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HABITAT SELECTION, SUCCESSION, AND BIRD COHMUNITY ORGANIZATION
Stanley H. Anderson
Higratory Bird and Habitat Research laboratory
U.S. Fish and Wildlife Service laurel, HD 20811
ABSTRACT
Nongame bird community management is suggested based on habitat selection, plant succession, and bird community organization.
Suggested forms of stratification of habitat are examined.
Factors that indicate habitat selection and bird community organization are shown by means of discriminant function analysis, principal component analysis, and factor analysis. Factors such as habitat size, habitat structure, water impoundment, and edge are related to nongame bird communities.
KEYWORDS: habitat selection, bird community, nongame bird management, stepwise multiple regression, discriminant function analysis, principal component analysis, factor analysis.
INTRODUCTION
EffeGtive management of birds means effective habitat management. rmbitat is a term applied to the area where all requisite needs for a species are found. Typically, biologists state that .;_nimals "select" their habitat; however, this is not an accurate statement because animals have coevolved with the biotic and abiotic components of an ecosystem. Since there are many variations in the physical environment, many different living assemblages evolve. These groups of organisms then provide their own dynamic structure to the community, which creates further variation in the types of ha bi tat.
Bird species are usually found in habitats where their shelter, feeding, and social needs are satisfied which means that some species are found in more than one habitat type. Thus, for example, chickadees nest in forests but move through forest, edge, and savannah-like habitat to feed.
Furthermore, one must realize that habitat used by birds differs during each season. During the breeding season, concentrations of residents and breeding migrant species defend territories in their breeding habitat. In the fall, most nonbreeding migrants and resident species are found in a variety of habitats. Resident species appear to be more nomadic than during the breeding season, whereas nonbreeding migrants may be flocking and simply stopping for a short period of time.
In the winter, many North American habitats have mixed flocks of permanent resident and winter resident species, which move through several habitats seeking food.
In each community, birds have evolved characteristics that allow them to survive. Individual species may have minor variations in different community types.
For example, food of the nuthatches found near the Williamette Valley in Oregon differs during the spring, fall, and winter seasons. Likewise, bill size of nuthatches in the forests of the Coast Range differs from that of populations living in the-forests of the Cascades (Anderson 1976). Such differences might result in part from structural variation in habitat; however, they are also related to the different species assemblages that are found in different communities.
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The present paper examines a technique for looking at the stratification of habitat as the basis for discussion. Examples of methods used to determine habitat features associated with individual species are given. Finally, community changes known to be associated with changes in bird populations are discussed and related to the management of nongame birds.
STRATIFICATION
To effectively manage birds in different communities it is necessary to have some form of subdivision or stratification of the environment into ecoregions in order to associate bird communities with habitat structure and successional stages.
At the Migratory Bird and Habitat Research Laboratory, we have developed a stratification based in part on results of the Breeding Bird Survey (Fig. 1).
The method behind stratification was that each species of bird has its own geographic limits and within these limits are several zones of abundance representing availability of suitable habitats. In mountainous areas, there occur discrete zonal boundaries to vegetation types that result from differences in temperature, precipitation, or wind speed. Typically the abundance of many species of birds changes abruptly across such boundaries. In flat country, boundaries are more obscure and in many instances very irregular, often extending for miles along a stream valley where differences in soil type or moisture support habitats not found a short distance on either side of the stream.
Because bird distribution and abundance, particularly in the breeding season, is so strongly influenced by habitat the use of ecological rather than political boundaries is most logical. Ecological boundaries are based largely on John Aldrich's
(1963) map of Life Areas of North America, developed for his paper on Geographic
Orientation of American Tetraonidae. There have since been many minor adjustments in strata boundaries. Such refinements in the United States have come largely from
"Physiogeography of Eastern United States" (Fenneman 1938), "Natural Land Use Areas of the United States" (Ma.rsckner 1933), "Potential Natural Vegetation" (Kuchler
1965), and various publications for individual states. Canadian boundary refinements have come from Dr. A. J. Erskine of Canadian Wildlife Service and from published maps of individual provinces.
The name of each stratum as defined by Breeding Bird Survey (BBS) data is shown in Table 1.
These strata are grouped into eight larger regions which contain broadly similar habitat types. The regions are as follows:
1 Southeastern Mixed Forest
2 - Eastern Deciduous Forest
3 - Northern Coniferous Forest
4 - Prairie and Plains
5 - Western Mountains
6 - Pacific Slope
7 - Arid Interior
8 - Tundra
In the western part of the United States, for example, we can see that the
Great Plains, Western Mountains, Arid Interior, and Pacific Slope are each broken down into several distinctive BBS strata.
