Northern Prairie Wildlife Research Center
Swallows and martins are specially adapted to aerial life and spend more time in daylight flight than all other songbirds. People appreciate swallows and martins because of their insect-eating habits, tameness, and because their arrival signals the presence of spring. North American swallows gather in large flocks during the fall in preparation for migration and can be seen in large numbers perching on utility lines. Members of this family which can be seen in North Dakota include the bank swallow, cliff swallow, rough-winged swallow, tree swallow, barn swallow, and purple martin.
Tree swallows are common in any wooded habitat near water, especially where dead trees are abundant to provide nesting holes. Tree swallows often take advantage of artificial nesting boxes when natural sites are scarce. The female will often line the nest with feathers which she often plucks from other birds. Eggs are white-pink in color and are very small; about 1 inch in length and weigh 1 ounce.
Tree swallows feed on flying insects, but in cold weather can rely on berries and some seeds if insect populations become low. Large colonies will often gather in the fall in large numbers to roost in bushes or reeds of wetlands. Tree swallows are easily recognized by their two-tone coloration and their rapidly repeated call, a liquid "silip-silip-silip".
The barn swallow is the only swallow with deeply forked tail. It will feed on flying insects over fields, ponds, or marshes. The barn swallow can often be seen following farm machinery which stirs-up insects. The barn swallow will nest in colonies, or sometimes singly, and builds the familiar nest that looks like a cup of mud. The female often builds the nest where two walls come together to form a 90-degree angle. Common nest sites include bridges or boat docks, eves of old buildings and even urban dwellings. The nest hardens like cement and is held together by mixing the mud with straw or dried grass. Nesting occurs from April through July and 4-5 eggs are laid which are colored white with brown specks.
The male purple martin is not purple but rather a uniform blue-black which appears entirely black at a distance. It prefers habitat near farms, marshes, forest edges, and urban areas near water. It catches most of its food in flight including mosquitoes, dragonflies, moths, and horseflies. Purple martins will nest in woodpecker holes or other natural cavities among cliffs or rocks. In urban settings, purple martins take advantage of "martin houses", which are large colony nesting boxes placed upon a 15-20 foot pole. Nests are constructed of a wide variety of materials such as leaves, feathers, mud, paper, and even crayfish legs. Breeding season runs from March through July with the female laying 3-7 white eggs.