FWS/OBS-8211 0.62

DECEMBER 1983

., Center . , JPrvice

ard

HABITAT SUITABILITY I DEX MODELS:

FIELD SPARROW

'1 and Wildlife Service

SK

~~4 .. Department of the Interior

no. 82-

10. 62
FWS/OBS-82/10.62

December 1983

HABITAT SUITABILITY INDEX MODELS: FIELD SPARROW

by

Patrick J. Sousa

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:

Sousa, P. J. 1983. Habitat suitability index models: Field sparrow. U.S.

Fish Wildl. Servo FWS/OBS-82/10.62. 14 pp.
PREFACE

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

(FWS/OBS-82/10), which provides habitat information useful for impact assessment and habitat management. Several types of habitat information are

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

data that can be used to derive quantitative relationships between keyenvironmental variables and habitat suitability. The habitat use information provides

the foundation for HSI models that follow. In addition, this same information

may be useful in the development of other models more appropriate to specific

assessment or evaluation needs.

The HSI Model Section documents a habitat model and 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 application information includes descriptions of the geographic ranges and seasonal

application of the model, its current verification status, and a listing of

model variables with recommended measurement techniques for each variable.

In essence, the model presented herein is a hypothesis of species-habitat

relationships and not a statement of proven cause and effect relationships.

Resul ts of model performance tests, when avail abl e, are referenced. However,

models that have demonstrated reliability in specific situations may prove

unreliable in others. For this reason, feedback is encouraged from users of

this model concerning improvements and other suggestions that may increase the

utility and effectiveness of this habitat-based approach to fish and wildlife

planning. 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

PREFACE................................................................ iii

ACKNOWLEDGMENTS .....................................•.................. vi

HABITAT USE INFORMATION 1

Genera 1 1

Food 1

Water 1

Cover 2

Reproduction 2

I nterspersion 3

Special Considerations............................................ 3

HABITAT SUITABILITY INDEX (HSI) MODEL. 4

Model Applicability............................................... 4

Model Description................................................. 5

Model Relationships............................................... 8

Application of the Model.......................................... 10

SOURCES OF OTHER MODELS 11

REFERENCES 12

v
ACKNOWLEDGMENTS

Dr. Louis Best reviewed two earlier drafts of the HSI model for the field

sparrow. Hi s comments and suggestions added greatly to the qual i ty of thi s

model and his contributions are gratefully acknowledged. Dr. Best also participated in field validation efforts of the field sparrow HSI model conducted

under the direction of Ms. L. Jean O'Neil, U.S. Army Corps of Engineers,

Waterways Experiment Station. Results of the field validation efforts resulted

in several improvements in the model. Ms. O'Neil's efforts in the field

validation contributed significantly to the final structure of this model.

Word processing of this document was provided by Carolyn Gulzow and Dora

Ibarra. The cover was illustrated by Jennifer Shoemaker.

vi
FIELD SPARROW (Spizella pusilla)

HABITAT USE INFORMATION

General

The preferred habitat of the field sparrow (Spizella pusilla) is old

fields with scattered woody vegetation (Best 1977b). Field sparrows are

distributed primarily in the eastern United States, although they may breed as

far west as Montana to eastern Texas (Walkinshaw 1968). They are resident

species in much of their range.

Food

Field sparrows feed on a variety of plant and animal foods (Martin et al.

1961; Evans 1964; Best 1977a), and their food habits have been described as

flexible (Allaire and Fisher 1975). Food is not considered to be limiting

during the breeding season (Evans 1964; Best 1977a).

Field sparrows typically forage on or near the ground (Allaire and Fisher

1975; Hebrard 1978), although flycatching has also been observed (Hebrard

1978). Foraging perches, such as shrubs, brush piles, or barbed-wire fences,

are often used to reach seeds (All aire and Fisher 1975). Seeds account for

80% to 90% of the fall and winter diet, although vegetative material accounts

for only 45% and 49% of the spring and summer diet, respectively (Martin

et al. 1961). The spring diet of adult field sparrows is varied and includes

insects and other arthropods, grass and forb seeds, and other vegetative

material (Evans 1964).

