May 14 2014
The chimney swifts came back to town in April from their winter homes in South America. In this week’s hot weather they’re zooming high above the rooftops eating insects and courting. If they’d only hold still you could see they look like cigars with wings. Here are some fun facts about them.
Chimney swifts are “songbirds” but their song is a dry chittering sound, loudest when they’re courting.
They are small. Stretch out your fingers. From the tip of your thumb to the tip of your pinky finger is the wingspan of a chimney swift. If you have big hands, your hand is wider than the bird.
Chimney swifts can’t perch on a horizontal surface. Their legs+feet are shaped like garden claws so they can only cling upright to the inside of a chimney or hollow tree.
True to their name they nest in chimneys, constructing a half-moon cup of twigs glued to the wall with their sticky saliva. To gather sticks they grab dead twigs in flight with their feet and transfer them to their bills to carry home. I have never seen a chimney swift carrying a twig. It’s something to look forward to.
Though most mating occurs at the nest, chimney swifts can mate in the air!
The female lays 4-5 eggs which both parents incubate for 19 days. Even though the chicks are born naked with closed eyes their feet are so well-developed that they can cling to an upright surface on the day after they hatch.
For such a small bird, chimney swifts live an amazingly long time, averaging about 4.6 to 5.5 years. Some have lived to be 15.
Watch them fly and they’ll inevitably look as if their wings are out of synch, one wing up and the other one down. This is an illusion caused by their rapid flapping and side-to-side turns. If you added wings to a cigar it would do the same, but not as gracefully.
(photo by Jim McCullough, Creative Commons license on Wikimedia Commons. Click on the image to see the original)