Guide to Boreal Birds
Bank Swallows originally nested only in steep, sandy riverbanks, but, like other swallows, they have adapted to humans and now nest in the sides of man-made excavations. They breed in colonies of from two or three pairs to a few thousand. Most lay their eggs at the same time and thus later forage for their young at the same time. Such parents have an advantage: Swarms of flying insects are unevenly distributed and are more quickly located when many birds are searching together. The scientific name riparia is from the Latin word for "riverbank."
4 3/4-5 1/2" (12-14 cm). Sparrow-sized; our smallest swallow. Brown above, dull white below; breast crossed by distinct brown band; tail notched. Northern Rough-winged Swallow is warmer brown, with dusky throat and without brown breast band.
Sharp, unmusical pret or trit-trit.
4-6 white eggs in a grass and feather nest in a chamber at the end of a deep tunnel, which it digs near the top of a steep bank. Since it breeds in large colonies, nesting banks may sometimes appear riddled with holes.
Banks of rivers, creeks, and lakes; seashores.
Breeds from Alaska across northern Canada south to California, Texas, and Virginia. Winters in tropics. Also in Old World.