Keith E. Evans

“ Food: Hairy woodpeckers prefer to feed on insects on dead and diseased trees (Bent 1939) . Approximately 80 percent of the diet is animal matter; adult and larval beetles, ants, and caterpillars are the most frequently eaten items. The primarily insect diet is supplemented with fruit, corn, acorns, hazelnuts, and many other species (Beal 1911, Bent 1939) . The males forage in trees away from the nest for large insects (usually borers) located deep in the wood. Females forage close to the nest on the surface of trees, shrubs, or on the ground for small prey (Kilham 1968a) . ”

“ 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) . ”

“ Habitat: The yellow-bellied sapsucker (sometimes called red-naped) is most abundant along streams in mixed hardwood-conifer forests. It is also found in ponderosa pine, aspen, mixed conifer, lodgepole pine, and in mixed stands of fir-larch-pine.
Nest: Yellow-bellied sapsuckers usually nest in cavities in snags or live trees with rotten heartwood. Aspen seems to be the preferred species (Howell 1952, Lawrence 1967, Kilham 1971) , but nests have also been found in ponderosa pine, birch, elm, butternut, cottonwood, alder, willow, beech, maple, and fir (Bent 1939) . ”

“ Habitat: 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) . ”

“ Habitat: Bewick’s wrens are common and widespread in the West, but uncommon and local in the Appalachians and Ozarks. They are usually found in farmyards, brushlands, fencerows, and suburban areas. Bewick’s wrens are fairly common in the pinyon-juniper forest type, and in mesquite-willow-cottonwood associations along southwestern streams.
Nest: Nests of the Bewick’s wren can be found in a multitude of places. Most nests are cup-shaped and can be either open or closed above. ”

“ Habitat: 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. ”

“ Flickers prefer to nest in open country or in lightly wooded suburban areas where park-like situations are plentiful (Bent 1939) . Conner et al. (1975) reported that flickers usually nest in edge habitats and, in extensive forested areas, nest only in or around openings. Flickers excavate nest holes with a 2.75-inch entrance hole diameter in dead trees or dead limbs of many species of trees including aspen, cottonwood, oak, willow, sycamore, pine, and juniper. ”

“ White-headed woodpeckers usually excavate a new nest cavity every year and often excavate several holes before selecting one to nest in (Bent 1939) . Average nest height is 8 feet above ground.
Food: White-headed woodpeckers feed primarily on pine seeds during the winter and early spring, and on insects during the summer. Tevis (1953) determined that 60 percent of the annual diet was pine seeds and 40 percent was insects. Ants made up half of the insect food; other insects taken were woodboring beetles, spiders, and fly larvae (Beal 1911, Grinnell and Storer 1924, Ligon 1973) . ”

“ Habitat: Barred owls are common in southern swamps and moist river bottoms of the Midwest, and less common but widespread in northern forests. These owls are found in all of the eastern forest types. Although they use white pine, these large owls prefer oak woods and mixed hardwood-conifer stands (Nicholls and Warner 1972) . Preferred oak woods contain dead and dying trees for cavities and are free of dense understory, thus facilitating unobstructed flying and attacking of prey.
Nest: Natural cavities in hollow trees are preferred by barred owls. ”

“ The ash-throated flycatcher is not particularly specific in tree selection as long as it has a cavity. Woodpecker holes, exposed pipes, and nest boxes have been used. Mesquite, ash, oak, sycamore, juniper, and cottonwood are common nest trees (Bent 1942) .
Food: The diet of this species consists mainly of animal material. Beetles, bees, wasps, bugs, flies, caterpillars, moths, grasshoppers, spiders, etc., make up about 92 percent of the diet. ”

“ House wrens are aggressive in their nesting habits and will drive other birds from cavities. Nests have been found in a variety of sites including 2-inch pipes used to brace fence posts, nesting boxes, natural cavities, and downy woodpecker holes (Sutton 1930) . Nests are usually less than 10 feet above the ground. Diameter of the entrance hole in nesting boxes should be 1 inch.
Food: House wrens are capable of eating large quantities of insects and arthropods, which constitute 98 percent of their diet. Animal items include beetles, caterpillars, bugs, grasshoppers, and ants (Bent 1948) . ”

“ Like purple martins, bluebirds have taken advantage of nest boxes provided in areas around farms, near open fields, and in orchards.
Nest: Eastern bluebird nesting sites (snags) are often eliminated because of their unsightliness or interference with cultivation. When available, eastern bluebirds nest in old woodpecker holes, hollows of decayed trees, and crevices of rocks (Pearson 1936) . They will readily take to hollows in wooden fence posts or correctly sized and placed nest boxes (5 × 5 × 8 inches high with a 1.5-inch hole located 6 inches from the bottom) . ”

“ Habitat: This uncommon owl occurs in most old-age conifer associations in the western United States. Forsman (1976) located 123 pairs in Oregon, and 95 percent occupied undisturbed old-growth conifer forests. Karalus and Eckert (1974) described the habitat as being dense fir forests, heavily wooded cliffsides, narrow canyons, and sometimes stream valleys well stocked with oak, sycamore, willow, cottonwood, and alder.
Nest: Forsman (1976) found spotted owls nesting in the holes of living old-growth conifers, particularly Douglas-fir. ”

