Sometimes a bird’s name can tell you a lot about it. Chimney swifts are fast flyers, and they often build nests in chimneys. This makes them city-dwelling birds today, but that wasn’t always the case.

In the past, much of Canada was covered with old, mature forests. Those forests contained standing dead trees, called snags. Chimney swifts chose snags with hollow trunks and an opening at the top. Sometimes they chose caves, too. In these safe, dark, semi-enclosed spaces they would build their nests and raise their young.

Outside the nest, the swifts use their flying skills to catch and eat their meals in midair. They are insectivores, which means insect-eaters. Their diet includes wasps, mayflies and beetles. This makes them a natural form of pest control in the ecosystem. They keep insect populations at stable, healthy levels. That’s a bonus for any nearby farmers!

When Canada’s forests were logged, the snags were cut down and the caves disturbed. Fortunately, the cities that emerged in their place had a perfect feature: lots of hollow chimneys with an opening at the top. The birds adapted to their new homes.

Today, chimney swifts face a new set of challenges. New homes are not built with chimneys, and many old ones are being torn down. At the same time, insect populations are declining, so there’s less food for swifts. One reason for this is the growing use of pesticides.

Some things have gotten better. Foresters know how important snags are now, and they’re required to leave many standing. But to help chimney swifts recover, we’ll have to give them more than habitat. We’ll have to change our pesticide habits so that insect populations stay in balance, giving swifts enough to eat.