Chimney swifts make selves at home

For several weeks now, we’ve been hosting a visiting family at our home in Decatur. They have been hardly any trouble, and we have enjoyed having them. But lately they’ve become a little noisy, and we’ll be pleased when they finally depart for their winter homes.

I’m talking about a family of chimney swifts that moved into our brick chimney earlier this summer. We first heard them tweeting and scratching around in early July. I suspected then that they were building a nest, and I was right.

Though I can’t see the nest, I know what it probably looks like from previous inspections of swift nests. A pair of chimney swifts builds a half-saucer shape nest of loosely woven dead twigs and cements it together – and to the chimney wall – with a glue-like saliva.

A few weeks ago, we began hearing the distinct chittering of baby swifts from our chimney – begging for food from their parents. At first, the chittering was little more than background noise. In the past week or so, though, it has gotten louder and distracting as we sit in our den to watch TV or read.

To make sure none of the babies tumble down the chimney and flit out into the den, we’ve made sure the fireplace damper is closed. As further precaution, my wife has draped a blanket over the fireplace.

We know, though, that soon the birds will leave us in peace. They will head to winter grounds in the upper Amazon basin of Peru and other areas of South America. “Most are gone by mid-October and all by early November,” says ornithologist Todd Schneider of Georgia’s Wildlife Resources Division.

Sometimes migrating chimney swifts gather in large, swirling “swarms” to roost in large chimneys. One such swarm was spied at Grady High School in Midtown Atlanta the other day.

Meanwhile, from my front porch it’s a pleasure to watch the speedy adult swifts, with wing spans up to 12 inches, dart about in the evening sky, zapping up airborne insects. Their sleek shape has earned them the nickname “flying cigar.“ The 5-inch-long birds, in fact, do almost everything on the wing — eating, drinking, breaking off twigs for their nests and even copulating in flight. They stop only to nest and roost. Their small, weak legs prevent them from perching like other birds, but they have strong feet and stiff tail bristles that allow them to cling to rough, vertical surfaces.

The swifts once depended on tree hollows for nesting and roosting, but they adapted to brick chimneys (metal chimneys are unsuitable) and other human structures because of the loss of natural sites through deforestration.

In the sky

The moon will be new on Thursday. Mercury is low in the west just after sunset, says David Dundee, astronomer with the Northwest Georgia Science Museum. Venus, shining brightly, rises three hours before the sun. Mars rises out of the east almost four hours before sunrise. Jupiter rises out of the east at sunset and sets in the west at about sunrise. Jupiter will appear close to the moon Friday night. Saturn is low in the west at sunset.