14 May 2014

Chimney swifts (Chaetura pelagica) return 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.  In flight they look like cigars with wings.  Here are some fun facts about them.

• Chimney swifts are small. Stretch out your fingers as wide as you can. The wingspan of a chimney swift is the distance from the tip of your thumb to the tip of your pinky finger. If you have big hands, your hand is wider than the bird.

• Outside of the swift family (Apodidae) hummingbirds (Trochilidae) are their closest relatives.

• Chimney swifts “sing” a dry chittering song that is loudest when they’re courting.

• Though most mating occurs at the nest chimney swifts can mate in flight!

• Swifts cannot perch horizontally. Their legs+feet are shaped like garden claws so they can only cling upright to the inside of a chimney or hollow tree.

• They nest in chimneys, constructing a half-moon cup of dead twigs glued with their sticky saliva.

• To build a nest they grab dead twigs with their feet as they fly past trees, then transfer them to their bills to carry home.  I have never seen a swift gathering or carrying twigs.  It’s something to look forward to.

• The female lays 4-5 eggs which both parents incubate for 19 days.  Because they delay incubation until the next-to-last egg, most of the eggs hatch on the same day. The young fledge at 28-30 days.

• Sometimes one or two non-mated swifts will help a pair incubate, brood and feed their young.

• Chimney swifts can live an amazingly long time, averaging 4.6 to 5.5 years.  Some have lived to be 15.

• In flight they sometimes look as if their wings are out of synch, one wing up and the other down. This illusion is caused by their very rapid side-to-side turns. 

(photo by Jim McCullough, Creative Commons license on Wikimedia Commons. Click on the image to see the original)