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TABLE i.--Breeding Bird Survey Strata (1979).
SOUTHEASTERN MIXED FOREST
01 Sub-tropical
02 Floridian Section
03 Lower Coastal Plain
04 Upper Coastal Plain
OS Hississippi Alluvial Plain
06 West Gulf Coastal Plain
07 Nueces Plain
08 Glaciated Coastal Plain
EASTERN DECIDUOUS FOREST
10 Northern Piedmont
11 Southern Piedmont
12 Southern New England
13 Ridge and Valley
14 Highland Rim
15 Lexington Plain
16 Great Lakes Plain
17 Wisconsin Driftless Area
18 St. Lawrence Plain
19 Ozark-Ouachita
20 Great Lakes Pine Belt
PRAIRIE AND PLAINS
31 Till Plains
32 Dissected Till Plains
33 Osage Plains
34 High Plains Border
35 Staked Plains-Pecos Valley
36 High Plains
37 Prairie Pothole Section
38 Hissouri Plateau-Glaciated
39 Missouri Plateau-Unglaciat~d
40 Black Prairie
53 Edwards Plateau
54 Colorado Plateaus & Canyonland
WESTERN l10UNTAINS
61 Black Hills
62 Southern Rocky Hountains
63 High Plateaus of Utah
64 Central Rocky ~fountains
65 Dissected Rockies
66 Sierra-Trinity Hountains
67 Cascade Mountains
68 Canadian Rockies
NORTHERN CONIFEROUS FOREST
21 Cumberland Plateau
22 Kanawha Plateau
23 Blue Ridge Mountains
24 Allegheny Plateau
25 Open Boreal Forest
26 Adirondack Hountains
27 Northern Hardwoods
28 Spruce-Hardwood Forest
29 Closed Boreal Forest
30 Aspen Parklands
ARID INTERIOR
81 Hexican Highlands
82 Southern Sonoran Desert
83 Northern Sonoran Desert
84 Pinyon-Juniper Woodland
85 Klamath-Pitt Plateau
86 Wyoming Basin
88 Great Basin
89 Columbia Plateau
PACIFIC SLOPE
91 Central Valley
92 California Foothills
93 Southern Humid Coastal Belt
94 Northern Humid Coastal Belt
95 Southern California Mountains
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HABITAT ASSOCIATIONS OF NONGAME BIRD SPECIES
Statistical Techniques
Birds can be observed in a variety of habitat types. In order to develop species management plans, it is necessary to explain which features of the habitat are associated most frequently with each species of bird. A number of different techniques have been tested to associate birds with habitat structure. These range from a quantitative description of the vegetation and physical environment to statistical analyses showing which particular features are associated with each bird species. It is always necessary to sample bird abundance and determine habitat factors that are related to the avian community. The following are a few of these techniques, showing how they relate to community management practices.
Stepwise multiple regression, which uses the abundance of bird species as dependent variables and habitat measurements as independent variables in a regression equation, can be used to indicate which of the habitat variables can best be used to predict bird species abundance (Sturman 1968, Robbins 1978). The variables are added into a regression equation in the order in which they increase the multiple correlation coefficient. The variable that most reduces the residual variation in species abundance around the least squares regression line is added first; the variable that most reduces the variation when considered with the first variable is added second; the third variable considered in conjunction with the first two which most reduces the variation is added next; and so on (Barr et al. 1976). Habitat variables continue to be entered into the equation until no more significant reduction in variation is possible. Thus, a different number of variables acting together are significantly correlated with each bird species.
In the Oregon white oak
~tands the Black-capped Chickadee 1/ was shown by stepwise multiple regression to be associated with the number of trees per acre taller than 60 feet, canopy volume per acre, the DBH, the total canopy cover, and the amount of space (distance between trees) (Anderson 1970). The White-breasted
Nuthatch in these forest stands was associated with the length of secondary branches coming off the rna jor branches in the tree, the total amount of vegetation in the upper layer, and the distance between trees. In Douglas-fir forests, the Chestnutbacked Chickadee was associated with the amount of space found between the trunk of the tree and the foliage, the type of bark, the number of dead twigs, and the total trees per acre. The Red-breasted Nuthatch in Douglas fir was associated with canopy volume, canopy cover, the number of snags, and the number of trees taller than 60 feet. By comparison, the Brown Creeper, which was found in both the_ oak and fir, was associated with the same four factors in each habitat; in ;the oak forest the sequence was: the distance between the trunk of the tree and the branches, the total trees per acre, the distance from the ground to the top of the trunk, and the average height of trees. In the conifers, the sequence of the last two factors was reversed.