The diet of nestlings is almost entirely insects [particularly larval

forms of the order Lepidoptera, nymphal forms of the order Orthoptera, and

adult forms of the order Homoptera (Best 1977a)J and spiders (Evans 1964; Best

1977a), although vegetative material and other animal forms have also been

identified (Evans 1964). Adult field sparrows in Illinois were opportunistic

foragers for their young and shifted their foraging habitats from wooded areas

adjacent to the breeding habitat early in the spring to more open sites with

low vegetation later in the breeding season (Best 1977a). The use of wooded

areas for foraging was also reported in a Michigan study area (Evans 1964).

Water

No information on drinking water requirements was found in the literature.

1
Cover

Old fields with scattered woody vegetation (Best 1977b) and brushy fencerows (Walkinshaw 1968) provide the most suitable habitat for the field sparrow.

Territories extend into grassland and forested cover types at times, but these

habitats are less preferred (Best 1979). The field sparrow roosts in the

dense foliage of small trees or bushes (Walkinshaw 1968). Field sparrows

winter in a variety of forested or shrubby habitats (Emlem 1972).

Characteristics of habitats occupied during the breeding season are

discussed in the following section.

Reproduction

Breeding habitat preferred by the field sparrow has been variously

described as a shrub-grassland community (Best 1979); brushy stands with

little or no overstory (Crawford et al. 1981); shrubby fields, forest borders,

and roadsides (Johnston 1947); early successional stages (Shugart and James

1973); brushy fields or grasslands with a few larger trees (Kahl et al. 1981);

and hillsides with shrubby growth, grassy meadows, pastures, and weedy fencerows (Walkinshaw 1936). The common habitat denominator in these studies is

apparently the need for a mixture of shrubby and herbaceous vegetation. The

field sparrow has also been considered a typical forest edge bird (Johnston

1947), and the presence of nearby wooded areas as an early spri ng foragi ng

habitat may be an important factor in habitat suitability (Evans 1964).

The availability of suitable perches (e.g., shrubs, trees, and fences)

has been suggested as a habitat factor that can limit field sparrow populations

(Johnston 1947; Anderson 1979; Lanyon 1981). Factors related to habitat

patchiness may also be limiting (Stauffer and Best 1980). Primary habitat

factors in Missouri were identified as canopy height and stem density of woody

vegetation less than 2.5 cm (1 inch) dbh (Kahl et al . 1981). Habitats with

canopy height ranging from 2 to 8 m (6.6 to 26.2 ft) were occupied, although

the preferred range was 2 to 4 m (6.6 to 13.1 ft). Optimum density of small

di ameter stems was reported as 350 to 700 stems/ha (142 to 283 stems/acre),

although the range in occupied habitats was 25 to 1,050 stems/ha (10 to 425

stems/acre). Secondary habitat characteristics were stem density greater than

2.5 em (1 inch) dbh and the percent vegetative ground cover. Optimum ranges

for these variables were 25 to 50 stems/ha (10 to 20 stems/acre) and 95 to

100% ground cover. Ranges of the secondary variables in occupied habitat were

25 to 500 stems/ha (10 to 202 stems/acre) and 85 to 100%, respectively. Field

sparrow populations in regenerating hardwood stands in Virginia decreased as

canopy height of the stand exceeded 4.5 m (14.8 ft) (CraWford et al. 1981).

Field sparrows were common on grasslands with shrubs following a transmission

line corridor cut in Tennessee, but were expected to decrease as shrub density

increased (Anderson 1979).

Field sparrows nest on the ground (Evans 1964; Fretwell 1969), in low

herbaceous vegetation, or in low shrubs (Walkinshaw 1936; Best 1978). Only 1

of 145 field sparrow nests in a Pennsylvania study area was placed greater

than 0.9 m (3 ft) above the ground (Preston and Norris 1947). Ten nests in a

Scotch pine (Pinus sylvestris) Christmas tree plantation in Minnesota averaged

2
0.44 ± 0.07 m (1.4 ± 0.23 ft) above ground in trees that averaged 1.42 ±

0.08 m (4.66 ± 0.26 ft) tall (Buech 1982). Six of nine nests in an Iowa study

area were located in shrubs, two were in evergreen trees, and one was in forb

cover (Stauffer and Best 1980). Approximately 42% of 129 field sparrow nests

in Illinois were located in standing grass litter, 19% were in forbs, and 39%

were in trees and shrubs (Best 1978). However, a significant shift in nest

placement from herbaceous to woody vegetation occurred through the breedi ng

season. The average nest height increased from a low of 26 cm (10.2 inches)

