Black-bellied whistling duckHabitat: Black-bellied whistling ducks (tree ducks) are found regularly in southern Texas and erratically elsewhere. Open woodlands, groves or thicket borders where ebony, mesquite, retama, huisache, and several species of cacti are dominant in freshwater habitat are preferred (Oberholser 1974, Meanley and Meanley 1958). Range extensions have been facilitated by flooding and impoundments.

Nest: Natural cavities in trees such as live oaks, ebony, willow, mesquite, and hackberry are preferred, but ground nests and nest boxes are sometimes used. The nest can be over land or water, but herbaceous vegetation under "land-bound" nests may be preferred to brush (Bolen et al. 1964). A perch near the cavity entrance may also be a factor in nest tree selection. Open and closed cavities are used. Nest cavities average 8.7 feet above ground or water and 23 inches deep, with 7.0 x 12.5 inch openings (Bellrose 1976). Nesting boxes should be 11 x 11 x 22 inches high at the front and tapered to 20 inches in the rear, with entrances 5 inches in diameter (Bolen 1967). Nest boxes should not be erected unless they are predator proof.

Food: Black-bellied whistling ducks are predominantly grazers (Rylander and Bolen 1974), but they can dabble and dive for aquatic food. Of 92 percent plant materials, sorghum and Bermudagrass predominated, with smartweeds, millets, water stargrass, and corn also occurring in one study (Bolen and Forsyth 1967). In some areas corn and oats are more important in the diet.

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Wood duckHabitat: Wood ducks are associated with bottomland hardwood forests where trees are large enough to provide nesting cavities and where water areas provide food and cover requirements (McGilvrey 1968). Requirements may be met in several important forest types, all of which must be flooded during the early nesting season: (1) southern flood plain, (2) red maple, (3) central flood plain, (4) temporarily flooded oak-hickory, and (5) northern bottomland hardwoods.

Nest: Optimum natural cavities are 20 to 50 feet above the ground with entrance holes of 4 inches in diameter, cavity depths of 2 feet, and cavity bottoms measuring 10 x 10 inches (McGilvrey 1968). Management for cavities more than a half mile from water is not recommended, and dead trees, other than cypress, do not usually contain usable cavities. Good densities of suitable wood-duck cavities have been recorded for many timber types (Bellrose 1976). Nest boxes are readily used by wood ducks, and their use may increase breeding populations, even if natural cavities are abundant, if predators are excluded. Measurements and placement of wood duck boxes have been well described (U.S. Fish and Wildlife Service 1976, Bellrose 1976, McGilvrey 1968).

Food: Wood ducks consume large quantities of acorns, usually in flooded bottoms. Other mast and fleshy fruits also are eaten, as are waste corn and wheat (Bellrose 1976). Smartweed, buttonbush, bulrush, pondweed, cypress, ash, sweet gum, burweed, and arrow arum seeds are used by breeding birds. Skunk cabbage, coontail, and duckweed are also food items. Duckweed is also habitat for invertebrates in the diet (Grice and Rogers 1965).

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Common goldeneyeHabitat: The breeding range of the common goldeneye generally coincides with the boreal coniferous forest in North America (Johnsgard 1975, Bellrose 1976). In a Minnesota study, 87 percent of breeding goldeneyes were found on large, sandbottomed fish lakes (Johnson 1967), while in New Brunswick, this species preferred water areas with marshy shores and adjacent stands of old hardwoods (Carter 1958). In Maine, nests are found in mature hardwoods adjacent to lakes with rocky shores, hard bottoms, and clear water. Shoal waters less than 10 feet deep with an irregular shoreline provide brood shelter and protective vegetation necessary for duckling food (Gibbs 1961).

Nest: Common goldeneyes used and were more successful in open top or "bucket" cavities than in enclosed cavities in New Brunswick (Prince 1968). Most nests were in silver maples on wetter sites or American elms on drier sites and aspen in northern conifer forests. Nest trees averaged 23 inches in diameter with cavity dimensions of 8 inches in diameter and 18 inches deep; most entrances were 6 to 40 feet above ground (Prince 1968). Wooden nest boxes measuring 12 x 12 x 24 inches with elliptical entrances 31/2 x 41/2 inches were used extensively in Minnesota (Johnson 1967).

Food: Of 395 stomachs examined by Cottam (1939), crustaceans (32 percent), insects (28 percent), and molluscs (10 percent) were primary animal foods (total, 73.9 percent). Crabs, crayfish, amphipods, caddisfly larvae, water boatmen, naiads of dragonflies, damselflies, and mayflies were also found. Pondweed, wild celery, and seeds of pondweed and bulrushes were important plant materials.

