Tree swallow
Iridoprocne bicolor
L 5″
Habitat: Tree swallows breed throughout North America from the northern half of the United States north to the limit of tree growth. They are migrants throughout the Central and Southern states and winter primarily in Central America.
Nest: Tree swallows prefer to nest in natural cavities and old woodpecker holes—usually near water. The lack of natural cavities, competition for existing cavities, and the availability of nest boxes, have resulted in a shift in nesting preferences to nest boxes in the eastern United States (Bent 1942, Low 1933, Whittle 1926). Bluebird boxes and purple martin houses are frequently used. Tree swallows are not colonial, but will nest within 7 feet of each other, if there are adequate meadows, marsh, or water area available for feeding (Whittle 1926). Woodpecker holes in aspen, spruce, and pine are the most common nest sites in the West (Bailey and Niedrach 1965).
Food: This species is the first of the swallows to arrive in the north in the spring, and the last to depart in the fall. Because tree swallows can subsist on seeds and berries, they are not as dependent upon insects as are other swallows. They are partial to waxmyrtle and bayberry where these are available. Plant food proportions in the diet are 1 percent in spring, 21 percent in summer, 29 percent in fall, and 30 percent in winter (Martin et al. 1951, Forbush and May 1939).