in May to 48 cm (18.9 inches) in August. A similar shift in nest placement

through the nesting season has also been documented in Michigan (Walkinshaw

1936), Iowa (Crooks and Hendrickson 1953), and Indiana (Nolan 1963). Although

this shift in nest placement has been considered to be correlated with leaf-out

of woody vegetation (Nolan 1963), Best (1978) suggested that the shift results

from unknown factors and not in response to leaf-out. Evans (1978) found a

shi ft from ground nesting to tree and shrub nesting as plant successi on

progressed on an old field in Michigan. Fifty-six percent of all nests were

located in junipers (Juniperus communis) even though junipers made up only a

small portion of the potential nest sites, indicating a preference for this

tree species as a nest site by field sparrows. Nests in junipers were significantly more successful than nests in other sites. Nest height alone was

found to be an insignificant factor in nesting success in Illinois (Best

1978).

Interspersion

Field sparrows are territorial during the breeding season (Walkinshaw

1968; Best 1977b; Evans 1978). Reported territory sizes range from a low of

0.30 ha (0.75 acre) in Iowa (Crooks and Hendrickson 1953) to a high of 2.4 ha

(6 acres) in Michigan (Walkinshaw 1968). Mean territory sizes are typically

less than 0.8 ha (2 acres) (Nolan 1963; Best 1977b; Evans 1978). Average

territory sizes in a Michigan study area decreased from 0.63 ha (1.56 acres)

in 1956 to 0.36 ha (0.89 acre) in 1975, apparently in response to an increase

in the number of junipers (Evans 1978). Territories in a grassland type in

Illinois were significantly larger than in nongrassland types (primarily the

preferred shrub-grassland type) (Best 1977b). The difference in territory

size may have resulted from the low food potential of the grassland or from

the opportunity to expand territories outward because the grassland type was

on the periphery of the preferred shrub-grassland cover type. Field sparrows

in western Virginia were infrequently found in areas of regeneration following

clearcutting that were less than 2 ha (4.9 acres) (Crawford et al. 1981).

Special Considerations

Suitable breeding habitat for the field sparrow may be created by activities such as fire, cutting, or scarification follOWing clearcutting (Crawford

et al. 1981). Fire can be used to maintain suitable shrub-grassland and edge

conditions. However, too frequent burning may eliminate desirable woody

vegetation, and infrequent burning may result in the closure of the woody

canopy (Best 1979). The length of time that habitat is suitable for field

sparrows following clearcutting depends on the growth rate of woody regenerat ion (Crawford et a1. 1981). Habi tats on fast growi ng sites may remain suitable for only 3 to 5 years, while those on slow g'rowing sites may remain

3
suitable for 10 to 15 years. Old field successional habitats on fallow farmlands on Long Island were attractive to field sparrows as nesting habitat from

about 2 to 16 years following cultivation (Lanyon 1981). The field sparrow

does not tolerate habitat disturbance well. particularly the removal of woody

vegetation (Stauffer and Best 1980). An increase in the patchiness of shrubby

vegetation will likely result in an increase in field sparrow populations.

HABITAT SUITABILITY INDEX (HSI) MODEL

Model Applicability

Geographic area. Thi s HSI model was developed for use throughout the

breeding range of the field sparrow (Fig. 1). The breeding range of the field

sparrow is II... from northwestern and southeastern Montana. northern North

Dakota. central Minnesota. north-central Wisconsin. north-central Michigan.

southern Ontario. southwestern Quebec. southern Maine and southern New

Brunswick south to northeastern Colorado (possibly). western Kansas. western

Ok l ahoma , central and southern Texas (west to Irion County), the Gulf Coast

(east to northern Florida) and southern Georgia; also in southern Manitoba

(Winnipeg)1I (American Orn t tho l oqi st s ' Union 1983:701).

Figure 1. Geographic applicability of the field sparrow HSI model within

the United States (adapted from a map prepared by D. B. Ink.ley and C. M.

Raley. Wyoming Coop. Fish. Wildl. Res. Unit. Laramie. from American

Ornithologists· Union 1983).

4
Season. This model was developed to obtain an HSI for habitat used by

the field sparrow during the breeding season (spring through summer).

Cover types. The field sparrow is associated with early successional

habitats with shrubby and herbaceous vegetation during the breeding season and

may use any of the fo 11 owi ng cover types (termi no logy fo 11 ows that of U. S.