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Barrow's goldeneyeHabitat: Barrow's goldeneyes attain their highest breeding population levels in western North America on moderately alkaline lakes of small to medium size in parkland areas. Open water is a necessity throughout the range, but frequently goldeneyes favor a dense growth of submerged aquatics such as sago pondweed and widgeon grass. The abundance of aquatic invertebrates may be more important than nesting cavities in determining distribution (Johnsgard 1975).

Nest: This species is not an obligate tree nester, and has been reported to use holes in banks or lava beds, rock crevices, ground under shrubs and on islands, haylofts, crows' nests, and the outer walls of peat shelters for sheep in Iceland (Harris et al. 1954). However, the usual site is in dead stubs or trees such as aspen, Douglas-fir, and ponderosa pine within 100 feet of water (Palmer 1976). Deserted pileated woodpecker or common flicker cavities enlarged by natural decay are readily used (Palmer 1976). Cavity entrances from 3.0 to 3.9 inches in diameter, cavity depths between 9.8 and 52.9 inches, and cavity diameters between 6.5 and 9.0 inches have been reported (Johnsgard 1975). Nest boxes have been used around high lakes in the Cascade Mountains (Bellrose 1976).

Food: Food of 71 adult Barrow's goldeneyes consisted of 36 percent insects, 19 percent molluscs, 18 percent crustaceans, 4 percent other animals, and 22 percent plants (Cottom 1939). Naiads of dragonflies and damselflies, caddisfly and midge larvae, blue mussels, amphipods, isopods, and crayfish were important animal foods, and pondweeds and wild celery were primary plant foods.

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BuffleheadHabitat: Buffleheads favor small ponds and lakes in open woodlands (Godfrey 1966). In British Columbia, most nesting is in the interior Douglas-fir zone while poplar communities are usually used in Alberta, and ponderosa pine types are preferred in California. Scattered breeding records in Oregon, Wyoming, and Idaho are primarily in subalpine lodgepole pine, and in Alaska (Erskine 1971) Engelmann spruce and cottonwood stands are used for nesting.

Nest: Of 204 nests observed from California to Alaska, 107 were in aspen trees, 44 in Douglas-fir, 14 in balsam poplar and black cottonwood, 12 in ponderosa pine, 11 in poplar, and 16 in a few other coniferous and deciduous trees (Palmer 1976). Buffleheads prefer unaltered flicker holes in aspen. Dead trees close to (within 220 yards) or in water are preferred, and "bucket" or open top cavities are rarely used (Erkskine 1971). Forestry practices that leave stubs near water while clearing away most ground litter and slash that might hinder ducklings from reaching water are to be encouraged. Nest boxes used by captive buffleheads had entrances 2-7/8 inches wide with cavities 7 inches in diameter and 16 inches deep (Johnsgard 1975).

Food: Buffleheads consume mostly animal material. Insects make up 70 percent of summer foods in freshwater habitat. Midge, mayfly, and caddisfly larvae, and naiads of dragonflies and damselflies are also consumed. Water boatmen are the most widely distributed, important food. Plant food was found in many stomachs but much was fiber and was probably taken while catching aquatic insects. Pondweed and bulrush seeds were frequently consumed plant items. Dragonfly and damselfly larvae are important in the diet of ducklings in all areas (Erskine 1971).

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Hooded merganserHabitat: Although hooded mergansers prefer wooded, clear water streams, they also use the wooded shorelines of lakes. Drainage of swamps and river bottoms, removal of snags, and other human activities have been detrimental to this species as they have been to wood ducks. Hooded mergansers are more easily disturbed by man and far more sensitive to a decline in water quality than are wood ducks. Breeding densities often seem more related to food abundance and availability than to nesting cavities (Johnsgard 1975).

Nest: Cavities at any height may be selected in any species of tree; the size and shape of the cavity are apparently not important (Bent 1923). Natural cavities chosen are similar to those used by wood ducks but with smaller optimum dimensions. Frequent use of nest boxes has been reported in Missouri, Mississippi, and Oregon (Bellrose 1976). In Oregon, boxes were placed 30 to 50 feet apart in sets of 8 (Morse et al. 1969). Some of the most southerly nesting records of this species are from wood duck nest boxes (Bellrose 1976).

Food: The food habits of hooded mergansers are not well known, but are apparently more diversified than those of common mergansers. Of 138 stomachs taken from various locations in the United States, rough fishes made up 24.5 percent, game fish and unidentified fish fragments 19.4 percent, crayfish 22.3 percent, other crustaceans 10.3 percent, and aquatic and other insects 13.4 percent (Palmer 1976). Acorns are sometimes eaten in large quantities. Frogs, tadpoles, and molluscs such as snails are also consumed.

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Common merganserHabitat: Common mergansers prefer cool, clear waters of northern boreal or western forests, although at times they have nested as far south as North Carolina and Mexico. Ponds as- sociated with the upper portions of rivers in northern forested regions are often used (Johnsgard 1975). As with hooded mergansers, clear water is needed for foraging.

