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Chimney Swift (Chaetura pelagica)

prepared on behalf of Nature London by W. Wake. August 17, 2021

The delightful little Chimney Swift belongs to a group of birds known as aerial insectivores. This means it dines only on insects caught in flight. Swifts fly high on stiff, rapidly beating wings, twittering softly as they zoom about above treetops and buildings. They are often heard before their black, crescent-shaped profile is seen.


Listen to Chimney Swifts by clicking below. Source:


Swifts are most readily found in towns and cities. They first appear in London in late April and are gone by early October. Swifts construct tiny twig-and-saliva nests inside old unlined, open-topped brick chimneys (one nest per chimney). From nest building to fledging takes about 10 weeks. When not actively breeding, swifts may gather by the hundreds to spend nights roosting together inside large, unused chimneys. Chimney Swifts winter in South America.

The unobtrusive Chimney Swift makes an ideal houseguest. Londoners may have swifts nesting or roosting in their home or business chimneys yet be unaware of their presence.


Learn how to determine if swifts are using your chimney and how to be the best swift landlord ever!


If swifts accidentally come down your chimney into your living room, close doors, draw drapes and turn off lights. Then open doors and windows to create a route that will help lead swifts towards the brightness that is the world outside. To prevent such problems, be sure to keep the fireplace damper firmly closed during swift season. If swifts are nesting in the chimney, youngsters may make food-begging calls for a few weeks. Enjoy these exuberant baby noises and take pride in providing a safe nesting place for a species at risk.

Click here to read more about London’s swifts


Since the 1960s, swift numbers in Canada have plummeted by more than 90%. In 2009, the Chimney Swift was designated as Threatened. Here are a few of the reasons for the swift’s troubles.

  • Food supply. Due to pesticide use, the expanding urban footprint, industrial agriculture, loss of wetlands and woodlands, and other factors, insects in the air are less abundant than they once were.

  • Nesting and roosting habitat. Old hollow trees, wooden barns and suitable chimneys are steadily disappearing. Purpose-built swift towers are very expensive and rarely used by swifts in Canada.

  • Extreme weather. Torrential rains and cold snaps can wash out nests and disrupt the food supply.


Read more about why swifts are declining in London and across Ontario.


Video recording from inside a chimney containing 293 swifts. Source

London’s swifts are fascinating to watch as they perform aerial acrobatics across the sky. In older well-treed neighbourhoods, and in old commercial and industrial areas, listen for swifts, then look up and enjoy the show. From May to July, the best place to see swifts around nest chimneys is at First-St. Andrew’s Church, 350 Queens Ave (map) (there’s even a viewing bench and an interpretive sign).


At sunset, flocks of non-breeding swifts make spectacular dives into chimneys to spend the night.

Check out more videos of swifts entering roosts.

It is always hard to predict where the biggest swift roost numbers will be.

Find where to see Chimney Swifts in London, Ontario.

1400 swifts enter the chimney at Labatt’s Brewery in London, ON. Recorded by Brendon Samuels on September 12, 2018 between 7:40 and 8:10 pm.

Help make London as swift friendly as possible:

  • If you own a chimney used by swifts, maintain it in a way that keeps it available for swifts.

  • Advocate for the preservation of older, heritage buildings whose chimneys are used by swifts.

  • Support the protection of natural habitats, which produce insects that waft upward for swifts to eat.

  • Grow native plants in your yard to help support caterpillars and other insect stages that, as adults, may travel skyward to become swift food; encourage friends and neighbours to do the same.

  • Avoid use of pesticides and reduce your ecological footprint as much as possible.

  • Join Nature London’s swift monitoring crew and help track migrating swifts and nesting-season activity.


Learn more about how to help London's Chimney Swifts.


Our city is already known as a good place for swifts. Working together, let’s make it even better.

Nature London has been a leader in swift conservation, advocacy and education since 2003. The club operates one of the most comprehensive swift outreach and monitoring programs in Ontario.

This video includes footage and information about behaviours of the Chimney Swift while inside a chimney .

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