pileated woodpecker are found in mature hardwood stands dominated by sugar 

 maple ( Acer saccharum ) , American beech ( Fagus grandifolia ) , and yellow birch 

 ( Betula allegheniensis ) ; the northern hardwoods. 



Mixed forests . Bird species associations in mixed forests are difficult 

 to characterize because of the intermixing of spruce-fir, pine, and deciduous 

 forest bird communities. Species composition and relative abundance vary in 

 proportion to preferred vegetation types. Mixed stands often have a greater 

 diversity of bird species because of the combination of species adapted to 

 each type. Approximately 53 species are found in mixed forests: 29 breeding 

 residents, 20 permanent residents, 3 winter residents, and 1 migratory 

 resident (tables 16-1 through 16-4). 



Rural and Developed Land 



Over 70 species of birds are found in habitats described as rural, suburban, 

 or urban. Many of these species are successional and edge species. Thirty- 

 five are breeding residents, 27 are permanent residents, 8 are winter 

 residents, and 3 are migratory residents. Highly urbanized areas are 

 dominated by 3 introduced species: starling, house sparrow, and rock dove or 

 pigeon. The density of urban birds is often as high as in forested habitats 

 because of the abundance of these 3 species (Erskine 1977). Bird species 

 commonly found in rural or suburban areas include song sparrows, northern 

 orioles, warbling vireos, house wrens, chipping sparrows, mockingbirds, 

 mourning doves, swallows, chimney swifts, crows, blue jays, robins, yellow and 

 chestnut-sided warblers, American redstarts, red-eyed vireos, and gray 

 catbirds, among others (figure 16-1). 



ABUNDANCE OF TERRESTRIAL BIRDS 



The abundance of terrestrial birds is affected by several factors, including 

 abundance of preferred habitats, food supply, weather, and predation (see 

 "Factors Affecting Distribution and Abundance" below) . On a local scale bird 

 populations have been determined on small areas (<100 acres; <40 ha) by spot- 

 mapping, which estimates the number of breeding pairs on a unit of land 

 (Robbins 1970) . The effects of various land use practices on breeding bird 

 populations can be assessed using this method. 



On a regional scale long term trends in the relative abundance of birds are 

 determined with index counts of breeding (Breeding Bird Survey) and wintering 

 (Christmas Bird Counts) birds. While these index counts cannot be used to 

 predict the bird populations on any particular area, they can point out 

 significant increases or decreases in the abundance of bird species which can 

 then be examined more closely. Additional surveys have been made to determine 

 the abundance of bald eagles and ospreys in coastal Maine. Information on the 

 bald eagle is contained in a special case study at the end of this chapter. 

 The relative abundance of each species of terrestrial bird found along the 

 Maine coast is given in tables 16-1 through 16-4. 



16-19 



10-80 