Fish and Wildlife Service 1981): Evergreen Shrubland (ES); Deciduous Shrubland

(OS); Evergreen Shrub Savanna (ESS); Deciduous Shrub Savanna (DSS); Grassland

(G); and Forbland (F).

Minimum habitat area. Minimum habitat area is defined as the mi rnmum

amount of contiguous habitat that is required before an area will be occupied

by a speci es. The fi e1d sparrow does not usually i nhabi t areas of forest

regeneration smaller than 2 ha (4.9 acres) (Crawford et al. 1981). It is

assumed in this model that a minimum of 2 ha of habitat must exist or the HSI

will equal 0.0.

Verification level. This HSI model provides habitat information for

impact assessment and habitat management. The model is a hypothesis of

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

relationships.

Earl i er drafts of thi s model were revi ewed by Dr. Loui s Best, based on

his knowledge of the habitat requirements of the field sparrow in old fieldtallgrass prairie habitats of Illinois and Iowa. Many of his review comments

have been incorporated into the current model, with the belief that Dr. Best's

perceptions of field sparrow habitat quality are appropriate throughout the

range of the species.

An attempt at field validation of the model was conducted on 20 sites at

Oak Ridge, Tennessee (O'Neil, pers. comm.). Comparisons between outputs of

several versions of the model and site ratings by Dr. Best resulted in several

changes to the original version of the model. Results of the comparison

between Dr. Best's ratings and the HSI model described below were a productmoment correlation coefficient (r) of 0.53 (p < 0.05) and a Spearman's rank

correlation coefficient (rs) of 0.55 (p < 0.05) (OINeil, pers. comm.). The

following major assumptions must be considered in interpreting these results:

(1) that the expert's perceptions of habitat quality for the field sparrow are

valid throughout the breeding range of the species, even though these perceptions were developed over a limited portion of the range; and (2) that the

expert ratings are highly correlated with actual habitat quality, i.e., that

the expert ratings were a suitable surrogate measure of habitat quality.

Model Description

Overview. This model uses the reproductive habitat needs of the field

sparrow to determine overall habitat quality. It is assumed that cover needs

are met by reproductive habitat needs and that neither food nor water will be

more limiting than the field sparrow's cover/reproductive needs. All of the

life requirements of the field sparrow can be provided within each cover type

in which it occurs, although the presence of nearby wooded areas may add to

the suitability of the habitat.

5
In order to evaluate the cover and reproductive suitability of a habitat,

it is necessary to characterize the habitat in terms of the needs of the field

sparrow. The following section identifies important habitat variables,

describes suitability levels of the variables, and describes the relationships

between variables. The relationships between habitat variables, life

requisites, and cover types used in this model and an HSI value for the field

sparrow is shown in Figure 2.

Habitat variable

Life

requisite Cover types

Percent shrub crown

cover --------. Percent of total shrubs

that are less than

1.5 m (4.9 ft) tall

Percent canopy cover Cover/

of grasses --------1reproduction -- Average height of

herbaceous canopy

(average spring conditions)-----~

Evergreen shrubland

Deciduous shrubland

Evergreen shrub

savanna

Deciduous shrub

savanna

Grassland

Forbland

--HSI

Figure 2. The relationships between habitat variables, life

requisites, and cover types in the field sparrow model.

Cover/reproduction component. Reproductive suitability for the field

sparrow is related to the hei ght and density of both shrubs and herbaceous

vegetation. Optimal habitats occur in old field areas with low to moderate

densities of shrubs and dense, moderately tall grasses. Field sparrows use

shrubs as perch sites and increasingly for nesting as the breeding season

progresses. Since preferred habitat includes a mixture of shrubs and grassy

vegetation, canopy cover of shrubs may serve as one variable to predict habitat

quality. Grasslands with no shrubs are assumed in this model to be unsuitable

for field sparrows, and habitats with greater than 75% shrub cover are considered to be too dense to be used by field sparrows. Shrub cover between 15

and 35% is considered to represent optimum conditions in this ~odel. Although

horizontal patchiness of shrubs may be an important variable influencing field

sparrow habitat (Stauffer and Best 1980; Best, pers. comm.), an evaluation of

horizontal patchiness of shrubs is not included in this model. It is assumed

in this model that an estimate of shrub cover will, in most instances, address

the question of shrub patchiness and distribution. It is also assumed that

optimal shrub cover as described above will represent optimal interspersion of

woody and herbaceous vegetation.

