

to help stabilize both food supplies and wildlife populations that use acorns

1
(Christisen and Korschgen 1955). Mast failures in Georgia and Alabama did not

affect turkey survival due to the general availability of alternate food

sources (Markley 1967). Turkeys in Louisiana had high population densities in

some habitats where oaks were scarce (Dickson et al. 1978). Turkeys in this

area obtained green forage from winter crops or from areas that were burned in

the winter, as well as mast from species other than oaks.

Grass leaves and seeds are important foods and are consumed most

frequently duri ng wi nter and spri ng (Korschgen 1967). Turkeys in Mi ssouri

used a wide variety of foods; optimum management practices provide for establishing and maintaining diversified habitats within their annual range

(Korschgen 1973). Food produced in forest openi ngs and open woodl ands was

used extensively by turkeys. Flowering dogwood (Cornus florida), black gum

(Nyssa syl vati ca), wil d cherry (Prunus serotina), hackberry (Celtis

oCCTdentalis), and similar trees add diversity to the food supply and improve

turkey habitat.

Food was not believed to be a limiting factor for turkeys in West Virginia

(Bailey and Rinnell 1968) or in the Georgia and Alabama portion of their range

(Mark"ley 1967). However, Davis (1976) noted that food can be a limiting

factor in areas with 1arge pure stands of pi ne (Pi nus spp.). I n an Alabama

study area dominated by young pine plantations, food was provided primarily by

other forest types (Kennamer et al. 1980). Food also may be lacking during

winters in the upper Mississippi Valley portion of the wild turkey's range

(Porter et al. 1980). Home range size and habitat use are influenced by the

available food resources, with winter food needs exerting the greatest impact

(Lewis and Kurzejeski 1984).

The food habits of eastern wild turkeys vary throughout the year (Bailey

and Rinnell 1968). Fruits of virtually all plant species are taken in season.

Spring foods in Missouri were. obtained from the following plant types

(percentages are volume measurements): trees (mostly oaks), 53.6%; farm

crops, 16.6%; forbs, 13.4%; native grasses, 3.9%; shrubs, 3.7%; sedges (Carex

spp.), 3.1%; and vines, 0.8% (Korschgen 1973). Animal foods and plant galls

provi ded the remainder of the spri ng foods. Green herbaceous growth from

wheat (Triticum aestivum), rye (Secale cereale), and alfalfa (Medicago sativa)

was an important spring food source in another Missouri study (Ellis and Lewis

1967). In West Virginia, grass is important all year, but especially in early

spring when turkeys apparently subsist on it (Bailey and Rinnell 1968).

Wheat, rye, and other similar green vegetation provides important turkey

forage in late winter and early spring (Hurst, unpubl.).

Insects are important summer foods for young turkey poults (Bailey and

Rinnell 1968; Hurst and Stringer 1975). In Mississippi, poults 3 to 7 days

old consumed 79% animal food and 21% plant food (Hurst and Stringer 1975).

The percentage of animal foods consumed declined steadily as poults got older,

and animal foods accounted for only 13% of the diet at 22 to 38 days of age.

Insects made up over 80% of the animal foods consumed. Summer foods of

juvenile turkeys in Alabama included 61.5% grasses (mostly seeds) and 15.5%

grasshoppers (Orthoptera), by volume (Hamri ck and Davi s 1972). Animal foods

were more abundant in forest openings and other areas with abundant herbaceous

growth, than in forested habi tats (Bl ackburn et a 1. 1975; Hurst and Stri nger

1975; Martin and McGinnes 1975). Forest clearings in Virginia contained 25

2
times more insects than were present under the forest canopy, and turkey

poults needed less time in clearings than in forests to obtain the same

quantity of insects (Martin and McGinnes 1975). Alfalfa fields provided

important feeding habitat in Minnesota during the spring and summer (Porter

1978).

Important fall foods of the wild turkey include crabgrass (Digitaria

sanguinalis), acorns, grass and sedge leaves, tick-trefoil (Desmodium spp.),

and beechnuts (Fagus grandifolia) (Korschgen 1967). Turkeys in Alabama fed in

more open fi e1ds and pastures in the fall, and shi fted to forested habi tats

that supplied acorns and other mast as food became less plentiful towards

winter (Barwick and Speake 1973). Fall range in the mountains of the Southeast

consisted of mast producing hardwood forests (Healy 1981). The value of the

range increased as both the proportion of hardwood forest and the percent in

mast production increased. Trees that may provide fall and winter foods for

the eastern wild turkey include oaks, dogwoods, beech, gums, ash (Fraxinus

spp.), pecans and hickories (Carya spp.), pines, cherries, sumacs (Rhus spp.),

and hawthorn (Crataegus spp.) (Korschgen 1967). ----

Early winter foods in Virginia included grapes (Vitis spp.), acorns, corn

(Zea mays), dogwood fruits, grass blades, and ash seeds (Martin et al. 1939).

Frui t i ng shrubs provi ded over 10% of the wi nter di et of the eastern wi 1d

turkey (Korschgen 1967). Waste grain was an important winter food in Missouri

(Ellis and Lewis 1967). Turkeys in the Upper Missouri Valley made extensive

use of corn fields located adjacent to hardwood stands (Porter et al. 1980).

Areas 1ack i ng corn experi enced a 60% loss of turkeys duri ng severe wi nters,

whereas those with available corn had losses of less than 15%. Corn, oats

(Avena sativa), and wheat are the primary cultivated grains consumed by turkeys

(Korschgen 1967). Corn is highly digestible, whereas oats are less digestible

by wild turkeys (Glover and Bailey 1949). Soybeans (Glycine max) are a highly

preferred food in Missouri (J. B. Lewis, Missouri Departmentof Conservation,

Columbia; letter dated November 8, 1984).

Croplands played a major role in maintaining turkey populations in

northern Missouri (Lewis and Kurzejeski 1984). Cropfields without adjacent

stands of mature timber were seldom used. Furthermore, regardless of the

amount of adjacent mature timber, croplands were used much less when acorns

were abundant. Thi s suggests that crops may be a secondary food source.

Wi nteri ng turkeys in Mi nnesota fed on ei ther acorns in hardwood forests or

corn dependi ng on the abundance of these two major food resources (Porter

1978). Hardwood habitats were important, but agricultural areas provided the

reliable and abundant food supplies needed to maintain turkey populations.

Turkeys also eat tubers, bulbs, rhizomes, earthworms, millipedes, spiders,

snails, and salamanders hidden within and below the layer of leaves and organic

matter on the ground (Bailey and Rinnell 1968). These food items are available

year round, except during periods of deep snow or frozen ground.

Water

Water is an essential factor in good turkey range. Turkeys in the eastern

United States can easily obtain water year-round from streams, ponds, seeps,

3
or depressions in the ground (Korschgen 1967). Water was apparently not

required in early brood ranges in the mountains of the Southeast, because hens

and broods could obtain adequate amounts of water from their food (Healy

1981). The presence of a free water source also was not an important factor

in brood habitat selection in Minnesota (Porter 1980).

Cover

Wi ld turkeys use forested habitats for cover throughout the year, and

spend a large amount of time loafing and feeding in open areas (Porter,

unpub 1.). A mi xture of forests and open 1ands may provide habi tat that is

equal or superior to extensive forested areas (Little 1980; Hecklau et al.

1982). Turkeys appear to prefer woodlands that are open and mature (Lindzey

1967; Markley 1967), possibly because such habitats allow the turkey to use

its keen eyesight to detect predators and increase its chances for escape and

survival (Lindzey 1967). Dense, brushy areas are used for escape cover, but

such areas are not preferred for normal activities. Favored travel areas in a

Georgia study had scant ground cover and good eye-level visibility (Eichholz

and Marchinton 1976). Areas with dense briars or saplings were not used for

travel. Forested stands composed of one or only a few tree species (especially

conifers) provide poor turkey habitat (Bailey and Rinnell 1968). Preferred

foraging cover for hens with young consists of fields or open forests where

the herbaceous vegetation is high enough to provide concealment and sparse

enough to allow easy movement.

Ideal turkey range in Alabama was described as follows by Davis (1976:22):

lilt is generally agreed that ideal wild turkey range in Alabama

consists of a minimum of 5,000 acres of a multi-aged, mixed, pinehardwood forest, interspersed with ample meadow or grassy openings.

Ideal range should also have a relatively open understory, consisting of shrubs, vines, saplings and small trees, a high percentage

of which are dogwood and other food-producing types such as plums,

mayhaws, and muscadines. Openings may account for as much as 25-30

percent of the total acreage, provided these are several in number

and are well di stributed throughout the forested habitat. Ideal

range is well watered with springs, small streams, ponds, or rivers

and consists of the usual mixture of hardwood forest tree species,

including a number of different kinds of oaks ."

Habitats providing poor turkey range include large acreages of even-aged,

short rotation pine plantations, intensive agricultural areas (particularly

row crops), and areas with either dense human populations or high levels of

human activity (Davis 1976).

