Chimney Swift

(Chaetura pelagica)

Status: Threatened (ESA & SARA, 2009)

Table of Contents:

Species Identification
Diet
Habitat and Range
Biology and Behaviour
Similar Species
Threats/Reasons for Being Endangered
Conservation and Recovery Strategies
How You Can Help

Photo by: Kent McFarland https://flic.kr/p/9JTVqD

Species Identification:

This small, cigar-shaped bird has a long body and long pointed wings, with a body length of only about 12-14 cm. It has a short tail and a quick, jerky flight pattern that is easy for identification. Both sexes look similar since they both have feathers that are dark brown with a lighter throat.

Diet:

The Chimney Swift is an aerial insectivore that spends the majority of its day flying and hunting small insects. Their diet consists of beetles, bugs, caddisflies, mayflies, crane flies, wasps, ants, and bees. They spend most of their life in the air, even diving down over water bodies to drink while in flight. They forage at a height from about 20 to 150 m, and generally prefer areas close to water. Historically Chimney Swifts were mainly found in old growth forests, but today they have adapted to urbanization, nesting and foraging in cities.

Map taken from: https://www.canada.ca/en/environment-climate-change/services/species-risk-public-registry/cosewic-assessments-status-reports/chimney-swift-2018.html

Habitat and Range:

About one quarter of Chimney Swifts breed in Canada, which includes eastern Saskatchewan, and southern parts of Manitoba, Ontario, and Quebec, as well as across most of the Atlantic Provinces. They also breed within the eastern United States, all the way down to Texas and Florida. The majority of Canadian Chimney Swifts breed in Ontario (an estimated 7,500 out of 11,800 individuals). Populations are concentrated in the southwest region of the Province around the Golden Horseshoe, with scattered populations across the southern Canadian Shield in The Land Between.

The Chimney Swift is not associated with one type of habitat, and will forage over cities and a range of natural landscapes. They are most often found near human habitation since they have adapted to nesting in human structures. In some rural areas, Chimney Swifts still roost in tree cavities and rock crevices as they did before European colonization of North America. They require a vertical cavity with a stable interior to build their nest. They will typically nest in cavities of large trees, but after the widespread removal of mature forests in North America, Chimney Swifts started nesting in chimneys, silos, barns, and abandoned buildings.

The Chimney Swift migrates to South America each fall, congregating in the southern United States before crossing the Gulf of Mexico. Winter habitats are not very well known, but they will roost in tree cavities and chimneys of tropical forests and towns. They overwinter throughout northwestern South America.

Biology and Behaviour:

Adult swifts return to their Canadian breeding grounds in April or May. Most will keep their same partner long-term and return to the same nesting site in successive years. The pair builds their nest a few meters down the chimney using their sticky saliva to stick twigs to the vertical surface. Nests from previous years may be patched up and reused if they are in good condition. In Ontario, 2-5 eggs are laid between mid-May 24 and early August and incubated for about 20 days. Both parents look after their nestlings, and the first flight occurs about 30 days after hatching. The oldest recorded Chimney Swift was 14 years old, but their average age is 4.6 years.

The Eastern Rat Snake is known to prey on Chimney Swift nests. Adults may be preyed on by several raptor species, often as they enter or exit a chimney. Swifts can be seen flocking in large numbers for protection, but nest solitarily.

Photo by: Ryan Mandelbaum https://flic.kr/p/2gs63DU

Similar Species:

The Chimney Swift may be confused with several swallow species since they have similar habitats and a similar body shape. Swallows can be distinguished by their much smoother flight pattern, shorter wings, and they usually have a notched tail.

Threats/ Reasons for being at Risk:

These birds are part of the aerial insectivore group that have seen steep population declines since the 1970s. The Canadian population of Chimney Swifts has declined by 95% since 1968.

1. Declining insect populations: The main factor affecting many aerial insectivores is a decrease in global insect populations. The causes of these declines are complex, but likely is attributable to a combination of loss of specific insect habitat (e.g. draining wetlands), and use of pesticides for agriculture, forestry, and mosquito control. This happens in both their breeding and wintering grounds.

2. Residential and commercial development: Because they have become dependent on human structures, Chimney Swifts are now susceptible to chimney modifications or destruction. Development projects that drain or fill wetlands also impact insect availability, and are therefore detrimental to Chimney Swifts.

3. Logging and wood harvesting: Loss of mature forest and removal of dead wood limits natural nest sites. Short rotation periods in forestry management do not allow for big mature trees to develop, leaving Chimney Swifts to resort to urban nesting.

4. Cumulative impacts: There are a number of other contributing threats, although their relative importance is difficult to assess. For instance, there may be direct effects of pesticides and pollutants like heavy metals. Climate change and increasing severe weather events may also pose a threat to these long-distance migrants, making their trip more hazardous.

Photo by: Paul Hurtado https://flic.kr/p/pq9V9e

Conservation and recovery strategies:

Some effort has been made to try and quantify the number of stone chimneys that have been capped or otherwise made unavailable to Chimney Swifts. Surveys found that 14-29% of surveyed chimneys were no longer usable.

Best Management Practices (BMPs) for forest managers are available. For instance, Birds Canada recommends retaining large trees and harvesting outside of the breeding period.

The Provincial government’s Tree Marking Guide requires forest managers to leave the tallest trees and trees with Pileated Woodpecker cavities. These trees are beneficial to Chimney Swifts and other cavity nesters.

How can you help?

If you need to do maintenance work on your chimney, including chimney cleaning, wait until after breeding season (May to September)
Report any sightings to Birds Canada’s Swiftwatch program (link). You can also volunteer with them to find nest sites and help with stewardship activities
Farmers or landowners with Chimney Swift nests on their property may be eligible for provincial stewardship programs
Encourage insect populations by protecting all wetland areas and/ or installing an insect feeder on your property (e.g. the Humm-Bug Hummingbird feeder)