Another technique that has been useful in determining the relationship between bird species and habitat structure is discriminant function analysis (Anderson and
Shugart 1974, Bertin 1977, Noon in press). Stepwise multiple regression deals with the interdependence of variables and each variable is dependent on how much it in combination with the other variables reduces the residual variation in abundance around the regression line. Discriminant function analysis selects a subset of habitat features which best distinquishes habitats of two or more species. If the groups in the analyses are based on the presence or absence of a particular bird
1/See Appendix I for scientific names of bird species discussed in paper.
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species, specific habitat requirements may emerge. In a study in an east Tennessee forest, Anderson and Shugart (1974) found the White-breasted Nuthatch to be associated with total amount of foliage and branches, biomass of trees 1.2 to 8.4 em
DBH, while Downy Woodpeckers were associated with the total number of saplings present.
Habitat Use
Biologists recognize that specific habitat features of the forest can be associated with different bird species and thus provide information necessary to manage that species. Biologists also must realize that within the community birds use habitats in different ways. For example, both vertical and temporal stratification occur in a breeding bird community in a forest system (Anderson et al. 1979).
When species comparisons are made, it is possible to show how different periods of activity or different forms of vertical stratification permit birds to use communities in different manners. Cody (1968) discussed how horizontal, vertical, and temporal habitat selection and food specialization allow species to coexist in different communities.
Habitat features, as well as species behavior patterns, can be used to discuss specific forms of habitat selection and bird distribution. Noon (in press) showed how a guild of five thrush species that are sympatric on large mountains in the northeastern United States had distinct distribution patterns along elevation gradients. Guild composition and distributions shift with changes in the habitat as one moves southward along the Appalachian Mountain chain. Thus the natural evolution and turnover of plant communities along the mountain gradient has resulted in variation in bird species occupying that gradient.
Succession
Community succession and bird populations respond to natural shifts in structure of avian habitat. In previous discussion I showed that changes in the total canopy volume, the degree of openness, or other features of the habitat result in changes in populations of birds because the features with which they are associated may no longer be present. This type of study in a successional sequence provides an example of the use of community types in managing nongame bird populations.
In western Oregon, natural successional sequence moves from an open oak savannah to a dense oak forest into the more coniferous Douglas-fir (Fig. 2). In the Oregon white oak, the Black-capped Chickadee, White-breasted Nuthatch, Bewick's Wren,
Bushtit, Orange-crowned Warbler, lhcGillivray's Warbler, and Wilson's Warbler are common. Looking at the coniferous forest, we find that Chestnut-backed Chickadee,
Red-breasted Nuthatch, Brown Creeper, Winter Wren, Hermit Warbler, Western Tanager, and Oregon Junco are the more common species (Tables 2 and 3).
Thus studies of succession indicate that there are distinct groups of birds associated with each type of community in each successional sequence. Overlap occurs as different seral stages are reached; however, to maintain a good variety of nongame communities it is necessary to have representatives of each stage. Frequently human disturbance adds to habitat diversity and allows managers to better maintain a series of communities. Thus fire, logging, and brush clearing projects can all be planned in the context of natural succession.
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TABLE 2.--Twelve most common breeding bird species of Oregon white oak.
Black-capped Chickadee
Bushtit
White-breasted Nuthatch
Brown Creeper
American Robin
Orange-crowned Warbler
HacGillivray' s Warbler
Wilson's Warbler
Rufous-sided Towhee
Oregon Junco
Chipping Sparrow
Golden-crowned Sparrow
TABLE 3.--Twelve most common breeding bird species of Douglas-fir (Oregon).
Hairy Woodpecker
Steller's Jay
Chestnut-backed Chickadee
Red-breasted Nuthatch
Brown Creeper
Winter Wren
Hermit Warbler
MacGillivray's Warbler
Wilson's Warbler
Western Tanager
Rufous-sided Towhee
Oregon Junco
COt1~1UNITY ORGANIZATION
Studies of energy flow, biomass levels, and species interaction can be undertaken at the community level. Actual management of a community is often difficult because most of the data on avian habitat needs are available on the species level.