Winter was a time of stress for wild turkeys in Vermont, and some flocks

that normally wintered in northern hardwoods sought dense conifers during

periods of extreme cold (Bortner and Bennett 1980). Winter roost sites in

Pennsylvania were not different from adjacent forest stands, and forests with

a balance of age classes that provide adequate food would likely provide

adequate winter roost sites (Tzilkowski 1971).

4
Turkeys in southeastern Mi nnesota had di ffi cu1 ty movi ng in snow that

exceeded 25.0 cm in depth (Porter 1977), and prolonged periods of deep snow in

this region can be a limiting factor for turkeys (Porter et a1. 1980). Severe

wi nter weather with deep snows and a poor food supply caused hi gh wi nter

mortality of turkeys in West Virginia (Glover 1948). Although snow may cause

some mortality, the highest turkey populations and largest broods in West

Vi rgi ni a often occurred in areas that recei ved the greatest snowfall (Bail ey

and Rinne11 1968). Turkeys in another West Virginia study area tended to seek

areas with the least amount of snow, for ease of feeding (Healy 1977). Feeding

sites in cherry (Prunus spp.)-map1e (Acer spp.) forests were characterized by

seeps, southern exposures, and sawtimber stands with a high proportion of wild

cherry.

Turkeys in the Upper Mississippi Valley were frequently restricted by

snow in winter to less than 10% of their normal range (Porter et al. 1980).

Spring seeps, important winter food source areas in the eastern United States,

are uncommon in the Upper Mississippi Valley and mast production is often

poor. Areas with corn available through winter tended to provide enough high

quality food to mitigate the effects of severe winters.

Turkey dusting sites are frequently in the dry residue of rotted logs, ant

hills, newly tilled soils, or other bare soil areas (Bailey and Rinne11 1968).

Reproduction

Turkeys nest on the ground in areas concealed by fairly dense brush,

vines, deep grass, or fallen tree tops (Williams 1981). Hay fields, fence

rows, and utility rights-of-way provide important nest sites in densely

forested areas. Nests in the Southeast were found mostly in or near openings

(Hillestad 1973; Speake et a1. 1975), and large forested areas lacking openings

provided poor nesting habitats (Davis 1976).

Thirty-seven percent of the nests in an Alabama study were on power line

rights-of-way, although this cover type comprised only 0.6% of the study area

(Everett 1982). Turkeys avoided nesting in the rights-of-way when the average

vegetation height was less than 25.0 cm during the first year these areas were

mowed. Nests were placed in the rights-of-way in the second and third years

after mowing, when the vegetation consisted of mixed herbaceous growth and low

shrubs with heights from 1 to 2 m. Such vegetation conditions were preferred

nest sites wherever they occurred, and provided 73% of all nest sites located

in the study area.

Vegetation around nests in the mountains of the Southeast usually provided

hens with a wide view of the surroundings, yet still provided concealing cover

(Healy 1981). Ground cover less than 25.0 cm tall was usually sparse, while

cover 25.0 to 50.0 cm tall was provided by brush, vines, slash or fallen logs.

Woody understory greater than 50.0 cm tall and 1ess than 2.5 cm dbh was

frequently moderately dense. Preferred foraging cover for hens with young

appears to be that which is tall enough to conceal the young for the six weeks

after hatching, but short enough to allow females enough visibility to detect

distant predators (Porter, unpubl.). Healy (1981) concluded that all common

forest types in the Southeast could provide suitable nesting habitat.

5
Striped skunks (Mephitis mephitis), raccoons (Procyon lotor), and opossums

(Didelphis marsupia1is) accounted for approximately two-thirds of nest predation in Alabama (Davis 1976). Logging, mowing, or haying may cause nest

abandonment, or may cri pp1e or kill the hen. I n another Alabama study,

raccoons, feral dogs, and opossums were the three most significant nest

predators (Speake 1980).

The essential feature of turkey brood habitat is adequate herbaceous

vegetation (Healy and Nenno 1983), and the lack of high quality brood rearing

habitat may be a 1imiting factor for turkeys in some areas (Hillestad and

Speake 1970). The presence of high quality brood rearing habitat increases

the rate of turkey poult survi va1 (Davi s 1976). In an Alabama study area,

only 2% of the forest habitat contained openings, and it appeared that this

absence of adequate brood range was a limiting factor for this turkey population (Everett 1982).

Broods in West Virginia preferred forest understories with abundant

herbaceous growth and avoi ded stands with a dense woody understory (Pybus

1977). Broods preferred forests with basal areas between 9 and 18 m2/ha and

avoided forests with basal areas exceeding 23 m2/ha (Pack et a1. 1980).

Coniferous forest types received little or no brood use.

Early brood range in the mountainous regions of the Southeast is characteri zed by abundant, low growi ng herbaceous cover, wi th few overstory trees

(Healy 1981). The biomass of herbaceous vegetation is more important than the

species composition. Sparse herbaceous understories, 9.0 to 23.0 cm tall and

100 to 460 kg/ha dry weight, typi ca1 of many oak forests, di d not provi de

enough seeds or insects for pou1 t feedi ng. Lush orchardgrass (Dactyl i s

glomerata) stands, 78.0 cm tall and 3,380 kg/ha dry weight, provided an

abundance of insects, but were too dense for foraging poults to move through.

Healy (1978) estimated that the best habitat for young broods in the

Southeast consisted of a complete cover of forbs and grasses, 40.0 to 70.0 cm

tall, with a biomass of 600 to 3,000 kg/ha dry weight. This vegetation

structure provides food for both hens and poults, cover for poults, and allows

hens to see over the top of the vegetation while remaining concealed. This

type of vegetation is abundant in fields, and also occurs in mesic forests.

Interspersion of trees and openings allows broods to escape predators and to

select a suitable microclimate within a short distance. As an alternative to

biomass measurements, Healy (W. M. Healy, U.S. Forest Service, Ho1dworth Hall,

University of Massachusetts, Amherst; pers. comm.) recommended the following

to describe ideal early brood range: (1) 60 to 100% total vegetative cover

(woody and herbaceous) in the understory; (2) vegetation heights from 20.0 to

60.0 cm; and (3) at least one-half the vegetation comprised of herbaceous

growth.

Forest clearings should be managed for young poults (less than one month

old) due to the poults' high mortality rates, small home ranges, specialized

food habits, and narrow habitat requirements compared to older poults and

adults (Healy and Nenno 1983). Brood range for older poults can be provided

by a 1arger vari ety of habitat types. 01 der poults can utili ze most forest

openings, including those that were too dense for young poults (Healy 1981).

6
Good brood habitat in Mississippi was thought to consist of poorly managed

(unimproved) pastures (Owen 1976 cited by Hurst 1978) which provided an abundance of insect and plant food, and cover in the form of clumps of woody

vegetation (Hurst 1978). Savannah-like old fields appear to provide better

habitat for turkey poults than intensively managed agricultural clearings

(Nenno and Lindzey 1979). The benefits of the savannah-like fields include:

(1) an increased vari ety of invertebrate foods; (2) a greater vari ety and

abundance of plant foods; (3) a vegetation structure that allows easier poult

movements; (4) favorable microclimates; (5) increased edge; and (6) protection

provided by the partial canopy cover. Tree canopy cover ranging from 30 to

60% allows for adequate herbaceous growth, and is a preferred brood habitat.

Females with broods in Minnesota spent as much as half of their daytime

hours in crop and hay fields (Porter 1978). Corn fields provided loafing and

escape cover for hens, whereas broods spent most of their time in alfalfa

fields.

Reclaimed surface mines in Pennsylvania can provide useful brood habitat,

depending on vegetation density and corresponding insect abundance (Anderson

and Samuel 1980). Grain drill planting of cover crops in such areas provided

greater mobility for poults than hydroseeding which resulted in matted vegetation. Poults used the row spaces in grain drilled areas for stalking invertebrates. The poults also had less contact with morning dew in these areas,

which reduced the amount of required brood time with the hen.

Interspersion and Composition

An interspersion of grassy, permanent forest openings, along with the

edges they create, enhances brood production of turkeys (81 ackburn et a1.

1975). Different authors have reported varying requirements for the percentage

of openings needed for good wild turkey range. Latham (1958) stated that at

least 10% of the total range should be in openings for satisfactory populations, and that clearings should be spaced so a hen need not travel more than

1.6 to 3.2 km to find one. Speake et al. (1975) recommended that spring and

summer turkey habitat in the Southeast should include 12 to 25% of the area in

well-di spersed openi ngs. Poults ina Mi nnesota study area used about 29.0 ha

for a weekly brood range (Porter 1980). Four or five such blocks of optimal

brood habitat per 10.0 km", or 1.8 km radius, appeared to satisfy summer

habitat needs of broods. This corresponds to a habitat with 11.6 to 14.5% of

the area meeting brood needs.

The interspersion of hardwood forests and agricultural lands is an

important feature in providing favorable turkey habitat in the Upper Midwest

(Porter 1978). Thriving turkey populations exist in Missouri in areas of 50%

forest cover, with well-interspersed open land and alternate winter foods for

times of low mast production (Ellis and Lewis 1967). Lewis and Kurzejeski

(1984) suggested that optimal habitat in Missouri is approached in areas with

a 50:50 mix of mast-producing forests and open lands. Of the 50% open lands,

they suggested that at least 20% should be row crops, 45% pasture, and 25% old

fields. Recent studies of turkeys in Iowa also have suggested that a 50:50

ratio of forests to open lands is better than extensive forests (Little 1980).