Nest: Although hollow trees are the usual location, ground nests under thick cover or in rock crevices are not uncommon. A wide variety of other locations have been reported such as chimneys, hawk nests, bridge supports, and old buildings. The species of tree used for nesting and the height of the cavity are apparently unimportant (Foreman 1976). Nest sites are usually close to water (Bellrose 1976) and are used repeatedly, probably by the same female (Palmer 1976). Artificial nest boxes have been accepted, especially in Europe. Preferred dimensions are 9.1 to 11 inches wide, and 33.5 to 39.4 inches high, with 4.7 x 4.7-inch entrances, 19.7 to 23.6 inches above the base of the nest box (Johnsgard 1975).

Food: Programs to reduce populations of this fish-eating merganser have increased trout and salmon production in several areas, at least temporarily. Generally, common mergansers are opportunistic feeders with salmon taken extensively in some areas and suckers, chubs, and eels in others. In warm water areas, food is usually rough and forage fish such as carp, suckers, gizzard shad, perch, and catfish. In some areas, water plants, salamanders, insects, or molluscs may be important in the diet of this species (Palmer 1976).

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Turkey VultureHabitat: Turkey vultures soar over most of the forest types of the United States and southern Canada, with the exception of the pine and spruce-fir stands in the extreme northeastern United States. In search of food this common carrion eater makes use of the forest openings created by roads, powerline rights-of-way, clearcuts, and abandoned fields.

Nest: Preferred nest sites are often at a premium because of the bird's large size and the shortage of large snags. The smell of carrion around the nest necessitates a well-protected site to lessen predator losses. The nest site is almost always at or near ground level (Bent 1937). Although nesting sites are commonly located in hollow trees or hollow logs lying on the ground, these vultures will nest on cliffs, in caves, and in dense shrubbery (Gingrich 1914, Townsend 1914). These birds will return to the same nesting site year after year unless the site has been severely disturbed (Jackson 1903, Kempton 1927).

Food: Turkey vultures are scavengers and carrion-eaters, often hunting along roads where animals have been struck by automobiles. They feed on snakes, toads, rats, mice, and other available animal matter. Often a dozen or more vultures will gather at and feed on a large carcass.

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Black vultureHabitat: The black vulture is found in the southern Great Plains, southeastern pine forests, oak-hickory forests, and intermediate oak-pine forests. It is a more southern species than the turkey vulture.

Nest: Like turkey vultures, black vultures nest under a wide variety of conditions. They use the nest site as found without adding nesting materials (Hoxie 1886, Bent 1937). Hollow stumps or standing trees are favorite nesting sites when they are available; otherwise, eggs are laid on the ground, often in dense thickets of palmetto, yucca, or tall sawgrass (Bent 1937). Nests have been reported in abandoned buildings.

Food: this carrion-eater is often found in towns and cities, feeding on animal wastes, scraps, or garbage. Forests are used primarily for roosting and nesting sites, whereas feeding is usually in more open areas and along highways, where animal carcasses are more plentiful.

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Peregrine falconHabitat: The peregrine falcon is found in tundra regions, northern boreal forests, lodgepole pine and subalpine fir, spruce-fir, southern hardwood-conifer, cold desert shrubs, and prairies ? mainly in open country and along streams. It is also found around salt and freshwater marshes (Fyfe 1969, Hickey and Anderson 1969, Nelson 1969). This species is currently classified as "Endangered" in the United States.

Nest: Although the peregrine falcon is currently considered a cliff-nester, records indicate that it once nested in tree cavities (Goss 1878, Ridgway 1889, Ganier 1932, Bellrose 1938, Spofford 1942, 1943, 1945, 1947, Peterson 1948). The peregrine still uses cavities in broken-off trunks in Europe (Hickey 1942), but the hole-nesting population of America apparently disappeared with the felling of the great trees on which they depended (Hickey and Anderson 1969).

Food: The peregrine falcon feeds primarily on birds ranging in size from mallards to warblers, which are usually stunned or killed in flight. Mammals and large insects form only an insignificant portion of the diet (Bent 1938). White and Roseneau (1970) found remains of fish in the stomachs of peregrines in Alaska, and suggested that fish may be more common in some peregrine diets than the literature indicates.

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MerlinHabitat: The merlin is usually found in open stands of boreal forest, Douglas-fir -- sitka spruce, poplar-aspen-birch-willow, ponderosa pine--Douglas-fir, oak woodlands, and saltwater marshes (Craighead and Craighead 1940, Lawrence 1949, Brown and Weston 1961).

