Barn Swallow
Barn swallows build their nests with mud pellets and like to reuse nests year after year. Nest building takes up a lot of energy and swallows can make more than 1,000 trips in the process. New pairs will take over unused nests so it's important to not remove old empty nests because you never know when a new pair will come.
An unmated male Barn Swallow may kill the nestlings of a nesting pair. His actions often succeed in breaking up the pair and afford him the opportunity to mate with the female.
Barn swallows are aerial insectivores meaning they catch and eat insects in the air as they fly. Most of their diet during the breeding season is flying insects. They will spend all day going back and forth, feeding their young.
Barn swallows used caves and cliffs for building of nests in the past. Now barn swallows build nests under man-made structures like barns, buildings and bridges.