7
Iowa has reintroduced turkeys into such areas and subsequent population

densities are among the highest reported for the eastern wild turkey. Few

forest stands in these areas exceed 400 ha in size, and most are smaller and

scattered. The area has abundant edge between forest 1ands and crop and

pasturelands, which provides access to insects for broods and waste grain for

winter food. Turkeys also occur on dairy lands in New York where most woodlots

are less than 101 ha in size (Bailey and Rinnell 1968). Turkeys in a Minnesota

study survived and reproduced in areas with as little as 12% forest cover

(Hecklau et al. 1982).

Turkeys did not readily use the centers of 12.2 to 24.3 ha fields in

Tennessee and Michigan, unless a peninsula of trees penetrated the field to

provide travel cover (Lewis 1964). Turkeys in Virginia were not observed in

the interior of a 24.3 ha clearcut, although they did use the edges (Raybourne

1968). Turkeys crossed clearcuts less than 137 to 183 m in width, but only

traveled 46 to 69 minto clearcuts greater than 274 m in width. Clearcuts

greater than 183 m in width may restrict turkey movements to the edge of the

area.

The annual and seasonal range sizes of wild turkeys are related to habitat

quality (Everett 1982). Turkeys on poor ranges must move greater distances to

meet their needs than turkeys on better quality habitat. Turkey range sizes

and movements are di ctated by the food supply (Korschgen 1967). The annua1

ranges of males and females in Missouri were 448 ha and 553 ha, respectively

(Ellis and Lewis 1967). In Alabama, male turkeys had an annual range of

1,631 ha, and females had an annual range of 1,439 ha (Everett 1982). Average

seasonal range sizes in the Southeast were smallest for hens with broods

(111 ha) and largest for hens in the fall and winter (430 ha) (Speake et al.

1975). Winter ranges of most turkeys in a Minnesota study were less than

25 ha due to the restri ctions caused by snow cover (Porter 1977). Speake

et al. (1969) estimated that the requirements of a self-sustaining population

of turkeys could probably be met in an area of 3,240 to 4,050 ha. Lewis and

Kurzejeski (1984) suggested that a minimum of 750 ha of habitat is required in

Missouri to insure high turkey population densities. Turkeys were introduced

into Presque Isle State Park in Pennsylvania, which has a high level of human

use (Wunz 1971). Turkeys restri cted thei r movements to 81 ha of very dense

understory. Wunz (1971) concluded that as little as 203 ha may be adequate

for establishing turkeys in forested areas with dense human populations.

In New York, hens (older than 1 year) moved an average of 5.5 km from

winter range to nest sites, and an average of 1.9 km from nest sites to broodrearing areas (Eaton et al. 1976). Large improved pastures, roads, and large

cropland clearings acted as barriers to turkey movements in Georgia (Eichholz

and Marchinton 1976).

Special Considerations

Wild turkeys have a low tolerance of continuous and varied human activities (Davis 1976). Turkey populations may decline due to habitat losses

associated with urbanization, highway and reservoir construction, expanded row

crop farming, and conversion of large areas to short rotation, even-aged, pure

8
pine plantations. Turkey abundance usually is inversely correlated with human

abundance (Bailey and Rinnell 1968). However, there is a wide variation in

wariness of humans among different turkey populations, depending on hunting

pressure and other disturbance level s (Wright and Speake 1975). Humans are

less of a disturbance factor where turkey hunting does not occur (Bailey and

Rinnell 1968). Turkey populations in Louisiana were significantly lower in

areas where it was believed that poaching was a problem (Dickson et al. 1978).

Human densities in Minnesota as high as 15 people/km2 did not appear to affect

survi va1 and reproduction of transplanted turkeys duri ng thei r fi rst year

(Hecklau et al. 1982).

Turkeys in a Kentucky study avoided a large area that was used by off-road

vehicles (Wright and Speake 1975). Turkeys also avoided areas within 1,000 m

of a new foot trail which was used by about 125 people/week, whereas similar

adjacent habitats without trails were consistently used by turkeys. Areas

within 1,000 m of a campground also were avoided by foraging turkeys. Turkeys

tolerated routine agricultural operations and were seen feeding in a large

field where a tractor was working at a distance of 500 m.

Forestry practices exert a strong i nfl uence on turkey numbers (Markley

1967). Extensive clear-cutting may make areas unsuitable for turkeys. Hardwood removal and conversion to short rotation pine plantations also have a

negative effect on turkeys.

Controlled burning of forests in the Southeast may be used to produce a

greater abundance and diversity of accessible food items (Davis 1976). Burned

tracts of loblolly pine (P. taeda) - shortleaf pine (P. echinata) forest

provided either more insects or more available insects than areas that were

not burned for 4 years (Hurst 1978). Burned areas were more open and allowed

ease of movement for poults. Unburned areas (s 3 years since burning) provided

nest habitat, escape, and brood cover, and an abundance of dewberries (Rubus

trivialis). However, both burned and unburned tracts in this forest type were

not as good for brood habitat as pastures and fields.

HABITAT SUITABILITY INDEX (HSI) MODEL

Model Applicability

Geographi c area. This model was developed for app1i cati on wi thi n the

entire range of the eastern wild turkey. Current range maps for the eastern

wild turkey were not found in the literature. Users near the periphery of the

range of the eastern wild turkey should consult local authorities to confirm

the appropriateness of applying this model.

Season. This model was developed to evaluate the year round habitat

needs of the eastern wild turkey.

9
Cover types. This model was developed to evaluate habitat qual ity in

Deciduous Forested Wetland (DFW), Evergreen Forest (EF), Deciduous Forest

(OF), Evergreen Tree Savanna (ETS), Deci duous Tree Savanna (DTS), Evergreen

Shrubland (ES), Deciduous Shrubland (OS), Evergreen Shrub Savanna (ESS),

Deciduous Shrub Savanna (DSS), Grassland (G), Forbland (F), Pasture and Hayland

(P/H), and Cropland (C) areas (terminology follows that of U.S. Fish and

Wildlife Service 1981).

Minimum habitat area. Minimum habitat area is defined as the minimum

amount of contiguous habitat that is required before a species will occupy an

area. Based on annual range sizes reported in the literature, it is assumed

that a minimum of 900 ha of habitat must exi st or the HSI for eastern wi ld

turkeys will equal zero.

Verification level. This model represents several hypotheses of

species-habitat relationships and does not reflect proven cause and effect

relationships. Previous drafts of this model were reviewed by William M.

Healy, U.S. Forest Service, Northeastern Forest Experiment Station, Amherst,

MA; George A. Hurst, Dept. of Wildlife and Fisheries, Mississippi State

University, Mississippi State; John B. Lewis, Missouri Dept. of Conservation,

Columbia; Terry W. Little, Iowa Conservation Commission, Des Moines; William E.

Porter, State University of New York, Newcomb Campus, Newcomb; and Dan W.

Speake, Alabama Cooperative Wildlife Research Unit, Auburn. Improvements and

modifi cations suggested by these revi ewers have been incorporated into thi s

model, and are cited as personal communications, where appropriate.

Model Description

Overview. The year-round habitat needs of eastern wi ld turkeys can be

provi ded by a vari ety of di fferent cover types. The summer food and brood

habitat requirements are provided in areas containing herbaceous vegetation of

the proper height and density, in proximity to protective woody cover. Such

areas provide abundant insect and plant foods for poults and adequate cover

for hens with poults. Coniferous cover types are generally avoided during the

summer.

Habitats with a variety of food sources provide potentially optimum food

values during fall, winter, and spring. Eastern wild turkeys prefer areas

with a diversity of food-producing trees and shrubs. Agricultural crops,

especially corn and soybeans, also provide an important winter food source.

The cover needs of the adult turkey are provided in mature hardwood

forests with relatively open understories. It is assumed that nest sites will

be present if food and cover are adequate, and that water will not be a limiting factor due to its widespread availability throughout the range of the

eastern wild turkey. The following sections provide written documentation of

the 1ogi c and assumptions used to interpret the habi tat i nformat i on for the

eastern wild turkey in order to explain the variables that are used in the HSI

model. Specifically, these sections identify important habitat variables,

describe suitability levels of the variables, and describe the relationships

between variables.

10
Summer food/brood habitat component. The major summer food and brood

needs are insect food and cover for young poults. It is assumed that summer

food and brood habitat needs may be provided in all cover types except evergreen forests, evergreen shrub1ands, and crop 1ands. A measurement of the

structure of herbaceous vegetation is assumed to be an adequate indicator of

the qual ity of insect food and cover resources. The amount of biomass of

herbaceous vegetation is more important than the species composition (Healy

1981). The optimum structure of herbaceous vegetation is assumed to occur

when plant height and density provide the maximum amount of vegetative biomass

(i .e., potential insects) without restricting the movements of young poults.

This level is assumed to occur when the herbaceous canopy cover is between 60

and 80%. Suitability is assumed to decrease to a moderate level in areas with

100% herbaceous cover due to the restrictions in poult movement caused by the

extremely dense cover. It is assumed that areas with less than 20% herbaceous

canopy cover will be too sparse to provide adequate food or cover for poults.