“ Food: A myriad of insects, including larvae of the gypsy moth and the forest tent caterpillar, beetles, spiders, caterpillars, and ants comprise the main diet of white-breasted nuthatches throughout the spring and summer. In the winter, nearly all food eaten is mast composed of beechnuts, acorns, hickory nuts, maize and sunflower seeds (Bent 1948) . Among the insect foods are several other forest pests including nut weevils, locust seed weevils, and roundheaded woodborers (Scott and Patton 1975) . Nuthatches may also be attracted to feeders with suet and sunflower seeds. ”

“ Natural nest sites seem to be preferred over nest boxes (Planck 1967) . Competition between starlings and native species for nesting cavities usually favors the starling, but most native species seem to breed in some habitats where starlings are not numerous.
Food: Analysis of contents of 2,750 starling stomachs taken in the northeastern states showed 57 percent animal materials such as insects, millipeds, spiders, molluscs, and a few crustaceans. Insects such as weevils, ground beetles, and plant-feeding scarabaeids such as May beetles were especially important. ”

“ One tree may be used for several years, but rarely is a nest hole reused. This behavior provides cavities for other wildlife, including wood ducks, owls, and squirrels (Hoyt 1957) . Timber stands with sawtimber of 15 to 18 inches dbh provide adequate habitat if there is a supply of dead and decaying trees (Conner et al. 1975) .
Food: Insects make up more than 70 percent of the food of pileated woodpeckers. Ants (especially carpenter ants) and beetles are the major food items. In the fall, dogwood berries, wild cherries, acorns, and other wild fruit are included in the diet (Bent 1939) . ”

“ Before constructing a nest, they will generally fill a deep cavity with trash to a level of 12 to 18 inches from the top. They are well known for their habit of including a snake skin in the nest or dangling it from the cavity opening (Bent 1942) .
Food: Food habit studies have shown that great crested flycatchers eat 94 percent animal and 6 percent vegetable material. Most frequently eaten are butterflies, beetles, grasshoppers, crickets, katydids, bees, and sawflies. Vegetable matter is mainly wild fruits. Most food is caught in flight in the usual flycatcher fashion (Bent 1942) . ”

“ Habitat: The sulphur-bellied flycatcher is a common occupant of riparian habitat with sycamore trees in deep canyons from 5,000 to 7,500 feet elevation in the Huachuca Mountains of Arizona.
Nest: Invariably the nest of this species, made from leaf stems (Peterson 1961) , is built in a natural cavity in a large sycamore at a height between 20 and 50 feet above the ground. The cavity normally is a knothole where a large branch has broken off (Bent 1942) . At least one member of each pair may return to the same nest site each year. ”

“ Carolina wrens are quite universal in their choice of nesting sites. These wrens prefer nesting sites that are fairly well enclosed, but they are not totally dependent upon cavities. They are well adapted to habitat conditions provided by man, but also nest in the woods where they prefer tangles and brushy undergrowth. ”

“ For example, removal of some live timber and snags in an Arizona ponderosa pine forest reduced cavity-nesting bird populations by 50 percent (Scott [2] ) . Violet-green swallows, pygmy nuthatches, and northern three-toed woodpeckers accounted for much of the decline. A previously high population of swallows dropped 90 percent, and a low woodpecker population was eliminated. On an adjacent plot, where live trees were harvested but snags were left standing, cavity-nesters increased as they did on a plot where live trees and snags were undisturbed. ”

“ Nest boxes used by captive buffleheads had entrances 27⁄8 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. ”

“ Habitat, cavity requirements, and foods are described for 85 species of birds that nest in cavities in dead or decadent trees. Intensive removal of such trees would disastrously affect breeding habitat for many of these birds that help control destructive forest insects. Birds are illustrated in color ”

“ Food: Insects probably make up a large portion of the diet (Bent 1946) . Telford and Herman (1963) collected 10 birds in the Inyo National Forest, where there was an infestation of lodgepole needle miners and found 639 needle miner caterpillars in chickadee stomachs. Baldwin (pers. comm. [8] ) examined the contents of 17 stomachs from the Wet Mountains, Colorado, and found that 75 percent of the summer diet was insects. Large numbers of spruce aphids were found, as well as flies, beetles, hymenopterans, and other insects. Vegetable material included seeds, spruce buds, and fruits. ”

“ Although trees less than 14 to 16 inches dbh at maturity are too small to yield cavities appropriate for wood ducks, they may be important for smaller species. Aspen, balsam fir, bitternut hickory, ironwood, and other trees fall within this range. Short-lived species such as aspen and balsam fir usually form cavities earlier than longer lived trees. Since a major avenue of fungal infection is sprouts, sprouting vigor and the age at which sprouts are produced are important considerations in managing for cavity-producing hardwood trees. ”

“ As a result, in some areas few nesting sites were left for cavity-nesting birds. Current well-intentioned environmental pressures to emphasize harvesting large dead or dying trees, if realized, would have further adverse effects on such ecologically and esthetically important species as woodpeckers, swallows, wrens, nuthatches, and owls—to name a few. ”

“ Habitat: Chimney swifts are found throughout the eastern half of the United States in wooded and open areas. They have adopted to man-made structures and are no longer dependent upon hollow trees for nesting and roosting. ”

“ 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. ”