Nest-Site for a Bank Swallow

Of these cavity-nesting birds, some can make their homes in a wide variety of nest sites, including the birdhouses that people build for them. Others, such as the Bank Swallow, are limited by the availability of suitable sites. A colony of these swallows may excavate a hundred or more cavities into a steep earth banks along streams or at gravel pits. Suitable sites are few, and sites that are not flooded are fewer. The lack of suitable banks may explain why the Bank Swallow nesting range barely reaches the southeastern states. The availability of mud of the right consistency and of nest supports limits the range of the Cliff Swallow. Today it is common to see many Cliff Swallows nesting under the eaves of buildings and under the concrete bridges as well as in traditional cliff sites. The need for suitable banks in which to excavate nest burrows may, in part, limit the geographical range of these Bank Swallows. Such banks must be free from flooding, soft enough to excavate, and hard enough to prevent collapsing.