The relationship between herbaceous canopy cover and a suitability index

(SIV1) for the eastern wild turkey is presented in Figure 1a.

Optimum herbaceous canopy height occurs where the vegetation is high

enough to provide concealment for the hen, but low enough to permit the hen to

see the surrounding habitat. It is assumed that optimum herbaceous height

occurs between 20.0 and 60.0 cm. Suitability is assumed to decrease to zero

as heights increase to 100.0 cm, due to the inability of hens to view their

surroundi ngs in such areas. Vegetation 1ess than 5 cm is assumed to be too

short to provide cover. The relationship between herbaceous canopy height and

a suitability index (SIV2) for the eastern wild turkey is presented in

Figure lb.

An index for summer food/brood habitat suitability (FBSI1) is computed by

combining the indices for density and height of herbaceous vegetation (SIV1

and SIV2, respectively). A habitat with very low herbaceous heights and a

very sparse canopy cover of herbaceous vegetation would provide more food and

cover for turkeys if either the height or density of herbaceous vegetation was

increased to a higher suitability level; i.e., there is a compensatory

relationship between the variables. It is further assumed that when herbaceous height and density are present at the same levels of suitability, the

habi tat va1ue for the summer food/brood habi tat component wi 11 be equa1 to

that level of sut t abt l l ty . This relationship applies to specific forest and

tree savanna cover types (OFW, OF, ETS, and OTS) and can be expressed mathematically as shown in Equation 1.

FBSI1 =(SIV1 x SIV2)1/2

11

(1)
Fig. 1a Fig. 1b

1.0 1.0 ..--l N

::::- ::::- ...... ...... VI 0.8 VI 0.8

x x Q) 0.6 Q)

"0 "0 0.6 s::: s::: ...... ......

>, 0.4 >, oj-) oj-) 0.4 - ...... ......

......

..0 0.2 ..0

co co 0.2

+-' +-' ...... ......

VI 0.0 VI 0.0

0 25 50 75 100 0 50 100+ cm

Percent herbaceous canopy 0 19.7 39.4+ inches

cover Average height of herbaceous

canopy (summer)

Distance to forest or tree

savanna cover types

Figure 1. The relationships between habitat variables used to evaluate

summer food and brood habitat and the suitability indices for the

variables.

12
The suitability of herbaceous vegetation for hens and broods is affected

by the proximity of forest cover that can be used for escape and protection.

It is assumed that escape cover will not be a limiting factor in forested or

tree savanna cover types. I n herbaceous domi nated cover types (e. g., grassland, forbland, and pasture and hayland), it is assumed that optimum suitabilities will exist when a tree dominated cover type is within 61 m. It also is

assumed that herbaceous areas more than 122 m from forest cover wi 11 not be

used by turkeys. These estimates are based on data from Lewis (1964) and

Raybourne (1968) on turkey use of openings. Turkeys will move greater

distances away from forest cover in cover types that provide overhead cover

(Porter, unpubl.). It is assumed that in shrub dominated cover types

(shrublands and shrub savannas) optimum suitabilities will exist when a tree

dominated cover type is within 100 m, and that shrub dominated areas farther

than 400 m from forest cover will be unsuitable. The relationships between

the distances from herbaceous or shrub cover types and a suitability index are

presented in Figure 1c.

The value of the summer food/brood habitat component (FBSI2) in specific

shrub and herbaceous dominated cover types is equal to the value determined

for herbaceous height and density, directly modified by the value related to

the proximity of forest cover. The suitability of the herbaceous growth in

such areas will be directlY lowered as the distance to forest cover increases.

Tllfs re!at fonsllfp applies to specific shrub end nerbeceous cover types (aS,

ESS, DSS, G, F, and P/H) and can be expressed mathematically as shown in

Equation 2.

FBSI2 = (SIV1 x SIV2)1/2 x SIV3 ( 2)

Fall/winter/spring food component. Eastern wild turkeys are omnivorous

opportunists (Bailey and Rinnell 1968) and the best management would provide a

diversity of habitats within their annual range (Korschgen 1973). Fall,

winter, and spring foods are provided in forests, shrublands, and croplands

and include hard mast, seeds, and soft mast produced by trees and shrubs, as

well as agricultural crops, especially corn or soybeans. Acorns are an

important food source in many areas, but are not essential, because other

trees may provide alternate foods. The specific trees used as food sources

will vary across the range of the eastern wild turkey. Food producing species

include, but are not limited to, oaks, dogwoods, beech, gums, ash, pecans,

hickories, pines, wild cherry, hackberry, sumac, and hawthorn.

For purposes of this model, hard mast trees are assumed to include species

such as oaks, hickories, pecan, beech, and pine. Soft mast trees include

species such as gums, ash, wild cherry, hackberry, sumac, and hawthorn. For

specific applications of this model, it is suggested that users define a list

of both hard and soft mast producing trees for the particular geographic

region of the application.

13
The amount of acorn mast produced in a forest varies from year to year,

from species to species, and from tree to tree of the same species (Shaw

1971). The number of acorns produced per tree increases in a linear relationship with increased tree diameter (Goodrum et al. 1971; Shaw 1971). Although

acorn production is positively correlated with individual tree diameters,

overall acorn production in forest stands is influenced by canopy conditions

and shading. Shaded trees produce less mast than trees grown in open s~ands.

The exact structural forest conditions that must exist to maximize hard mast

production have not been reported in the literature.

McQuilkin and Musbach (1977) conducted a 14-year study of pin oak (Q.

pa 1ustri s) acorn product i on on both fl ooded and unflooded sites in Mi ssouri .

Their data indicated that mast production on plots with trees mostly 27.9 cm

dbh or larger was 85% higher than on plots with most trees less than 25.4 cm

dbh. On nonflooded plots, which would be most representative of typical

turkey habitat, there were no statistically significant differences in acorn

production on plots with low, medium, or high stocking rates. Low stocking

rate plots had basal areas of 9.2 m2/ha, medium plots had basal areas of

13.8 m2/ha, and high plots had basal areas of 17.2 to 20.7 m2/ha.

The low stocking rate in McQuilkin and Musbach's (1977) study is about

equal to the lower 1imits of upland hardwood stands that are termed understocked by the U.S. Forest Service (Gingrich 1971). The stocking chart from

Gingrich (1971:66) was used to estimate the minimum numbers of trees of

specific size classes that are required to reach the lower limit of understocked stands. It is assumed that forests with tree densities below this

level will show reduced hard mast production. Using the stocking chart, it

can be determi ned that, for 25.4 cm di ameter trees, 235 or more trees per ha

are needed to be at the lower limit of understocked stands. For trees 38.1 cm

in diameter, 124 or more are needed per ha to reach the minimum stocking

level. The relationships between the number of trees of various diameter

classes and suitability indices (SIV4) for the eastern wild turkey are shown

in Fi gure 2a. It shoul d be noted that SIV4 is compri sed of two measured

habi tat vari abl es: average dbh of hard mast trees that are greater than

25.4 cm dbh; and number of hard mast trees/ha that are greater than 25.4 cm

dbh.

It is assumed that total forest hard mast production will not increase at

tree densities above those shown as maximum in Figure 2a. This is based on

the assumption that although there wi 11 be more trees in such stands, the

amount of mast produced per tree wi 11 be lower due to shadi ng and, thus,

overall mast production will be the same. This assumption is supported by the

study of McQuilken and Musbach (1977), which showed no difference in acorn

production at low, medium, and high stocking conditions. Although the preceding mast relationships were developed using data from oaks, it is assumed that

the basic relationships will apply to all trees that produce hard mast.

In general, soft mast produci ng trees begi n to produce mast at small er

tree di ameters than hard mast trees. Therefore, it is assumed that a measure

of dbh is not needed for soft mast trees. A measurement of tree canopy closure

of soft mast trees is assumed to provide an indirect measure of food abundance.

14
Fig. 2a Fig. 2b

A BC 0 E F

1.0 Average DBH 1.0

q- L(")

:> A= 38.1+ em :> ....... ....... V> 0.8 B= 35.6+ em V> 0.8

x C= 33.0+ em x Q) 0= 30.5+ em Q)

"'0 0.6 "'0 I:: 0.6 E= 27.9+ em I:: ....... .......

>, F= 25.4+ em >, +J 0.4 +J 0.4

..0 ..0 n:::l 0.2 n:::l 0.2 +J +J

V> V> 0.0 0.0

0 50 100 150 200 250 0 25 50 75 100

Number of hard mast producing Percent canopy closure of

trees/ha that are >25.4 em soft mast producing trees

dbh (average dbh values should

only consider hard mast trees

that are >25.4 em dbh)

Figure 2. The relationship between habitat variables used to assess

the fall, winter, and spring food value of trees and suitability

indices for the eastern wild turkey.

