Jul 29 2009
The chimney swift flocks have grown again after weeks of reduced numbers. Since the swifts arrived last spring I’ve seen the character of their flocks change four times.
First, the flocks were made up of spring migrants who chittered and ate on the way to their final destination.
The second phase was courtship in which trios flew synchronously, chittered loudly and completely followed each others’ moves. Eventually those trios became pairs as the females chose mates.
During the nesting phase the flock was cut in half because one adult of each pair was always in the chimney incubating, brooding or tending the young. The smaller flock wasn’t nearly as noisy. No need to shout, the courting is over.
And now the babies are fledging and the flock is double or triple in size and noise.
It’s fun to watch the fledglings learn to eat on the wing. They still expect their parents to feed them so they follow them closely and beg a lot but their parents don’t stop. The adults lead them through clouds of insects and the babies, whose mouths are probably open to beg, are stunned to find insects pop into their mouths. All they have to do is swallow.
Soon they are swerving and chasing insects on their own. It won’t be long before they’re as skilled as their parents and become indistinguishable as members of the flock.
(photo by Chuck Tague of a rescued chimney swift just before it fledged)