Breeding: Labrador, west to Alaska, south to Georgia, Alabama, and Mexico. Winter: South America.
Breeding: Farmlands, rural and abundant areas.
Special Habitat Requirements:
Man-made structures, especially buildings, for nesting. Open bars with suitable areas for next construction on beams.
Nesting: Egg dates:
May 11 to August 3, New York. Clutch size: 4 to 6, typically 4 or 5. Incubation period: About 15 days. Nesting period: 16 to 23 days. Broods per year: 1 or 2 (at warmer latitudes). Age at sexual maturity: 1 year. Nest site: Nests inside sheds and barns (often in colonies), under bridges, culverts. Formerly nested on cliffs, in caves and in niches in rocks.
Probably restricted to the nest site. Sample Densities: Usually 6 to 8 nests per site is maximum, but as many as 55 nests have been reported in a single barn 63 at a Lunenburg, Massachusetts barn. 20 pairs per square mile (8 pairs/km2) in favorable habitat in North Dakota. 11 pairs per 100 acres (40 ha) in mixed agricultural and residential habitats including buildings.
Major foods: Flying insects, occasionally takes fruits. Substrate: Air. Techniques: Hawking, skimming water surface. Preferred feeding habitat: Over ponds, lakes, rivers, and fields, seldom feeds more than 0.5 mile (0. km) from nest site.
The diet consists almost entirely of animal matter. Nearly all the food is taken o the wing. Swallow in Illinois spent much time feeding over edge shrub areas. Feeding densities averaged 26 birds per 100 acres (40 ha).