A Chimney Swift Guide for Homeowners
Chimney Swifts are small, fast-flying, sooty-gray birds that spend the daylight hours catching insects in flight. They annually migrate from the Amazon up to eastern North America, where they breed in the spring months. They are protected by the Migratory Bird Treaty Act. In the last 50 years, Chimney Swift populations have declined by over 50%. This is due, in large part, to the lack of suitable nesting habitat.
Historically, these swifts nested and roosted in old growth trees, but now almost exclusively nest in chimneys. As more chimneys are capped or lined with metal flues, swifts are losing critical nesting structures. This problem poses a unique opportunity for homeowners to learn how to steward their chimneys for swifts without any need to sacrifice normal chimney use.
If Swifts are Nesting in your Chimney
Congratulations! This is exciting because it means that your chimney, your chimney flue, and your chimney cap may all be suitable for allowing these at-risk birds to safely nest in your chimney.
Remember, these are at-risk birds that cannot nest anywhere else, so your chimney is critical for helping restore their numbers. They do not cause any damage, make a mess, or pose a fire or health hazard.
Enjoy watching them enter and exit your chimney throughout the day as they tend to their eggs and eventually nestlings.
Best Practices:
- During the nesting season, do not light a fire and do not disturb the nest.
- Make sure your damper is closed for the nesting season, which will prevent the possibility of a young swift falling out of the nest and into your hearth or stove. If the damper is shut, it will remediate the fall, and the young swift will crawl back up and into the nest.
Unsafe Swift Chimney
If chimney has a metal flue liner, which is not conducive for nesting swifts, the chimney should be capped.
Swift-Friendly Chimney
If chimney has a terracotta or other type of textured flue, which can be conducive for nesting swifts, either leave uncapped or add a Chimney Swift-friendly cap.
Use & Maintenance Timeline for a Chimney Shared with Swifts
Sharing a chimney with Chimney Swifts is easy because they only need to use the chimney for nesting during the warmer spring and summer months. It is good practice to have your chimney cleaned by professionals annually in the autumn months before the weather cools.
Photo at top of page by Katy Perrault