Optimum forested habitats are assumed to contain 40% or greater tree canopy

closure of soft mast producing trees. It is further assumed that overall soft

mast production will not increase as canopy closures exceed 40%, due to the

increase in shading and lower production per tree in such areas. The relationship between the percent tree canopy closure of soft mast producing trees and

a suitability index (SIV5) for the eastern wild turkey is presented in

Figure 2b. It is assumed that either soft or hard mast, or a combination of

the two, may provide optimum overall mast conditions for the eastern wild

turkey.

Shrubs also may contribute to the fall, winter, and spring food value. A

dense layer of shrubs would provide abundant wild turkey food; however, turkey

access and movements would be restricted in such areas due to the poor visibility and vulnerability of turkeys to predation. It is assumed that optimum

shrub dens iti es for food production occur at shrub crown covers of 20% or

more. Areas with no shrubs will contribute nothing to shrub food production.

The relationship between shrub cover for food production and a suitability

index (SIV6) is presented in Figure 3a. It is further assumed that shrub

densities of less than 40% crown cover will not restrict wild turkey use of an

area. As shrub cover exceeds 40%, it is assumed wil d turkeys will show

decreased use of the area, regardless of the amount of food production from

trees and/or shrubs, due to a behavi ora 1 response to the dense shrub cover.

15
Fig. 3a Fig. 3b

1.0 1.0 \D r-,

:::- :::- ..... ..... (/') 0.8 (/')

.......... 0.8

x x

Q) Q)

"'0 0.6 "'0 t: t: 0.6 ..... .....

>, >, ..... 0.4 0.4 ..... .....

..... ..... ..c 0.2 ..c n::l n::l 0.2 ..... ..... ..... ..... :::l :::l

(/') 0.0 (/') 0.0

0 25 50 75 100 0 25 50 75 100

Percent shrub crown cover Percent shrub (food production) crown cover

(behavioral)

Fig. 3c

co 1.0 :::-

.....

(/')

.......... 0.8

x

Q)

"'0

t: 0.6 .....

>,

.....

..... 0.4 .....

..c

n::l 0.2 .....

.....

:::l

(/') 0.0

0 25 50 75 100

Percent of shrub crown cover

comprised of soft mast

producing shrubs

Figure 3. The relationship between habitat variables used to assess

the fall, winter, and spring food value of shrubs and sUitability

indices for the eastern wild turkey.

16
Areas with shrub coverage of 80% or greater are assumed to be totally unsuitable for turkeys. The relationship between shrub cover related to the turkey's

behavioral response and a suitability index (SIV7) is presented in Figure 3b.

It is assumed that the best shrub conditions exist when 100% of the shrubs

produce soft mast, and that low suitabilities will still be provided in areas

with a lack of soft fruit producing shrubs, due to the turkey's use of other

shrub plant parts for food. The relationship between the amount of soft fruit

producing shrubs and a suitability index (SIV8) is presented in Figure 3c.

The fa 11, wi nter, spri ng food value (FWSSIl) in forest and tree savanna

cover types is equal to the combined values of tree and shrub mast, modified

by overall shrub density. Tree mast may be provided by either soft or hard

mast species, and it is assumed that tree mast and shrub mast are equal in

value. Excessive shrub densities will detract from the value of all mast

resources. These relationships can be expressed mathematically, as shown in

Equation 3, for DFW, EF, DF, ETS, and DTS.

FWSSII = (SIV4 + SIV5) + (SIV6 x SIV8)

2 x SIV7 (3)

Note: When the sum of SIV4 + SIV5 exceeds 1.0, it

should be reduced to 1.0 before computing FWSSI1.

The fall, winter, spring food value (FWSSI2) in shrub cover types is

equal to the amount of food producing shrubs, modified by overall shrub density

and the distance to forest cover. Shrubs alone are assumed to be able to

provide up to one-half of the total fall, winter, and spring food value. This

relationship can be expressed mathematically, as shown in Equation 4, for ES,

DS, ESS, and DSS.

FWSSI2 =(SIV6 x SIV8) x SIV7 x SIV3

2 (4)

Croplands may provide high quality fall, winter, and spring food for the

eastern wild turkey, especially in the western and northern portions of the

turkey's range. Corn and soybeans are highly preferred, while other grains

are somewhat less valuable food sources. Crops other than corn, soybeans, and

other grains are assumed to provide no food value. The relationship of the

type of crop to a suitability index (SIV9) is presented in Figure 4a. The

overwinter management of croplands will have a significant effect on the

amount of crop food potentially available to turkeys. A direct measure of

waste crop availability requires considerable field time and there is a large

amount of variability in such measurements (Frederick et al. 1984). Therefore,

a general approach is taken in this model to assess overwinter crop availability. Optimum conditions are assumed to exist in areas where more than 5% of

the crop remains unharvested through the winter. Areas with the crop harvested

17
in the fall, but plowed in the spring, will have moderate suitability. Croplands with a fall harvest and fall plowing will have no SUitability, due to

the lack of waste crops. The relationship between the overwinter management

of croplands and a suitability index (SIVI0) is presented in Figure 4b. The

objective in assessing croplands is to determine the actual amount of waste

grain available. Users with specific information on waste grain abundance may

wish to revise these variables to fit their local data. An additional factor

affecting the useability of croplands is the proximity to forest cover. This

relationship in croplands is assumed to be the same as that described for

herbaceous cover types in Figure lc for summer food/brood habitat. The overall

fall, winter, spring food value (FWSSI3) in croplands is equal to the value

for the type of crop, directly modified by the type of overwinter management

and distance to forest cover. This relationship can be expressed mathematically, as shown in Equation 5, for croplands.

O"l 1.0 ::-

......

(/) 0.8 x

QJ

"C

c: 0.6 ......

0.4

.....

.0

of...>

<0 0.2 .....

(/)

0.0

FWSSI3 = SIV9 x SIVI0 x SIV3

Fig. 4a

f-

- '-

ABC

Type of crop

A) corn or soybeans

B) other gra ins

C) other crops

Figure 4. The relationships between habitat variables used to assess

the fall, winter, and spring food value of crops and suitability

indices for the eastern wild turkey.

18

(5 )
Cover component. The cover needs of the eastern wild turkey are provided

by mature deciduous, and mature mixed evergreen and deciduous, forests.

Turkeys prefer forests with mostly open understories, and understory density

is considered in this model by the shrub cover variables in the fall, winter,

spring food component. It is assumed that roost sites will be adequate in

areas that provide cover, as described in the following paragraphs.

Thi s model assumes that optimum cover condi t ions for the eastern wi 1d

turkey exist in areas with 50% tree canopy cover..Habitats with less than

10% tree canopy cover are assumed to be unsuitable for turkeys because of the

small amount of cover they will provide. The relationship between tree canopy

cover and a suitability index (SIV11) for the eastern wild turkey is presented

in Figure Sa. It shoul d be noted that the di stri buti on and i nterspersion' of

forest cover is assessed by the variable presented in Figure 1c.

Eastern wild turkeys prefer mature or old growth forests due to both the

structural characteristics and food production in such habitats. Sapling

forests provide poor overhead cover and are frequently too dense at ground

1eve 1 for turkeys. The di ameter of overstory trees provides an i ndi rect

assessment of forest maturity, and it is assumed that optimal habitats contain

overstory trees that average 30.5 cm dbh (Lewis, unpubl.). All trees are

assumed to have some value for eastern wil d turkeys; however, suitabil i ty is

assumed to decrease to a very low level as the average size of overstory trees

decreases to 12.7 cm dbh or less (Lewis, unpubl.). The relationship between

overstory tree diameter and a suitability index (SIV12) for the eastern wild

turkey is presented in Figure 5b.

Turkeys utilize both deciduous and evergreen forests, but deciduous

forest types are preferred. It is assumed that habitats with less than 30% of

the canopy comprised of evergreens will be optimal. Forests that are entirely

evergreen will have low suitability for eastern wild turkeys. The relationship

between the amount of evergreens in the tree canopy and a sui tabi 1i ty index

(SIV13) for the eastern wild turkey is presented in Figure 5c. A total lack

of evergreen trees in the northern portions of the range of the eastern wild

turkey may indicate less than optimum suitabilities, especially during severe

winters when conifers are used for cover. Users in these geographic areas

should consider this possibility prior to applying this model.

The overall cover value (CSI) for eastern wild turkeys in forested cover

types is a function of tree canopy closure, the percent evergreen trees, and

forest maturity (i.e., dbh). The cover value is assumed to be optimal only

when suitability values for all three variables are optimal. The cover value

is assumed to be lowered in direct proportion to low values for any of the

variables. This relationship can be expressed mathematically, as shown in

Equation 6, for DFW, OF, EF, DTS, and ETS.

CSI = SIV11 x SIV12 x SIV13

19

(6)
Figure 5. The relationships between habitat variables used to assess

the cover value of trees and suitability indices for the eastern wild

turkey.

20
Composition component. Optimal habitats for the eastern wild turkey must

provide the proper mix of life requisites. A relatively small area is required

to meet the summer food/brood needs of the turkey. Severa 1 authors have

estimated the amount of area needed in openings to support turkey broods.