Field sparrows use relatively short shrubs for nesting and taller shrubs

for song perches (Best, pers. comm.), and an estimate of average shrub height

may not adequately reflect this condition. Since field sparrows usually nest

6
low in shrubs, it appears reasonable to assume that most shrubs should be

relatively short in order to provide optimal nesting conditions. Habitats

with 50 to 75% of the shrubs < 1.5 m (4.9 ft) tall are assumed to provide the

optimum mixture of high and low shrubs. Habitats where all shrubs are < 1.5 m

(4.9 ft) tall are assumed to provide less than optimal habitat due to a

scarcity of preferred perch sites. Habitats with all shrubs> 1.5 m (4.9 ft)

tall are assumed to provide relatively low quality habitat due to a scarcity

of preferred nest sites. It is assumed in this model that a scarcity of low

nest sites has a more significant impact on the suitability of shrubs to field

sparrows than does a scarcity of perch sites (i .e., areas with all shrubs

> 1.5 m are less suitable than areas with all shrubs < 1.5 m). The suitability levels corresponding to these conditions were based on field validation

efforts of an earlier draft of this model (O'Neil, pers. comm.).

Overall shrub suitability for the field sparrow is a function of both

shrub density and height di str tbut t on . It is assumed in this model that the

shrub variable with the lowest suitability level will determine the overall

shrub suitability level. This assumption is based on results of correlations

of model outputs from several combi nat ion functions to expert ratings of 20

sites for field sparrows (O'Neil, pers. comm.).

Grasses are used much more frequently than forbs for nest sites and as a

food source by field sparrows (Best 1978). Optimal grass density is assumed

to be from 50% to 90% canopy cover in this model. These levels are assumed to

provide adequate nesting substrate, an abundant food source, and no obstruction

to movement through the grasses. Canopy cover < 50% is assumed to provide

less than optimal nesting substrate and food sources. Canopy cover> 90% is

assumed to provide optimal levels of nesting substrate and food resources, but

less than optimal conditions for unrestricted movement through the vegetation.

Optimal height of herbaceous vegetation during the period when nesting is

concentrated in herbaceous vegetation (i .e., May-June) is assumed to be 16 to

32 cm (6.3 to 12.6 inches), and suitability is assumed to decrease as herbaceous hei ght increases above 32 cm, due to increased di ffi culty in reachi ng

ground level where most nests are located. Average herbaceous height greater

than 40 cm (15.8 inches) duri ng the May-June peri od is assumed to represent

average suitability to nesting field sparrows. Herbaceous vegetation that

averages less than 5 cm (2 inches) is assumed to provide inadequate concealment

for field sparrow nests. Overall suitability related to the herbaceous

component of the habitat is a function of both herbaceous height and density

of grasses. It is assumed in this model that the final value of herbaceous

vegetation to field sparrows will be determined by the lowest suitability

level of the two variables related to herbaceous vegetation. This assumption

is based on results of correlations of model outputs from several combination

functions to expert ratings of 20 sites for field sparrows (O'Neil, pers.

comm.) .

The overall cover/reproductive suitabil ity during the breeding season is

a function of both the shrub and herbaceous components of the habitat. It is

assumed that shrubs and herbaceous growth are equa lly important and that

optimal levels of both are necessary to provide optimal habitat conditions.

Low levels of either component are assumed to be partially compensated for by

7
high values of the other component, except when either component provides no

suitability for the field sparrow. If either the shrub or herbaceous component

is absolutely unsuitable for field sparrows, then the entire habitat is assumed

to be unsuitable. These assumptions suggest that a combination of suitability

indices of the shrub and herbaceous components should include a multiplicative

function.

Model Relationships

Suitability Index (SI) graphs for habitat variables. This section contains suitability index graphs that illustrate the habitat relationships

described in the previous section.

Cover

ES,DS,

ESS,DSS,

G,F

Variable

Percent shrub crown

cover.

1.0

>< 0.8

OJ

"'0

s::

...... 0.6

.~

r- 0.4 'r-

..0

ttl

.~ 0.2

U"l

0.0

a 25 50 75

%

100

ES,DS, V2 Percent of total 1.0

ESS,DSS, shrubs that are less,

G,F than 1.5 m (4.9 ft) >< 0.8

OJ

ta11. "'0

s::

...... 0.6

'rr-

'r- 0.4 ..0

ttl

'r- 0.2

U"l

0.0

a 25 50 75 100

%

8 tv
ES,DS, V3 Percent canopy cover of 1.0

ESS,DSS, grasses.

