This week’s Bird of the Week, compliments of the Weminuche Audubon Society and Audubon Rockies, is the tree swallow.
The tree swallow is one of the summer birds which arrives early in our region. They winter farther north and return to nesting areas earlier than other swallow species.
Although like other swallows they primarily feed on insects caught on the wing, they will also eat seeds and berries. This allows them to survive unpredictable cold snaps in spring when insects are unavailable.
Tree swallows are small birds with tiny bills; long, pointed wings; and a short squared or slightly notched tail. Adult males are colored blue with green hues above and white below. Females are duller with more brown tones above.
These birds are most often seen flying in open, treeless areas near water. The “tree” in their name was derived from their reliance on tree cavities, often old woodpecker holes, for nesting. Maybe not the blue-colored bird that people are hoping to attract, they will also readily nest in bluebird houses which have the perfect size hole.
Showing a preference for white, tree swallows line their nests with the feathers of other species. Early in the nesting season, they engage in play by flying with a feather in the bill, dropping it and swooping down to catch it in midair. These birds are quite social and will often nest close to each other.
A study summarized in Sciencedaily.com has reported that with our warming climate, about one-third of the bird species observed nesting in the Chicago area are reproducing on average a month earlier than they were 100 years ago. This trend has been observed in tree swallow populations.
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