Latham (1958) recommended 10% openings, Speake et al. (1975) suggest a need

for 12 to 25% openings, and Porter's (1980) data correspond to a need for

about 14.5% openings. Based on the average of these percentages, it is assumed

that optimal turkey habitats should contain at least 15% of the area in summer

food/brood habitat. It is assumed that, in optimal habitats, the balance of

the area, or 85%, should provide fall, winter, and spring food. Turkeys are

primari ly forest bi rds, but several recent studi es have shown that they may

attain dense populations in areas with an even mix of forest cover and open

lands. Turkeys in Minnesota survived in areas with only 12% forest cover

(Hecklau et al. 1982). This model assumes that in ideal habitats, 50% or more

of the area should provide optimal levels of cover. Habitats with less than

10% of the area providing cover are assumed to be unsuitable. The relationships between the variables used to assess habitat composition and suitability

indices (SIV14, SIV15, and SIV16) for the eastern wild turkey are presented in

Figure 6.

This habitat model is structured in a flexible manner, such that various

combinations of cover type conditions may exist to provide the optimal mix of

life requisites. For example, assuming that the appropriate habitat variables

(VI through V13) are optimum, the model would rate either of the following

cover type mixes as optimum:

1. 85% forest cover, 15% pasture

2. 50% forest cover, 35% cropland, 15% pasture

HSI determination. The overall value of a habitat for eastern wild

turkeys is a funct i on of the qua1i ty, quant i ty , and i nterspersi on of 1ife

requisites. Interspersion is considered by the habitat variable (V3) that

measures the di stance from open areas to forest cover. Several steps must be

followed to determine the quality and quantity of life requisites for the

turkey, as follows:

1. Determine suitability index (SI) values for each variable in the

appropriate cover type by entering the field data into the appropriate SI graphs.

2. Calculate life requisite values in each cover type by using the SI

values in the appropriate equations.

3. Determine the relative area (%) of each cover type used by turkeys

within the study area, as follows:

Relative area (%) for cover type A = ~~~:lo:r~~v~~ ;

lYe A x 100

cover types used by

the turkey

21
Fig. 6a Fig. 6b

a 25 50 75 100

t' 0.4

LO

......

:>

0.8

x

0.6 t:

......

:.a 0.2 to

oj..>

.....

a 5 10 15 20+

0.2

1. a-+---...................,L._........~_+-_-+-

t' 0.4

'd"

......

:>

0.8

x

0.6 t:

......

.....

.....

..0

to

oj..>

.....

Percent of area providing

equivalent optimum summer

food/brood habitat

Percent of area providing

equivalent optimum fall,

winter, spring food

Figure 6. The relationships between the variables used to assess

habitat composition and suitability indices for the eastern wild

turkey.

22
4. Multiply the life requisite values for each cover type by the

relative area (%) of that cover type, and sum these products for

each life requisite.

5. To determine the overall life requisite values, enter the value from

step 4 for each life requisite into the appropriate SI graph

(Fig. 6a-c). The resulting index values are the overall life

requisite values.

6. The HSl for the entire study area is equal to the lowest of the

overall life requisite values.

Application of the Model

Summary of model variables. Fourteen habitat variables and three composition variables are used in this model to determine life requisite values for

the eastern wild turkey. The relationship between habitat variables, life

requisites, cover types, and the HSl for the turkey are illustrated in

Figure 7. The spec ifi c trees that provi de food for the eastern wi 1d turkey

vary across the geographic range of the turkey. It is suggested that users

develop a specific list of both hard and soft mast producing trees for use in

Figure 2a and 2b.

Definitions of variables and suggested measurements techniques (Hays

et al. 1981) are provided in Figure 8.

Model assumptions. Despite the abundance of information and research

that has been gathered concerning the eastern wild turkey, their specific

habitat requirements are not well understood (Bailey and Rinnel 1968; Kennamer

et al. 1980; Little 1980; Hurst 1981). Numerous assumptions were made in the

transformation of the published habitat information on eastern wild turkeys to

the suitability index relationships and formulas used in this model. The

major assumptions in the model are listed below.

1. The habitat variables and life requisite relationships apply to the

entire geographic range of the eastern wild turkey.

2. Water is not a limiting factor.

3. Nest sites will be present if fall, winter, and spring food, cover,

and summer food! brood needs are met.

4. Optimal fall, winter, and spring food values may be provided by

crops alone, by the combined value of crops and mast from trees and

shrubs, or by the combined value of mast from trees and shrubs.

5. The relationships for hard mast were developed using data from oaks.

It is assumed that these relationships apply to all hard mast

producing trees.

23
Habitat variable Li fe regu isite Cover tYpes

Percent herbaceous canopy cover I

Ioo::--------Summer food/brood DFW,DF,ETS,DTS--

Average height of herbaceous------'~ habitat

canopy (summer)

Distance to forest or tree Summer food/brood DS,ESS,DSS, I

savanna cover types habitat G,F,P/H

Average dbh of hard mast produc- ing trees that are 225.4 cm dbh

Number of hard mast producing trees/ha that are 25.4 cm dbh ~----------~/ Fal I, winter, _____ /' food

Percent canopy closure of soft

mast producing trees

Percent sh rub crown cove r i

sp ri ng DFW, EF, DF, ETS,DTS--

I HSI

N

Percent of shrub crown cover r Fal I, winter, spring ES,DS,ESS,DSS I

comprised of soft mast food

producing shrubs

Type of crop I

Overwinter crop management ------- Fall, winter, spring C I

food

Distance to a tree dominated ----- cover type

Percent tree canopy cover I Cover DFW,EF,DF,ETS,DTS

Average dbh of overstory trees

Percent of forest canopy

comp r i sed of eve rg reens ------

Figure 7. Relationships between habitat variables, life requisites,

cover types, and the HSI for the eastern wild turkey.
Variable (definition)

Percent herbaceous canopy

cover (the percent of the

ground surface that is

shaded by a vertical projection of all non-woody

vegetation).

Average height of herbaceous canopy (summer)

(the average vertical

distance from the ground

surface to the dominant

height stratum of the

herbaceous vegetative

canopy) .

Distance to forest or

tree savanna cover

types (the distance

from random points to

the nearest edge of a

forest or tree savanna

cover type).

Average dbh of hard mast

producing trees that are

25.4 cm (10 inches)

dbh [the average diameter

of all hard mast producing

trees that exceed 25.4 cm

(10 inches) diameter at

1.4 m (4.5 ft) above

ground].

Number of hard mast producing trees/ha that are

25.4 cm (10 inches)

dbh [actual or estimated

number of hard mast producing trees per ha that are

25.4 cm (10 inches)

diameter at 1.4 m (4.5 ft)

above ground].

Cover types

DFW,DF,ETS,DTS,

DS,ESS,DSS,G,F,

P/H

DFW,DF,ETS,DTS,

DS,ESS,DSS,G,F,

P/H

DS,ESS,DSS,

G,F,P/H,C

DFW,EF,DF,ETS,

DTS

DFW,EF,DF,ETS,

DTS

Suggested technique

Line intercept,

quadrat

Line intercept,

graduated rod

Remote sensing

Quadrat; Biltmore

stick or diameter

tape

Quadrat

Figure 8. Definitions of variables and suggested measurement techniques.

25
Variable (definition)

Percent canopy closure of

soft mast producing trees

[the percent of the

ground surface that is

shaded by the vertical

projection of the canopies

of trees that produce seeds

encased in a pulpy mass

(e.g., cherry, hawthorn,

etc.)].

Percent shrub crown

cover [the percent of

the ground surface

that is shaded by a

vertical projection

of the canopies of

woody vegetation

5.0 m (16.4 ft) tall].

Percent of shrub crown

cover comprised of soft

mast producing shrubs

(the relative percent

of the amount of soft

mast producing shrubs

compared to all shrubs,

based on crown cover).

Type of crop (the

present or last crop

grown. Categories are:

corn or soybeans; other

grains; and other crops).

Overwinter crop management (an evaluation of

the winter availability

of agricultural crops

based on management.

Categories are: > 5% of

crop left unharvested;

1 to 5% of crop left

unharvested; crop

harvested, spring plowed;

crop harvested, fall

plowed) .

Cover types

DFW, EF,OF, ETS,

DTS

DFW,EF,DF,ETS,

DTS,ES,DS,ESS,

DSS

DFW,EF,DF,ETS,

DTS,ES,DS,ESS,

DSS

C

C

Figure 8. (continued).

26

Suggested technique

Line intercept

Line intercept,

quadrat

Line intercept,

quadrat

Observation, local

data

Observation, local

data
Variable (definition)

Percent tree canopy

closure [the percent

of the ground surface

that is shaded by a

vertical projection of

the canopies of woody

vegetation 5.0 m

(16.4 ft) in height].

Average dbh of overstory trees [the

average diameter at

1.4 m (4.5 ft) above

the ground of those

trees that are 80%

of the height of the

tallest tree in the

stand].

Percent of forest canopy

comprised of evergreens

(the relative percent of

the amount of evergreen

tree canopy compared to

the total tree canopy).

Cover types

DFW,EF,DF,ETS,

DTS

DFW,EF,DF,ETS,

DTS

DFW,EF,DF,ETS,

DTS

Figure 8. (concluded).

Suggested technique

Remote sensing, line

intercept

Cruise for tallest

trees in stand.

Sample with optical

range finder and

Biltmore stick on

strip quadrat.