G,F >< O~8 (1)

"0

C

...... 0.6

>,

+.>

;= 0.4 .r-

..0

"'

+.>

.; 0.2

V}

0.0

0 25 50 75 100

%

1.0 ES,DS, V4 Average height of

ESS,DSS, herbaceous canopy

G,F (average spring x 0.8 (1)

conditions). "0

c

......

>, 0.6 +.>

.r-

'r- 0.4

..0

"'

+.>

.r-

::s 0.2

V}

0.0

0 10 20 30 40+(cm)

0 4 8 12 16+(in)

Equations. In order to obtain a cover/reproduction value for the field

sparrow, the SI values for the appropriate variables must be combined with the

use of an equation. A discussion and explanation of the assumed relationships

between variables was included under Model Description, and the specific

equation in this model was chosen to mimic these perceived biological relationships as closely as possible. Also, the equation selected in this study

provided the highest correlation with expert ratings of 20 sites in Tennessee

for field sparrows (OINeil, pers. comm.). The results of several other

combinations of suitability indices were compared to expert ratings, including

equations that gave greater importance to the shrub component of field sparrow

habitat. However, these other combinations resulted in lower correlations than

the equation selected for this model. The suggested equation for obtaining a

cover/reproduction value in all cover types potentially used by the field

9
sparrow is the geometric mean of the mlnlmum suitability levels of the shrub

and herbaceous components. That is, the geometric mean of the lowest of the

suitability indices for Variable 1 and Variable 2 and the lowest of the suitability indices for Variable 3 and Variable 4. This can be expressed

mathematically as the following equation:

HSI determination. Cover/reproduction was the only life requisite considered in this model, and the HSI for the field sparrow is equal to the life

requisite value for cover/reproduction.

Application of the Model

Definitions of variables and suggested field measurement techniques (Hays

et al. 1981) are in Figure 3.

Variable (definition) Cover types Suggested techniques

V1 Percent shrub crown ES,DS,ESS,DSS, Line intercept

cover [the percent of G,F

the ground shaded by a

vertical projection of

the canopies of woody

vegetation less than

5 m (16.5 ft) in

height].

V2 Percent of total ES,DS,ESS,DSS, Line intercept and

shrubs less than G,F graduated rod, or

1.5 m (4.9 ft) tall. ocular estimate

V3 Percent canopy cover ES,DS,ESS,DSS, Ocular estimation of

of grasses (the percent G,F cover

of the ground shaded by

a vertical projection

of grasses).

Figure 3. Definitions of variables and suggested measurement techniques.

10
Variable (definition)

Average height of

herbaceous canopy

(average spring

conditions) (the

average vertical

distance from the

ground surface to

the dominant height

stratum of the herbaceous vegetative

canopy during MayJune, when nesting

of field sparrows

is concentrated in

herbaceous vegetation).

SOURCES OF OTHER MODELS

Cover types

ES,DS,ESS,DSS,

G,F

Figure 3. (concluded).

Suggested techniques

Graduated rod

An HSI model for the field sparrow was developed by Cole and Smith (1983)

for use on abandoned strip mines in West Virginia. Variables included in the

mode 1 are percent cover and mean hei ght of herbaceous vegetation, percent

cover and mean height of shrubs, and percent cover and mean height of trees.

Equations were developed by trial and error to obtain the highest correlation

between model outputs and observed populations on 10 study sites. The selected

equation resulted in a coefficient of determination (r 2 ) of 0.48 (p < 0.05)

and a Spearman's rank correlation coefficient (r ) of 0.71 (p < 0.05). The

s

model by Cole and Smith (1983) was also used to calculate HSI values for 20

sites in Tennessee in conjunction with field validation of the current model

(OINeil, pers. comm.). Comparison of model outputs to site ratings by

Dr. Louis Best resulted in a Spearman's rank correlation coefficient of -0.21.

Possible explanations for the poor rank correlation include: (1) expert

ratings of the Tennessee sites were not valid measures of habitat suitability;

(2) data collection on the Tennessee sites did not precisely correspond to the

data needs of the model of Cole and Smith (1983); or (3) the model developed

by Cole and Smith (1983) was designed to provide the highest correlation with

a given data set and is not intended nor appropriate for application outside

the area of development.

