photo One of the easiest ways to observe tree swallows is to build a birdhouse in your yard.

Of the seven species of swallows in the United States and Canada, the one that is the most common here in Oregon is the tree swallow. These small cavity-nesting birds usually nest in woodpecker holes in dead snags, but as the starlings have taken over these snags, the tree swallows have learned to nest along the eaves of buildings and are quick to utilize birdhouses.

They are very efficient nesters and return to the exact area where they were born. Once they take possession of their nest, they will chase away larger birds such as crows or magpies. They nest from Alaska to Southern California. They lay from four to seven eggs and feed their young solely on insects that they catch on the fly.

Our tree swallows winter in Southern California, Arizona and New Mexico.

When the breeding season is over, all of the swallows tend to gather together in huge flocks. They can be seen on telephone wires, too numerous to count. Once the southward migration occurs, they fly only in the daytime and their numbers increase as they fly leisurely to their wintering grounds. We won’t see another tree swallow until about the middle of April at this latitude.

When you consider the large number of swallows and the huge amount of insects they consume, I can’t think of any insect-repellent that can equal the benefits of these acrobatic swallows. Their wide beaks are lined with sticky stuff that makes it impossible for any flying insect to escape. Sometimes they skim along on a pond catching mosquitoes and other times they will be flying so high we can barely see them.

If you really want to watch them up close, put up a birdhouse in your back yard.