By combining all habitat species information, it is possible to view bird species in relation to one another and to selected environmental characteristics.
Principal component analysis is one technique used for viewing information simultaneously for all species (Seal 1964). Thus, for example, Anderson and Shugart
(1974) reduced the information contained in 28 correlated habitat variables (dimensions) to 3 uncorrelated principal components. By positioning each species within the 3-dimensional space, it was possible to show how each bird species related to the mean habitat vector or mean available habitat. Management implications could be drawn from understanding how habitat disturbances would shift the mean habitat vector relative to the positions of particular species in this space.
Smith (1977) demonstrated that habitat variables could be combined into principal components and bird species ordinated along each axis. Combining the results of discriminant and principal component analyses, he suggested that moisture gradients and tree size could be used to separate avian habitat niches.
Factor analysis is a statistical technique that can be used to reduce several habitat variables in a multidimensional space. It is similar to principal component
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analysis; however, in factor analysis factors are scaled so that coefficients are the correlation coefficients with the original measurements. Factors can then be rotated to make them more interpretable biologically (see Overall and Klett 1972).
With this tool it is possible to reduce habitat variables to different factors and determine gradients of habitat or behavior attributes that influence avian communities. Anderson (1979) showed how three factors could be used to separate burned and unburned plots in a northern Hichigan forest. The first factor represented forest maturity; the second, effect of burn; and the third, shrub cover.
Holmes et al. (1979) used factor analysis to examine similarities and differences of foraging patterns of birds in a New Hampshire forest. Key factors were foraging height, foraging location within the canopy, and differential use of tree species and foraging substrate.
Both principal component analysis and factor analysis assist in identifying key habitat components necessary for the existence of the bird community. These data need to be compiled and refined for each avian stratum to allow managers to use community attributes for managing nongame birds.
HANAGEHENT FACTORS
A number of specific attributes exist that managers can use to maintain nongame bird communities. These factors include total size of habitat, structure of habitat, streams or water impoundments, and the maintenance of edge.
One of the most important components in maintaining breeding bird communities is extent of contiguous habitat. Most data on this subject have been assimilated from forest bird community studies (Robbins 1979). In six study sites around Maryland, Robbins' data from up to 30 years show a major decline in species of long distance migrants (Table 4). The permanent residents, on the other hand, tend to maintain their population despite suburban sprawl and forest fragmentation. The short distance migrants that have adapted to survival in edge habitat, such as jays,
House Wrens, catbirds, robins, Starlings, blackbirds~and towhees, also preserve their populations. To maintain communities of breeding birds, Robbins recommended that forests be managed in such a way that large tracts of contiguous canopy (2,500 acres and more) be intact at all times. He suggested that forest management plans be coordinated to retain such tracts of woods.
TABLE 4.--Populations of some bird species that have declined in the
Maryland--Washington, DC region (1947-1978) (Robbins 1979).
Yellow-billed Cuckoo
Ruby-throated Hummingbird
Eastern ~Jood Pewee
Yellow-throated Vireo
Black-and-white Warbler
Worm-eating Warbler
Northern Parula Warbler
Ovenbird
Louisiana Waterthrush
Kentucky Warbler
Hooded Warbler
American Redstart
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Host of the habitat variables correlated with bird species are components of habitat structure. Foliage height profiles can be correlated with bird species diversity (HacArthur and HacArthur 1961). Such data indicate that the structural aspect of the habitat is an important feature that can be used for managing nongame birds. When biologists examine different successional seres they are actually talking about changes in structure that influence the bird community. Community structure can be altered by logging, fire, and human development. This means that some form of predictive equation can be developed to show how this form of structural alteration, which is in effect an abrupt change of the community to a different successional sere, can be used to predict avian changes. Such predictions need to be developed for each community type which falls within the stratified zones listed earlier in this paper.
Water is another component of the community that can be used to attract· some nongame birds. Although impoundments have been used to attract migrating waterfowl and provide areas in marshes for nesting birds, many nongame birds can also be maintained by streams, small ponds, lakes, and marshes. In this situation it is necessary to determine the types of populations that can be associated with each size and type of aquatic habitat. In some situations riparian forests develop along waterways. Their structural differences, as well as proximity to the food or water and insects attracted to this area, provide opportunities for different bird communities to survive. In the Jackson Hole area of Wyoming and other places in the mountain states, dense groves of aspen develop in the riparian habitat due to available water. Although aspens are also found on mountainsides and valleys, the aspen forests along the riparian habitat have a unique structure and provide ideal communities for breeding cavity-nesting species. The distinction that exists between these riparian habitats in the Jackson Hole area and surrounding forests can be easily seen in Tables 5, 6, and 7.