Li ne intercept,

remote sensing

6. The abundance of insects for broods is directly related to the

biomass and structure of herbaceous vegetation.

7. Interspersion of life requisites (fall, spring, winter food; cover;

and summer food/brood habitat) is only a concern when a cover type

does not provide one or more of these life requisites.

8. For individual life requisites, optimal overall conditions are

provided by a specific mix of both quantity and quality of an area

providing the requisite. It is assumed that optimum overall conditions for a life requisite may still exist, even if individual cover

types contain less than optimum quality, if this lack of quality can

be compensated for by an increased quantity of the resource being

present.

27
SOURCES OF OTHER MODELS

Williamson and Koeln (1980) developed a linear additive model to define

areas of different habitat suitability for wild turkeys in forested areas of

Virginia. Seven habitat factors are used in the model, with each factor given

a value depending on its condition, and also given a relative weighting factor

in comparison to other factors. The value of a particular forest stand is

equal to the sum of all habitat factors. The seven habitat factors are: mast

species diversity; proximity to permanent water; proximity to forest openings;

mast availability; competition; forest contiguity; and proximity to roost

si tes.

Armbruster and Lewis (1980) developed an additive habitat model for

eastern wild turkeys in central Missouri. The model assesses various habitat

characteristics in bottomland hardwoods, upland hardwoods, old fields, pastures

and hayl ands, and croplands, and determi nes a numerica 1 value for each of

these cover types. The model does not provide a method to determine a single

value for a composite of several different cover types. Habitat characteristics in this model include: tree species; number of food plant species;

habitat edge; grazing pressure; tree size class and canopy closure; nesting

cover; crop practices; and distances between cover types.

REFERENCES

Anderson, R. J., and D. E. Samuel.

mines as wild turkey brood range.

1980. Evaluation of reclaimed surface

Proc. Wild Turkey Symp. 4:186-202.

Armbruster, M. J., and J. B. Lewis. 1980. Eastern wild turkey. Pages 27-41

in T. S. Baskett, D. A. Darrow, D. L. Hallett, M. J. Armbruster, J. A.

Ellis, B. F. Sparrowe, and P. A. Korte. A handbook for terrestrial

habitat evaluation in central Missouri. U.S. Fish Wildl. Servo Res.

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Bailey, R. W. 1980. The wild turkey status and outlook in 1979. Proc. Wild

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Bailey, R. W., and K. T. Rinnell. 1968. History and management of the wild

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Bailey, R. W., J. R. Davis, J. E. Frampton, J. V. Gwynn, and J. Shugars.

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Habi tat Requi rements and Habi tat Management for the Wild Turkey in the

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Barwick, L. H., and D. W. Speake. 1973. Seasonal movements and activities of

wild turkey gobblers in Alabama. Pages 125-133 in G. C. Sanderson and

H. C. Schultz, eds. Wild turkey management, current problems and

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28
Blackburn, W. E., J. P. Kirk, and J. E. Kennamer. 1975. Availability and

utilization of summer foods by eastern wild turkey broods in Lee County,

Alabama. Proc. Wild Turkey Symp. 3:86-107.

Bortner, J. B., and J. W. Bennett. 1980. Observations of wild turkey winter

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37:243-248.

Christisen, D. M., and L. J. Korschgen. 1955. Acorn yields and wildlife

usage in Missouri. Trans. N. Am. Wildl. Conf. 20:337-357.

Dalke, P. D., W. K. Clark, Jr., and L. J. Korschgen. 1942. Food habit trends

of the wild turkey in Missouri as determined by dropping analysis. J.

Wildl. Manage. 6(3):237-243.

Davis, J. R. 1976. Management for Alabama wild turkeys. Alabama Dept.

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Dickson, J. G., C. D. Adams, and S. H. Hanley. ~978. Response of turkey

populations to habitat variables in Louisiana. Wildl. Soc. Bull.

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Eaton, S. W., F. M. Evans, J. W. Glidden, and B. D. Penrod. 1976. Annual

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23(1):20-33.

Eichholz, N. F., and R. L. Marchinton. 1976. Dispersal and adjustment to

habitat of restocked wild turkeys in Georgia. Proc. Southeastern Assoc.

Game Fish Commissioners 29:373-378.

Ellis, J. E., and J. B. Lewis. 1967. Mobility and annual range of wild

turkeys in Missouri. J. Wildl. Manage. 31(3):568-581.

Everett, D. D., Jr. 1982. Factors limiting populations of wild turkeys on

state wildlife management areas in north Alabama. Ph.D. Diss., Auburn

Univ., Alabama. 135 pp.

Frederick, R. B., E. E. Klaas, G. A. Baldassarre, and K. E. Reinecke. 1984.

A method for sampling waste corn. J. Wildl. Manage. 48(1):298-303.

Gingrich, S. F. 1971. Stocking, growth, and yield of oak stands. Proc. Oak

Symp. 1:65-73.

Glover, F. A. 1948. Winter activities of wild turkey in West Virginia. J.

Wildl. Manage. 12(4):416-427.

Glover, F. A., and R. W. Bailey. 1949. Wild turkey foods in West Virginia.

J. Wildl. Manage. 13(3):255-265.

Goodrum, P. D., V. H. Reid, and C. E. Boyd. 1971. Acorn yields, characteristics, and management criteria of oaks for wildlife. J. Wildl. Manage.

35(3):520-532.

29
Hamrick, W. J., and J. R. Davis. 1972. Summer food items of juvenile wild

turkeys. Proc. Southeastern Assoc. Game Fish Commissioners 25:85-89.

Hays, R. L., C. S. Summers, and W. Seitz. 1981. Estimating wildlife habitat

variables. U.S. Fish Wildl. Servo FWS/DBS-81/47. 111 pp.

Healy, W. M. 1977. Wild turkey winter habitat in West Virginia cherry-maple

forests. Trans. Northeastern Sect. Wildl. Soc. 34:7-12.

1978. Feeding activity of wild turkey poults in relation to

ground vegetation and insect availability. Ph.D. Diss., West Virginia

Univ., Morgantown. 117 pp.

1981. Habitat requirements of wild turkeys in the southeastern

mountains. Pages 24-34 in P. T. Bromley and R. L. Carlton, eds. Proc.

of the Symp.: Habi tat Requi rements and Habi tat Management for the Wil d

Turkey in the Southeast, Richmond, Virginia.

Healy, W. M., and L S. Nenno.

management of cl eari ngs

11(2): 113-120.

1983. Minimum maintenance versus intensive

for wild turkeys. Wildl. Soc. Bull.

Heckl au , J. D., W. F. Porter, and W. M. Shields. 1982. Feasibility of

transplanting wild turkeys into areas of restricted forest cover and high

human density. Trans. Northeastern Sect. Wildl. Soc. 39:96-104.

Hillestad, H. D. 1973. Movements, behavior, and nesting ecology of the wild

turkey in eastern Alabama. Pages 109-125 in G. C. Sanderson and H. C.

Schultz, eds. Wild turkey management. Missouri Chapt. Wildl. Soc. and

Univ. Missouri Press, Columbia.

Hillestad, H. 0., and D. W. Speake. 1970. Activities of wild turkey hens and

poults as influenced by habitat. Proc. Southeastern Assoc. Game Fish

Commissioners 24:244-251.

Hurst, G. A. 1978. Effects of controlled burning on wild turkey poult food

habits. Proc. Southeastern Assoc. Fish Wildl. Agencies 32:30-37.

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coastal plain. Pages 2-13 in P. T. Bromley and R. L. Carlton, eds.

Proc. of the Symp.: Habitat~equirements and Habitat Management for the

Wild Turkey in the Southeast, Richmond, Virginia.

Hurst, G. A., and B. D. Stringer, Jr. 1975. Food habits of wild turkey

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Kennamer, J. L, J. R. Gwaltney, and K. R. Sims. 1980. Food habits of the

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Proc. Wild Turkey Symp. 4:246-250.

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Washington, DC.

30
1973. April foods of wil d turkeys in Mi ssouri . Pages

143-151 in G. C. Sanderson and H. C. Schultz, eds. Wild turkey management. Missouri Chapt. Wildl. Soc. and Univ. Missouri Press, Columbia.

Koz t cky , E. L: 1942. Pennsylvania wild turkey food habits based on dropping

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Latham, R. M. 1958. Factors affecting distribution and abundance of wild

turKeys in Pennsylvania. Ph.D. Thesis, Pennsylvania State Univ.,

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Lewis, J. B., and E. Kurzejeski. 1984.

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W-13-R-38. 43 pp.

Wild turkey productivity and poult

Missouri Dept. Cons. Fed. Aid Proj.

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Southeastern Assoc. Game Fish Commissioners 18:48-56.

Lindzey, J. S. 1967. Highlights of management. Pages 245-260 in O. H.

Hewitt, ed. The wild turkey and its management. The Wild~ Soc.,

Washington, DC.

Little, 1. W. 1980. Wild turkey restoration in "marq i nal " Iowa habitats.

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Markley, M. H. 1967. Limiting factors. Pages 199-244 in O. H. Hewitt, ed.

