Barn Swallows: Nesting in High Places Barn Swallow nest in the rafters Barn Swallows, one of the most beloved signs of spring from Alaska and Canada to Europe and Asia, will soon reach their northernmost breeding grounds. eating lots of insects. (Even when they're not migrating, these lovely birds fly about 600 miles every day to swoop up insects!) Swallows already on their breeding grounds are also busy building nests on many barns, garages, and homes. Barn Swallows make a cup nest that they stick on the walls of a barn or other strucure. The birds nest individually, though nests can be fairly close to each other. On the outside each nest looks deep, but it's mostly mud through and through. The actual nest is a shallow cup, but it holds the babies just fine. Two different swallow species—Barn Swallows and Cliff Swallows—build mud nests on buildings and bridges. How can you tell them apart? See: Mud Swallows: Which is Which? Try This! Journaling Question Barn Swallows nest almost entirely on buildings, bridges, culverts, and other human constructions. This makes sense in a world with so many humans. But what about before people made buildings and bridges? Where did they nest then? And how do we know what swallows were doing before ornithologists were keeping records? Find out in Swallows Then and Now. Big waves of swallows rush through in spring a week or two before big waves of warblers, even though both groups eat insects. But swallows eat flying insects, while warblers usually eat crawling insects. What might account for the timing difference between the waves of swallows and waves of warblers? Copyright 2004 Journey North. All Rights Reserved. Please send all questions, comments, and suggestions to our feedback form