In Florida during the winter we enjoy enormous flocks of tree swallows soaring overhead and periodically dropping down to swarm over female wax myrtle bushes and eat the fruit (see photo taken at Wildflower Preserve). It is amazing that a swallow that is primarily insectivorous during the breeding season can survive the winter primarily eating dry, waxy berries. But they do so very effectively and this allows them to remain far north of other wintering birds that are unable to utilize this cold-weather food. It is interesting that tree swallows in winter gather in such large flocks and that they remain on the wing for most of the day. This is in distinct contrast to their behavior in the summer when they break into pairs and will often perch during the daytime for short periods.
We feel a strong bond with tree swallows since we enjoy their company in the summer also at our Blue Ridge mountain farm in VA. We have 107 hilly acres and open grasslands around ponds that are attractive to swallows. We have put up nest boxes to attract both tree swallows and bluebirds, who are competing for the same hole-nesting cavities. In our experience the tree swallows win these contests in open areas, except that paired boxes sometimes allow both species to nest in a more cooperative manner. In our area of VA, tree swallows only have one brood of babies, whereas bluebirds will nest repeatedly. Thus bluebirds may get to use a tree swallow box after the swallows have finished.
Male tree swallows (see photo) are a beautiful shade of metallic blue/green on their backs, due to a structural color based not on pigments but on refraction of light, with a whitish belly. Thus the angle at which you view them may change the color seen. The females and young have brownish backs. They always place some feathers in their nests, and face potential nest predation from black rat snakes (see photo) and raccoons. We have learned always to place a barrier to predators below the nest box to give the happy family the best chance to succeed.
One of the most endearing traits of tree swallows is that they thrive around homes and farms and provide a lively chorus of twittering and a rhapsody of movement as they constantly fly around to catch food and interact with one another. They drink from our ponds on the wing by skimming the surface. In the evening they take baths by crashing into the surface and splashing water on their plumage.
Tree swallows epitomize the beauty and companionship that people find in birds. So put up some next boxes and help the swallows and yourself at the same time. What a miracle of beauty and satisfaction can be found with such a small expenditure of time and money.
Bill Dunson, Englewood, FL & Galax, VA