Birds nest in trees, nest boxes, bushes, or even on the ground. Yet, chimney swifts don’t follow the norm. As the name implies, these birds seek out chimneys for nesting, which is a habit only a few bird species share. So, why does the chimney swift have such peculiar nesting habits?
What is a Chimney Swift?
These swifts are small birds with gray-brown coloring. They have long, curved wings and a bill that’s so small it barely sticks out from their face. They fly quickly and erratically, and they never perch on branches.
Chimney swifts live near human-made structures across eastern North America and northern South America. They’re typically found across the United States during the breeding season, and then they migrate down to South America for the nonbreeding season.
Their calls include fast, high-pitched notes, lasting about three seconds long. They often fly in crowded groups, causing them to make buzzing insect-like sounds when they all chirp at the same time. If an intruder approaches their nest, they may snap their wings together to make a loud sound to scare them off.
Are Chimney Swifts Endangered?
This bird species isn’t endangered, but it’s currently at risk. Chimney swifts are vulnerable, meaning they’re on a watch list because of their declining population. The decline could be because of limited nesting spots, due to chimney designs not being as suitable for birds to get inside.
Chimney Swift Nesting Habits
These birds live up to their name because their most common nesting spots are chimneys. They have long claws that prevent them from perching on branches like other birds. Instead, when they stop flying, they need to cling to vertical walls, which is why they’re drawn to chimneys. They fly almost constantly when they’re not roosting or nesting.
When chimneys aren’t available, these birds turn to other human-made structures of a similar shape, such as vents, barns, and silos. They may also nest in natural structures, such as caves and hollow trees.
Unfortunately, many modern chimney designs aren’t suitable for the chimney swift. They’re often covered or too narrow for birds to nest in. This may be a factor for the species’ declining population.
Why Do These Birds Nest in Chimneys?
Since these birds need secure vertical perches, chimneys are a perfect design. They can use their long claws to cling to chimney walls. With walls on all sides, the space is dark and safe for the birds to build nests and lay eggs.
To build nests, chimney swifts release sticky saliva from under their tongues to attach the nest to the chimney’s wall. During the breeding season, usually only one mating pair lives in a chimney, but a nonbreeding adult may help care for the young. During nonbreeding seasons, lots of birds may roost in the same chimney.
Is it Okay for These Birds to Nest in Your Chimney?
In most cases, these nesting behaviors are harmless. The birds might leave a mess behind, but they won’t damage the chimney’s materials. So, if you occasionally hear chirping and rustling in your chimney, there’s no need to worry. The babies become the loudest when they first hatch and want food. Once they’re old enough to get their own food, they’ll be quieter.
Chimney swifts eat thousands of flying insects a day, including flies, termites, mosquitoes, gnats, and wasps. Having them in your chimney can reduce the number of pesky critters flying around your property.
The only downside to having these birds in your chimney is that you cannot have a fire in your fireplace while they’re there. Luckily, they usually nest in the spring and summer, so it’ll be too warm for a fire anyway.
About a month after hatching, the baby birds can fly around on their own, no longer needing the nest as much. By October, the whole family will fly south for the winter.
What to Do if the Nest Falls
In rare cases, the nest or baby birds could fall. If you notice a nest or young bird outside of the nesting area, return them to their parents if possible. The easiest way to do this is to place the nest and baby birds on the chimney’s smoke shelf. If there isn’t a way to return the birds to the chimney, contact a wildlife rehabilitation center.
Can You Remove a Chimney Swift Nest from Your Chimney?
Once one of these birds builds a nest in your chimney, you cannot remove them. It’s illegal to do so because they’re a protected species. So, if you hear them nesting, you’ll have to wait until they leave before cleaning the chimney.
Removing them is also bad because the birds might not have many other nesting options nearby. Suitable chimneys are scarce in modern houses, and they can’t nest on branches and in regular nest boxes like other birds. You can deter them by putting a cap on your chimney, but if you do that, consider offering other places for them to nest.
Can You Offer a Nesting Box to Chimney Swifts?
Even though these birds don’t harm chimneys, some people might prefer to keep them off their house. Rather than just trying to deter them, offer other places for them to nest. Many homes don’t have chimneys suitable for nesting anymore, so providing special nesting spots for this species could be beneficial to the population.
Instead of setting up a traditional nesting box, you’ll need to provide a nesting tower for chimney swifts. Nesting towers are free-standing structures that are about 12 feet tall, resembling a chimney. Since they’re large and can be pricey, consider working with nature centers, schools, or other groups to build one.
Once you have the funds and a location in mind, chimney swift towers are fairly easy to put together. You can put the sections together before you place it somewhere. With plenty of nesting towers, these birds will have more choices for where to nest, making them less likely to choose your chimney.
