Tree Swallow (Tachycineta bicolor)
Overview: Male Tree Swallows are an iridescent steely blue-green above with a white belly and a thin black mask around the eye. Flight feathers are blackish and tail is distinctly notched. Females are slightly duller than males. Juveniles are dusky gray-brown above, with a dusky smudge across the breast.
Field marks: A glossy blue-green swallow with a clean white belly. Swallows have slender bodies with long, pointed wings.
Size: 5¾ in.
Sounds: Song is a high-pitched, liquid twitter, composed of three sounds—a chirp, a whine, and a gurgle—which they mix and match in a variety of patterns. Both males and females sing. Call is a rich cheet or chi-veet. Also, aggressive chatters, shrieking alarm calls, harsh distress calls, and amorous ticking sounds (listen to this bird here).
Behavior: Acrobatic aerialists, Tree Swallows spend most of their time in the air. They glide in circles, ending with quick flaps and a short climb.They tend to glide more than any other swallow species. They are playful and highly social birds that form large migratory and wintering flocks; pairs often nest close together. Commonly swarm and dive-bomb predators while giving alarm calls.
Habitat: Open country or woods near water; marshes, meadows, streams, lakes, wires; fall premigratory flocks roost in reeds; nests in holes in trees, birdhouses
Diet: Flying insects; occasionally plant foods; during the breeding season, high calcium items such as fish bones, crayfish exoskeletons, clamshells, and eggshells of gulls or loons
How to attract: Place nest boxes in appropriate habitats (find plans for a nest box, along with information on where to hang it here); plant native bayberry bushes
Fun Facts
Tree Swallows bathe by flying low over the water and skimming their bodies against the surface, then rising quickly while shaking off droplets.
Tree Swallows line their nests with feathers, and they seem to display or even play with these feathers during the early nesting season. A bird flies above the nest with a feather held in its bill; sometimes this leads to chases, and sometimes the bird drops the feather, causing an aerial free-for-all to see who retrieves it.
The Tree Swallow—which is most often seen in open, treeless areas—gets its name from its habit of nesting in tree cavities. They also take readily to nest boxes.
Migrating and wintering Tree Swallows can form enormous flocks numbering in the hundreds of thousands. They gather about an hour before sunset and form a dense cloud above a roost site (such as a cattail marsh or grove of small trees), swirling around like a living tornado. With each pass, more birds drop down until they are all settled on the roost.
Facts provided by the Cornell Lab of Ornithology.
Information compiled from multiple sources.