Feeding Behavior

Forages almost entirely in the air. May forage very low over water, or quite high at times. Occasionally walks about on ground to pick up insects, perhaps mostly in harsh weather.

Eggs

4-5, sometimes 3-8. White. Incubation is by female, 15-18 days. Young: Both parents feed nestlings. Young leave nest about 26-31 days after hatching.

Young

Both parents feed nestlings. Young leave nest about 26-31 days after hatching.

Diet

Insects. Feeds on a wide variety of flying insects, including many wasps and winged ants, and some bees; also many true bugs, flies (including house flies and crane flies), beetles, moths, and butterflies. Dragonflies may be an important part of diet. Also eats some spiders. The old claim of martins eating "2,000 mosquitoes a day" apparently has no basis in fact.

Nesting

Males return to nesting areas first in spring, establish nesting territories. Usually nests in colonies, especially in east, where almost all are in multiple-roomed nest boxes put up for them. Western martins may nest in looser colonies or as isolated pairs. Male will sometimes have more than one mate. Nest: Natural sites are in cavities, mostly old woodpecker holes, in trees (or in giant cactus in southwest). In the east, most martins now use nest boxes. Sometimes nests in holes in buildings or cliffs. Nest (built by both sexes) is cup of leaves, grass, twigs, debris, and usually mud. Nest may have raised dirt rim in front to help keep eggs from rolling out.