Nest: Like the peregrine falcon, most cavity nests for the merlin were reported before 1910, when it was nesting in cavities of poplars, cottonwoods, and American linden trees (Bendire 1892, Houseman 1894, Dippie 1895). The merlin usually uses tree nests built by other large birds (such as hawks, crows, and magpies) but sometimes nests on the ground under bushes or on cliffs and cutbanks.

Food: Brown and Amadon (1968) found that birds made up 80 percent (by weight) of the food for merlins, insects 15 percent, and mammals 5 percent. Ferguson (1922) examined 298 stomachs and found 4 mammals, 318 birds, and 967 insects. Birds found in the stomachs included small shorebirds, small game birds, and songbirds (which are normally captured in flight). Insect prey consisted of crickets, grasshoppers, dragonflies, beetles, and caterpillars (Bent 1938), while mammals included pocket gophers, squirrels, mice, and bats (Fisher 1893).

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American kestrelHabitat: The American kestrel is the smallest and most common falcon in North America, occurring in open and semi-open country throughout the continent. In the Rocky Mountain region, kestrels are most abundant on the plains, but do nest up to 8,000 feet elevation in the Douglas-fir, ponderosa pine, and pinyon-juniper forest types (Scott and Patton 1975, Bailey and Niedrach 1965). They have been observed on the highest peaks after the nesting season (Bailey and Niedrach 1965).

Nest: Nest sites vary greatly, but kestrels prefer natural cavities or old woodpecker holes. The following nest sites are reported in order of usage: common flicker holes, natural cavities, cavities in arroyo banks or cliffs, buildings, magpie nests, and man-made nesting boxes (Bailey and Niedrach 1965, Bent 1938, Roest 1957, Forbush and May 1939). Nest boxes, approximately 10 x 10 x 15 inches, should be located 10 to 35 feet above ground with a 3-inch entrance hole. Natural cavities or nest boxes should be available along edges of forest openings (Bailey and Niedrach 1965, Hamerstrom et al. 1973, Pearson 1936).

Food: Kestrels hunt from high exposed perches overlooking forest openings, fields, or pastures. Food consists primarily of insects (often grasshoppers), small mammals, and an occasional bird (Bent 1938).

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BArn owlHabitat: The barn owl inhabits most of the forest types in the United States except the higher elevation types in the Rocky Mountains. They are usually considered uncommon residents because their silent nocturnal habits render them undetectable by most casual observers. Barn owls are also birds of the open country, and adapt readily to areas occupied by man (Marti 1974).

Nest: Before the coming of man, barn owls nested in natural cavities in trees, cliffs, or arroyo walls, but now they also nest in barns, church steeples, bird boxes, mine shafts, and dove-cotes (Bailey and Niedrach 1965, Reed 1897).

Food: Barn owls frequent areas where small mammals are plentiful; mice, voles, rats, gophers, and ground squirrels are major food items. Birds other than those such as house sparrows and blackbirds, which have communal roosts, are only rarely taken (Marti 1974).

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Screech owlHabitat: This small owl is found in most forest types below 8,000 feet elevation throughout the United States. Screech owls prefer widely spaced trees, interspersed with grassy open spaces, for hunting. Meadow edges and fruit orchards are favored throughout the eastern United States.

Nest: Like other owls, the male screech owl defends a nesting and feeding territory. Maples, apples, and sycamores with natural cavities or pines with woodpecker holes are preferred in the East (Bent 1938). Along the drainage systems of the plains areas, natural cavities or common flicker holes in cottonwood trees are preferred (Bailey and Niedrach 1965). Nest boxes in orchards or residential areas are often used. Hamerstrom (1972) recommended a nesting box 8 x 8 x 8 inches with a 3 inch entrance hole.

Food: Screech owls are among the most nocturnal owls and are rarely seen feeding. Major food items are mice and insects. Fisher (1893) examined 255 stomachs of screech owls and found birds in 15 percent of them, mice in 36 percent, and insects in 39 percent. Korschgen and Stuart (1972) found mostly small mammals in 419 screech owl pellets from western Missouri. The volume of the screech owl pellets was predominantly meadow mice, white-footed mice, and cotton rats.

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Whiskered owlHabitat: The small whiskered owl is generally found in the dense oak or oak-pine forests of southern Arizona, southwestern New Mexico, and into Mexico.

Nest: Nests have been reported in both natural cavities and old woodpecker holes located in oak, cottonwood, willow, walnut, sycamore, and juniper trees (Bent 1938). Karalus and Eckert (1974) suggest that white oak is one of the favorite nest sites, and that these small owls prefer to nest in cavities in the limbs of trees rather than in the trunk.

Food: Black crickets, hairy crickets, moths, grasshoppers, large beetle larvae, and centipedes are the principal elements of the diet (Jacot 1931). In addition to those mentioned by Jacot, Karalus and Eckert (1974) list praying mantids, roaches, cicadas, scorpions, and small mammals as part of the diet.

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