The Sand Martin, Riparia riparia, is a migratory passerine* bird in the swallow family. It has a wide range in summer, taking up practically the whole of Europe and the Mediterranean countries, part of northern Asia and also North America, where it is called Bank Swallow. It winters in eastern and southern Africa, southern Asia and South America.
The Sand Martin is brown above, white below with a narrow brown band on the breast. The bill is black and the legs brown. Its brown back, small size and quicker, jerkier flight separate it at once from swallows and House Martins. Their twittering song is continuous when in flight, but becomes a conversational undertone after they have settled in the roost.
The Sand Martin is sociable in its nesting habits; from a dozen to many hundred pairs will nest close together, according to available space. The nests are at the end of tunnels from a few inches to three or four feet in length, bored in sand or gravel. The actual nest is a litter of straw and feathers in a chamber at the end of the burrow; it soon becomes a hotbed of parasites. Four or five white eggs are laid about the middle of May, and a second brood is usual. Their food consists of small insects, mostly gnats and other flies whose early stages are aquatic.
*Passerine: passerine is a term used for perching or songbirds.