Chimney swifts are small, dark colored birds that nest and roost in chimneys and other vertical structures. Once abundant across North America, chimney swift populations have seen significant declines in recent decades, leading some to wonder – are chimney swifts rare?
Quick Answer: Are Chimney Swifts Rare?
Yes, chimney swifts are now considered a rare bird species. According to the International Union for Conservation of Nature (IUCN), chimney swifts are listed as Near Threatened and their populations have decreased by over 30% since the 1960s. The major causes of the chimney swift decline are loss of nesting and roosting habitat. As old hollow trees and chimneys are removed across their range, chimney swifts have fewer and fewer places to breed and rest.
Chimney Swift Population Declines
Chimney swifts were once very common birds across eastern North America. Their loud chattering flocks were a familiar sight as they swept across the sky at dusk. Chimney swifts got their name because in the late 1800s and early 1900s, they adapted from nesting in large hollow trees to using chimneys for roosting and nesting sites. The inner brick sides of chimneys mimicked the hollow trees swifts relied on.
During the 20th century, as more homes were built with chimneys, chimney swift populations thrived and expanded their breeding range northward across Canada. However, since the 1960s, a number of long-term surveys have documented severe declines in chimney swift populations:
- According to the North American Breeding Bird Survey (BBS), chimney swift populations declined by 1.5% per year from 1966 to 2015, resulting in a cumulative decline of 75% over that period.
- Chimney Swift population monitoring in Canada found the birds declined by 95% between 1968 and 2005.
- Counts at migratory roosts sites found 75-80% declines between the 1980s and early 2000s.
- Radar studies estimate a 2.9% annual decline in chimney swift migrations between 1989 and 2016.
While chimney swifts are still found across eastern North America, their populations are now a fraction of what they once were. The species is considered endangered, threatened, or a species of special concern in many states and provinces where it was once abundant.
Why Are Chimney Swifts Declining?
The main cause of chimney swifts’ declines is habitat loss. Chimney swifts nest exclusively in cavities – in hollow trees or in chimneys. They also roost communally in unused chimneys and other structures during migration and in winter. As old trees are removed and chimneys capped or lined with metal for efficiency, chimney swifts are left with fewer and fewer suitable nesting sites and roosts. Other contributing factors may include:
- Pesticides reducing insect prey populations
- Climate change disrupting migration and nesting periods
- Predation by expanding raptor, owl, and squirrel populations
Regardless of the causes, it is clear chimney swift populations have decreased dramatically. Without more conservation action, the unique chimney swift may continue to decline towards extinction.
Chimney Swift Nesting Biology
Chimney swifts are well-adapted to nesting and roosting in vertical cavities. Here is an overview of their unique nesting biology:
- Nest Sites: Chimney swifts build bracket-shaped nests on vertical walls inside chimneys, hollow trees, wells, silos, and other structures. Nests are made of twigs glued together with saliva.
- Breeding: Chimney swifts form pairs in late summer that reunite the following spring at nest sites. Courtship displays involve grouped flying chases.
- Egg Laying: Females lay 3-5 white eggs from late April to early July. The eggs are tended constantly and hatch after 19 days.
- Chicks: Chimney swift chicks (called nestlings) are altricial – born naked and helpless. Parents feed insect prey to chicks which fledge after about a month.
- Roosting: Chimney swifts roost communally in chimneys and other structures at night and during migration. Hundreds may roost together through winter.
This unique nesting behavior makes chimney swifts very dependent on suitable vertical cavities. With fewer hollow trees and accessible chimneys, their breeding habitat continues to shrink.
Where Chimney Swifts Live
Chimney swifts are found across eastern North America during the breeding season. Their breeding range extends:
- As far north as southeastern Canada (Ontario, Quebec, New Brunswick, Nova Scotia).
- South to the Gulf Coast states from Texas to Florida.
- West to the Great Plains from North Dakota south to Oklahoma.
The core of their breeding population is centered around the Upper Midwest and Northeast United States. During winter, chimney swifts migrate to roost sites in the Amazon Basin region of Peru and Brazil in South America.
Chimney Swift Range Map
Here is a map showing the chimney swift’s current and historical breeding range:
Their breeding range has contracted in recent decades, especially in the northwest and Canadian parts of their range. Few chimney swifts now nest in western Ontario, Manitoba, or Minnesota for example. Protecting remaining populations throughout their core range is crucial for the species’ survival.
How to Conserve Chimney Swifts
Because chimney swifts rely so heavily on chimneys and other human-made structures, they can thrive in close proximity to humans if provided with suitable habitat. Some ways homeowners and landowners can help conserve chimney swifts include:
- Preserving old unused chimneys as swift nesting and roosting habitat
- Installing specialty swift towers or nest boxes to provide nest sites
- Capping chimneys with special caps that allow swifts to enter and exit
- Avoiding chimney cleaning and maintenance during nesting season
- Leaving dead and dying trees standing when possible
- Educating others about swift conservation
A range of swift conservation and monitoring programs have also been established across their range. These include swift nights out where people observe chimneys at dusk for migrating flocks, chimney swift chimney surveys to monitor breeding sites, and projects to install swift-friendly chimney caps and nest boxes. With active conservation efforts, hopefully stable chimney swift populations can persist.
Fun Facts About Chimney Swifts
Beyond being rare and unique birds, here are some fun facts about the amazing chimney swift:
- Chimney swifts spend almost their entire lives airborne. They even sleep while flying by entering a state of deep torpor!
- The tiny feet of chimney swifts are specially adapted to grip vertical surfaces but they can’t perch horizontally.
- Chimney swifts beat their wings up to 200 times per second and can reach speeds of up to 60 mph in flight.
- They bathe by flying through rain and scooping up droplets of water.
- Chimney swifts migrate immense distances, covering over 6,000 miles twice a year between North America and South America.
Conclusion
Chimney swifts are fascinating birds that were once common but are now rare and in need of conservation. As their name implies, they rely heavily on chimneys and similar human structures for breeding habitat. With population declines of 75-95% primarily due to habitat loss, chimney swifts are considered a threatened species. However, there are ways we can help – by protecting existing chimney habitat, installing new nest structures, and educating others. With active stewardship, the unique chimney swift still has hope for long-term survival across North America.