11
REFERENCES

Allaire, P. N., and C. D. Fisher. 1975. Feeding ecology of three sympatric

resident sparrows in eastern Texas. Auk 92(2):260-269.

American Ornithologists' Union. 1983. Check-list of North American birds,

6th edition. American Ornithologists' Union. 877 pp.

Anderson, S. H. 1979. Changes in forest bird species composition caused by

transmission-line corridor cuts. Am. Birds 33(1):3-6.

Best, L. B. 1977a. Nestling biology of the field sparrow. Auk 94(2):308-319.

1977b. Territory quality and mating success in the field

sparrow (Spizella pusilla). Condor 79(2):192-204.

__--;---;---:;=-=-----=-. 1978. Field sparrow reproductive success and nesting ecology.

Auk 95(1):9-22.

__~--=-----,-:--' 1979. Effects of fire on a field sparrow population. Am.

Midl. Nat. 101(2):434-442.

Personal communication (written review comments). Department

of Animal Ecology, Iowa State Univ., Ames, IA 50011.

Buech, R. R. 1982. Nesting ecology and cowbird parasitism of clay-colored,

chipping, and field sparrows in a Christmas tree plantation. J. Field

Ornithol. 53(4):363-369.

Cole, C. A., and R. L. Smith. 1983. Habitat suitability indices for monitoring wildlife populations: an evaluation. Trans. N. Am. Wildl. Nat.

Resour. Conf. 48:(in press).

Crawford, H. S., R. G. Hooper, and R. W. Titterington. 1981. Songbird population response to silvicultural practices in Central Appalachian hardwoods.

J. Wildl. Manage. 45(3):680-692.

Crooks, M. P., and G. O. Hendrickson. 1953. Field sparrow life history in

central Iowa. Iowa Bird Life 23:10-13.

Em 1em, J. T. 1972.

southern Texas.

Size and structure of a wintering avian community in

Ecology 53(2):317-329.

Evans, E. W. 1978. Nesting responses of field sparrows (Spizella pusilla) to

plant succession on a Michigan old field. Condor 80(1):34-40.

Evans, F. C. 1964. The food of vesper, field and chipping sparrows nesting

in an abandoned field in southeastern Michigan. Am. Midl. Nat.

72(1):57-75.

12
Fretwell, S. D. 1969. On territorial behavior and other factors influencing

habitat distribution in birds. III. Breeding success in a local population of field sparrows (Spizella pusilla Wils.). Acta. Biotheor.

19(1):45-52.

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

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

Hebrard, J. J. 1978. Habitat selection in two species of Spizella:

current laboratory and field study. Auk 95(1):404-410.

Johnston, V. R. 1947. Breeding birds of the forest edge in Illinois.

49(2):45-53.

Kahl, R. B., T. S. Baskett, J. E. Ellis, and J. N. Burroughs. 1981.

characteristics of selected nongame birds breeding in Missouri.

Habitat Evaluation Procedures Group, U.S. Fish Wildl. Serv., Ft.

CO. 341 pp.

a conCondor

Habitat

Rpt. to

Collins,

Lanyon, W. E. 1981. Breeding birds and old field succession on fallow Long

Island farmland. Am. Mus. Nat. Hist. Bull. 68(1):1-60.

Martin, A. C., H. S. Zim, and A. L. Nelson.

plants: a guide to wildlife food habits.

500 pp.

1961. American wildlife and

Dover Publ. Inc., New York.

Nolan, V., Jr. 1963. Reproductive success of birds in a deciduous scrub

habitat. Ecology 44(2):305-313.

OINeil, L. J. Personal communication (letter dated 8 July 1983, and phone

conversations). U.S. Army Corps of Engineers, Waterways Experiment

Station, P.O. Box 631, Vicksburg, MS 39180.

Preston, F. W., and R. T. Norris. 1947. Nesting heights of breeding birds.

Ecology 28(3):241-273.

Shugart, H. H., Jr., and D. James. 1973. Ecological succession of breeding

bird populations in northwestern Arkansas. Auk 90(1):62-77.

Stauffer, D. F., and L. B. Best. 1980. Habitat selection by birds of riparian

communities: evaluating effects of habitat alterations. J. Wildl.