TABLE 5.--Twelve common bird species of riparian aspen community--
Jackson Hole, Wyoming.
Red-shafted Flicker
Hairy Woodpecker
Downy Woodpecker
Western Wood Pewee
Tree Swallow
Black-capped Chickadee
Hountain Bluebird
Warbling Vireo
Yellow Warbler
Black-headed Grosbeak
White-crowned Sparrow
Lincoln's Sparrow
TABLE 6.--Common bird species of lodgepole pine community.
Red-shafted Flicker
Downy Woodpecker
Gray Jay
Mountain Chickadee
Hermit Thrush
Audubon's Warbler
Oregon Junco
Chipping Sparrow
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TABLE 7.--Twelve common bird species of spruce forest community.
Hairy Woodpecker
Clark's Nutcracker
Mountain Chickadee
Red-breasted Nuthatch
Brown Creeper
American Robin
Townsend's Solitaire
Ruby-crowned Kinglet
Cassin's Finch
Pine Grosbeak
Pine Siskin oregon Junco
Another feature useful in maintaining nongame bird communities is edge (Lay
1938). Edge is especially important to bird populations, as has been shown in studies listing a greater number of bird species in areas of mixed habitat found at the edge of two plant communities (Johnston 1947).
Gates and Gysel (1978) indicated in a study of fledging success in forest ecotones that each bird species seems to have a preferred distance from the habitat discontinuity or the edge. They found that over half of the nests were within 15 m of the edge, of which a large number belonged to birds characteristic of mixed breeding habitat.
Whereas edge is a concept for managers to recognize and use, it can be overemphasized. Thus, when looking at the positive effects of transmission-line corridors, some individuals speak of the increased edge. This information must be taken into context of the total community size. Many birds characteristic of forest int~rior habitats are unable to maintain their populations in the vicinity of edge habitats (Robbins 1979). If a transmission-line corridor, roadway, or other opening in a forest results in decreasing that forest's area to a size below which the normal community can survive, then it may have an adverse impact.
HANAGEHENT IMPLICATIONS
Managers have a variety of information currently available to consider in maintaining nongame bird communities. Many additional questions, however, remain to be answered. Although I have spoken of the total extent of habitat, I can point out that to maintain most nongame communities it is important to keep not only a mature plant community but also a variety of successional seres. Some forms of controlled human disturbance can therefore be an important component of management, if they tend to create a diversity of habitat types of sufficient size.
Nongame bird communities can be managed as a secondary objective on a tract of land. When features associated with bird communities are known, foresters, range managers, and wildlife managers can use this information to maintain bird communities on land where specific goals are clearly defined. Thus, foresters can utilize timber practices to coincide with the total size of forest necessary to maintain bird communities. Occasional snags can be left standing for cavity nesters. Care should be used in considering this option, however, because as Robbins (1979) points out, excessive retention of snags can create an adverse impact due to disease and perch sites for cowbirds.
Overall, wildlife managers need to clearly state the objectives they are seeking and then utilize sound habitat information to manage the nongame bird community.
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Biologists need to define basic units of habitat and prescribe major features of the environment necessary to maintain nongame communities for each ecoregion and successional stage.
ACKNOWLEDGMENTS
I appreciate the helpful suggestions offered by Chandler Robbins and Barry
Noon. Janet Partelow prepared the illustrations. Barbara Dowell and Romell
Decker typed the manuscript.
REFERENCES
Aldrich, J. w.
1963. Life areas of North America. J. Wildl. Manage. 27:530-531.
Anderson, S. H.
1970. Ecological relationships of birds in forests of western Oregon. Unpubl.
Ph.D. Thesis, Oregon State University. 121 p.
Anderson, S. H.
1976. Comparative food habits of Oregon nuthatches. Northwest Science 50:213-221.
Anderson, s. H.
1979. Habitat structure, succession and bird communities. In R, H. DeGraaf and K. E. Evans, eds. Workshop Proceedings, Management of north central and northeastern forests for nongame birds. U.S. Forest Service, St. Paul, MN. p. 9-21.
Anderson, S. H. and H. H. Shugart.