The wild turkey and its management. The Wildl. Soc., Washington, DC.

Martin, A. C., F. H. May, and T. E. Clarke. 1939. Early winter food preferences of the wil d turkey on the George Washi ngton Nati ona1 Forest.

Trans. N. Am. Wildl. Conf. 4:570-578.

Martin, D. D., and B. S. McGinnes. 1975. Insect availability and use by

turkeys in forest clearings. Proc. Wild Turkey Symp. 3:70-75.

McQuilkin, R. A., and R. A. Musbach. 1977.

tree reservoirs in southeastern

41(2):218-225.

Pin oak acorn production on green

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Mosby, H. S., and C. O. Handley. 1943. The wild turkey in Virginia, its

status, life history, and management. Div. Game Comm. Inland Fish.,

Richmond, VA. 281 pp.

Nenno, E. S., and J. S. Lindzey. 1979. Wild turkey poult feeding activity in

old field, agricultural clearing, and forest communities. Trans. Northeastern Sect. Wildl. Soc. 36:97-109.

Owen, C. N. 1976. Food habits of wild

fields in east central Mississippi,

edges on arthropod populations in

M.S. Thesis. Mississippi State

Cited by Hurst 1978.

31

turkey poults in pine stands and in

and the effects of mowing hayfield

relation to poult food production.

Univ., Mississippi State. 62 pp.
Pack. J. C., R. P. Burkert. W. K. Igo. and D. J. Pybus. 1980. Habitat

utilized by wild turkey broods within oak-hickory forests of West

Virginia. Proc. Wild Turkey Symp. 4:213-224.

Porter. W. F. 1977 . Home range of wil d turkeys in southeastern Mi nnesota.

J. Wildl. Manage. 41(3):434-437.

1978. The ecology and behavior of the wild turkey (Meleagris

gallopovo) in southeastern Minnesota. Ph.D. Thesis. Univ. Minnesota.

Minneapolis. 122 pp.

1980. An evaluation of wild turkey brood habitat in southeastern Minnesota. Proc. Wild Turkey Symp. 4:203-213.

Porter. W. F.• R. D. Tangen. G. C. Nelson. and D. A. Hamilton. 1980. Effects

of corn food plots on wild turkey in the Upper Mississippi Valley. J.

Wildl. Manage. 44(2):456-462.

Pybus. D. J. 1977. Understory characteristics and utilization by wild turkey

broods in West Virginia. M.S. Thesis. West Virginia Univ .• Morgantown.

106 pp.

Raybourne , J. W. 1968. Telemetry of turkey movements. Proc. Southeastern

Assoc. Game Fish Commissioners 22:47-54.

Shaw. S. P. 1971. Wildlife and oak management. Proc. Oak Symp. 1:84-89.

Speake. D. W. 1980. Predation on wild turkeys in Alabama. Proc. Wild Turkey

Symp. 4: 86-101.

Speake. D. W.• L. H. Barwick. H. O. Hillestad. and W. Stickney. 1969. Some

characteristi cs of an expandi ng turkey population. Proc. Southeastern

Assoc. Game Fish Commissioners 23:46-53.

Speake. D. W.• T. E. Lynch. W. J. Fleming. G. A. Wright. and W. J. Hamrick.

1975. Habitat use and seasonal movements of wild turkeys in the southeast. Proc. Wild Turkey Symp. 3:122-130.

Tzt l kowsk i , W. M. 1971. Winter roost sites of wild turkeys in southwest

Pennsylvania. Trans. Northeastern Sect. Wildl. Soc. 28:167-178.

U.S. Fish and Wildlife Service. 1981. Standards for the development of

habitat suitability index models. 103 ESM. U.S. Fish Wildl. Serv .• Div.

Ecol. Servo n.p.

Williams. L. E.. Jr. 1981. The book of the wild turkey. Winchester Press,

Tulsa. 181 pp.

Williamson. J. F.• and G. T. Koeln. 1980. A computerized wild turkey habitat

evaluation system. Proc. Wild Turkey Symp. 4:233-239.

32
Wright, G. A., and D. W. Speake. 1975. Compatibility of the eastern wild

turkey with recreational activities at Land Between the Lakes, Kentucky.

Proc. Southeastern Assoc. Game Fish Commissioners 29:578-584.

Wunz, G. A. 1971. Tolerances of wild turkeys to human disturbance and limited

range. Trans. Northeast Sect. Wildl. Soc. 28:159-165.

33
OI"T\ONAL FOR'" 272 (

IFormerly NTI:>-3S1

Department of Commerce

(S.. ANSI-Z39.18)

502n·101

REPORT DOCUMENTATION 11. ~EPORT ~. Report 82(10.106~~ '11. .Reclp.ent'. Acclss,o" No.

PAGE I Blologlcal

4. Titll Ind Subtitle RlPOrt Oltl

August 1985 Habitat Suitability Index ~odels: Eastern Hild Turkey 6. -~

7. Authorl.) 8. Plrtormin. Or.lnizltion RIPl. No.

Richard L. Schroeder 9. Pertormin. O,,"niution N..... Ind Addr... Western Energy and Land Use Team 10. Pro,lct/TIsk/Work Unit No.

U.S. Fish and Wildlife Service

2627 Redwing Road 11. ContrlctlC) or GrlntlG) No.

Fort Co 11 ins, CO 80526-2899 IC)

IGl

1~ SpoRSorin. Or.lniution Nlml Ind Add..... Wes tern Energy and Land Use Team 13. Type of Report & Period COYlrld

Division of Biological Services

Research and Development

Fish and Wildlife Service 14.

Deoartmen.Uf the Interior Wrlc::hinnt hn DC :mno 15. Suppllmlntlry Notl' The Biological Report series was initi~ted in October 1984 to replace the FWSjOBS series published since 1976. The report number assigned to this model

foll ows consecutively from the Habitat SUita~llitY)Index models published as FVJSjOBS- 8?/1O nnw rlC:: R'i n l n o i r-a I n R? 10 16. Abstrlct (Limit: 200 worm)

A review and synthesis of existing information were used to develop a Habita t

Suitabil t ty Index (HSI) model for the eastern wild turkey U~el eagris gallopavo sylvestris). The model consol idates habitat use information into a framework

appropriate for field application, and is scaled to produce an index between 0.0

(unsuitable habitat) and 1.0 (optimum habitat). HSI models are designed to be used

with Habitat Evaluation Procedures previously developed by the U.S. Fish and Wildlife

Service.

17. Document Anllysi. I. Descriptors

Birds

Wildlife

Habitabil ity

Mathematical models

I b. Identlfiers/Open·Ended Tlrm.

Eastern wild turkey I

Meleagris gallopavo sylvestris

I c. COSATI Filld/GnluP

18. AYlillbillty Stltlml"; lIt. Security CII.s (Tlli. RlPOrt) I 21. No of PI,.. !

Release unlimit~d Unclassified , 33 _-.J I20. Security CII,' (Til,. PI.e) i 22~ Price I I Uncl as si ft ed ! I

4-77

*u.S. GOVERNMENT PRINTING OFFICE: 1985-580246/25345
.. ....,-. .. ..

""

*Headquarters, 0lvI5 10n Of Biolog ical

services. Wasn,ngton. DC

)( Eastern Energy and Land Use Team

Leerown. WV

* Naloonal Coastal Ecosystems Team

Slide ll LA

• Western Energy aM LaM Use Team

FI ccu.ns. CO

• Locat ions of RegIonal Ollices

UGION 1

Rqiunlll Director

O.S. Fish lind Wildlife Service

Uoyd Five Hundred Building, Suite 1692

500N.E. Multnomah Street

Portland, Oregon 97232

REGION 4

Regional Director

U.S. Fish and Wildlife Service

Richard B. Russell Building

75 Spring Street, S.W.

Atlanta, Georgia 30303

,

,

I __r----

6!

,----- L, J_

1

, : ,--- I ,

I

REGION 2

Regional Director

U.S. Fish and Wildlife Service

P.O. Box 1306

Albuquerque, New Mexico 87103

REGION S

Regional Director

U.S. Fish and Wildlife Service

One Gateway Center

Newton Comer, Massachusetts 02158

REGION 7

Regional Director

U.S. Fish and Wildlife Service

10II E. Tudor Road

Anchorage, Alaska 99503

,."

REGION 3

Regional Director

U.S. Fish and Wildlife Service

Federal Building, Fort Snelling

Twin Cities, Minnesota 5SIII

REGION 6

Regional Director

U.S. Fish and Wildlife Service

P.O. Box 25486

Denver Federal Center

Denver, Colorado 80225
DEPARTMENT OF THE INTERIOR

u.s. FISH AND WILDLIFE SERVICE

As the Nation's principal conservation asency, the Department of the Interior has responsibility for most of our .nationally owned public lands and natural resources. This includes

fosterins the wisest use of our land and water resources, protecting our fish and wildlife,

preserving th.environmental and cultural'values of our national parks and historical places,

and providing for the enjoyment of life throulh outdoor recreation. The Department assesses our energy and mineral resources and works to assure that their development is in

the best interests of all our people. The Department also has a major responsibility for

American Indian reservation communities and for people who live in island territories under

U.S. administration.