Manage. 44(1):1-15.

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. Serv., Washington, DC. n.p.

13
Walkinshaw, L. H. 1936. Notes on the field sparrow in Michigan. Wilson

Bull. 48(2):94-101.

1968. Spizella pusilla pusilla: eastern field sparrow.

Pages 1217-1235 in O. L. Austin, Jr., ed. Life histories of North

American cardinal~ grosbeaks, buntings, towhees, finches, sparrows, and

allies, Part 2. Dover Publ. Inc., New York.

14
50212 '101

REPORT DOCUMENTATION 1. REPORT NO. 2-

PAGE FWS/OBS-82/l0.62 I

'" TItle ana SUllt\tla

Habitat Suitability Index Models: Field sparrow

7. AutIIorlsl

Patrick J. Sousa

9. Pwtorminc Ore-nil.don Nama and Addrea Habi ta t Eva1ua ti on Procedures Group

Western Energy and Land Use Team

U.S. Fish and Wildlife Service

Creekside One Building

2627 Redwing Road

Fort Collins, CO 80526-2899

I%. Soomorinc Orpnizatlon Nama ana Add.... Western Energy and Land Use Team

Division of Biological Services

Research and Development

Fish and Wildlife Service

U.S. Department of the Interior

15. SUlllllemanc.". Not.. WaShl ngton, UC ~U~4U

1

5. R~ O_a

I December 1983

So

So Pwforminc Orpnizlltlon RIClt. No.

10. F"r'ojec:t/Ta.k/Worlr Unit No.

I

(~

(al

Habitat preferences of the field sparrow (Spizella pusilla) are described in this

report, which is one of a series of Habitat Suitability Index (HSI) models. A

review and synthesis of the literature is followed by the development of a habitat ~model for the field sparrow throughout its breeding range in the United States.

HSI models are designed to be used in conjunction with Habitat Evaluation Procedures

previously developed by the U.S. Fish and Wildlife Service.

17. Oocument Anal.,.... a. OescrlDto,..

Mathematical models

Wildlife

Habitability

Birds

e, Identjfla~/Ooan·£nd8<2 l'erms

Habitat Suitability Index

Field sparrow

Spizella pusilla

e. COSATl Field/Grauel

~1.bilitY Statement

I ~elease unlimited

u.s. Government printing Office 1984 - 777-592 & 777-593/9135 & 9136 Reg. 8

19. SecuntY C:us (This "eOOrtl

Unclassified

::0. Sec::utitY Class (This " ....

Unclassified

, Zl. No. at ~"ll"

14

OPTIONAl. FORM 212 ,.....71)

(Forme.ty :-tTI5-3Sl

~eoattr1'ent ,t Commetc.
........ e"/

*Headquarters DIvISion at Biological

SefVIces WashIngton DC

>< Easlern Energy and Land Use Team

Leelown WV

• allonal coasrat EC05y tems Team

Slidell LA

• Weslern Energy and Land use Team

FI Collins CO

• t.ocancos 01 Reg,onal ornces

Habitat suitabi lity index ode Is : 24951

:::::~r:]~I~ill~I~IIIII""I1I""l1r361.till no. 82

,

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61

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Puer to RICO and ...--..,. '--'.. Virgin Islands

. ..,..-

REGION 1

Regional Director

U.S. Fish and Wildlife Service

Lloyd Five Hundred Building, Suite 1692

500 N.E. Multnomah Street

Portland, Oregon 97232

REGION 4

Regional Director

U.S. Fish and Wildlife Service

Richard B. RUSICII Buildina

75 SpringStTeet, S.W.

Atlanta. Georgia 30303

lEGION 2

ReaiotW Director

U~S. Flshand WildUr, SelViee

P.O. Box 1306

Albuquerque. New Mexico 87103

REGION 3

Regional Director

U.S. Fish and WildJifeService

Federal Building. Fort Snelling

Twin Cities, Minnesota 55111
DEPARTMENT OF THE INTERIOR

u.s. FISH AND WILDLIFE SERVICE

loS. .Isn .. WIUH.I..·.: s.-H'\'H ''':

". ./ :\. ,.. ; ....., .,. ,.... ,~

As the Nation's principal conservation agency, th Department of the Interior has responsibility for most of our .natlonally owned public lands and natural resources. This includes

fostering 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 through 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 Istand territories under

U.S. administration.