1974. Habitat selection of breeding birds in an east Tennessee deciduous forest.
Ecology 55:828-837.
Anderson, S. H., H. H. Shugart and T. H. Smith.
1979. Vertical and temporal habitat utilization within a breeding bird community.
In Dickson et al., ed. The role of insectivorous birds in forest ecosystems.
Academic Press. p. 203-216.
Barr, A. J., J. H. Goodnight, J.D. Sall, and T. T. Helwig.
1976. A User's Guide to SAS-76. SAS lnst., Raleigh, NC. 329p.
Bertin, R. I.
1977. Breeding habitats of the Wood Thrush and Veery. Condor 79:303-311.
Cody, M. L.
1968. On the methods of resource division in grassland bird communities. American
Naturalist 102:107-147.
Fenneman, N. M.
1938. Physiogeography of Eastern United States. McGraw-Hill Book Co., New York.
Gates, J. E. and L. W. Gysel.
1978. Avian nest dispersal and fledging success in field forest ecotones. Ecology
59:871-883.
Holmes, R. T. and R. E. Bonney, Jr. and S. W. Pacala.
1979. Guild structure of the Hubbard Brook Bird Community: a multivariate approach. Ecology 60:512-520.
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Johnston, V. R.
1947. Breeding birds of the forest edge in east-central Illinois. Condor 49:45-53.
Kuchler, A. W.
1965. Potential natural vegetation. U.S. Geological Survey. Washington, D.C.
Lay, D. W.
1938. How valuable are woodland clearings to wildlife? Wilson Bull. 50:254-256.
MacArthur, R. H., and J. W. MacArthur.
1961. On bird species diversity. Ecology 42:594-598.
Marsckner, F. S.
1933. Natural land-use areas of the United States. Bureau of Agricultural
Economics, USDA, Washington, D.C.
Noon, B. R.
(in press). gradient.
The distribution of an avian guild along a temperature-elevation
The importance and expression of competition. Ecological Monographs.
Overall, J. E. and C. J. Klett.
1972. Applied multivariate analysis. McGraw-Hill, New York. 500 p.
Robbins, C. S.
1978. Determining habitat requirements of nongame species. Transactions of the
North American Wildlife and Natural Resources Conference 43:57:68. Published by the Wildlife Management Institute, Washington, D.C.
Robbins, C. s.
1979. Effect of forest fragmentation on bird populations. In R. M. DeGraaf and
K. E. Evans, eds. Workshop Proceedings, ~funagement of north central and northeastern forests for nongame birds. U.S. Forest Service, St. Paul, MN. p. 198-
213.
Seal, H. L.
1964. Multivariate statistical analysis for biologists. Wiley, New York.
Smith, K. G.
1977. Distribution of summer birds along a forest moisture gradient in an Ozark watershed. Ecology 58:810-819.
Sturman, W. A.
1968. Description and analysis of breeding habitats of the chickadees, Parus atricapillus and
rufescens. Ecology 49:418-431.
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Common Name
Yellow-billed Cuckoo
Ruby-throated Hummingbird
Red-shafted Flicker
Hairy Woodpecker
Downy \Joodpecker
APPENDIX I
Eastern Wood Pewee
Western \Jood Pewee
Tree Swallow
Gray Jay
Steller's Jay
Clark's Nutcracker
Black-capped Chickadee
Hountain Chickadee
Chestnut-backed Chickadee
Bushtit
White-breasted Nuthatch
Red-breasted Nuthatch
Brown Creeper
House Wren
Winter Wren
Bewick's Wren
American Robin
Wood Thrush
Hermit Thrush
Veery
Uountain Bluebird
Townsend's Solitqire
Ruby-crowned Kinglet
Starling
Yellow-throated Vireo
Warbling Vireo
Black-and-white Warbler
\vorm-ea ting Warbler
Orange-crowned Warbler
Northern Parula Warbler
Yellow Warbler
Audubon's Warbler
Hermit Warbler
Ovenbird
Louisiana Waterthrush
Kentucky Warbler
MacGillivray's Warbler
Hooded Warbler
Wilson's \va rbler
American Redstart
Western Tanager
Black-headed Grosbeak cassin' s Finch
Pine Grosbeak
Pine Siskin
Rufous-sided Towhee
Oregon Junco
Chipping Sparrow
White-crowned Sparrow
Golden-crowned Sparrow
Lincoln's Sparrow
Scientific Name
be~ickii
ve~ivorus
26