Earlier this year, the bird was assessed with the designation of ‘Threatened’ by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC). COSEWIC is the scientific body that advises the federal government on the status of species at risk.
Since 1967, the number of chimney swifts in Canada has plummeted by 95 per cent. Chimney swifts are sooty-coloured, swallow-like birds that nest and roost mainly in old, large-diameter, brick-lined chimneys. From late April to early October, sunrise to sunset, chimney swifts fly high in the sky, each eating up to a thousand insects a day.
The main reasons behind the dramatic drop in swift numbers are believed to be a general decline in insect populations and a shortage of suitable nesting and roosting sites. At night, the birds cling by their toenails to the vertical brick interior. Chimney swifts also build nests inside chimneys, using their glue-like saliva to attach twigs together and to the bricks.
With the growth of gas furnaces and chimney conversions to include metal linings, the stock of available chimneys suitable for use by swifts has been steadily diminishing since the 1960s.
“In presenting this certificate, we are recognizing the importance of six of Western’s chimneys for breeding chimney swifts. By raising awareness of the needs of this threatened species, we hope Western will continue to maintain these chimneys in such a way that they will provide essential nesting habitat for swifts in years to come,” says Winifred Wake, SwiftWatch’s Volunteer Coordinator.
Questions and Answers on Chimney Swifts from McIlwraith Field Naturalists
Where did swifts nest before there were chimneys?
In pre-settlement times, chimney swifts nested and roosted in large-diameter hollow trees, a common feature in North America’s original forests. Today, such trees are rare, the result of several centuries of land clearance and current management practices within woodlands.
Why have I never noticed swifts before?
Because of the design of their feet, swifts are unable to perch on trees or wires or to land on the ground, where they could be easily noticed. During daylight hours, swifts tend to feed relatively high in the air column. While in flight, they often emit soft, chattering calls, which can alert a person on the ground to their presence.
Where is the best place to see swifts?
From mid-August to early October, chimney swifts gather at dusk to dive into selected large, old chimneys to roost communally for the night. Supplemented by migrants arriving from the north, numbers may reach hundreds or even thousands. The sight of so many birds swirling and chattering overhead, then diving headlong into a chimney is truly spectacular. Preferred roost sites may change from week to week. The Nature Line (519-457-4593) of the McIlwraith Field Naturalists (updated on Thursdays) usually carries current information during the fall swift migration season.
Where do swifts go in the winter?
Chimney swifts spend the winter in the upper Amazon basin, mainly in eastern Peru and western Brazil.
Do swifts ever use house chimneys?
Large communal roosts occupied by swifts during migration are almost invariably located in the big brick or concrete chimneys of commercial or institutional buildings. Although the SwiftWatch program has not, to date, directed its attention to private homes, swifts will nest in the smaller-diameter brick chimneys of houses. Most house chimneys used by swifts are found on pre-1960s buildings. A minimum interior diameter of 25 to 30 cm is required (indicated by a horizontal course of bricks that is a minimum of 2½ bricks wide per side, as seen from the outside). The chimney cannot be capped or covered with wire mesh or any other device that would prevent access by the swifts. In addition, the chimney shaft cannot be lined with metal.
How many swifts nest in a chimney?
Only one pair of swifts nests in one chimney, though sometimes up to half a dozen additional swifts also roost in the chimney at night during the nesting season.
How can I keep my chimney open for the swifts and yet keep out raccoons and squirrels?
A sheath of metal about 60 cm wide placed around the chimney on the outside, just below the top, will keep out unwanted animals.
I plan to install a gas furnace and the installer says he needs to line my chimney with metal. Is there a way I can still accommodate chimney swifts?
A gas furnace does not need to be vented up the existing chimney. Vent your furnace elsewhere and leave the chimney unlined for the swifts.
What happens if I want to use my chimney?
Swifts are in Canada from late April to early October, a period when chimneys are generally not needed for heating purposes.
Won’t swifts in my chimney cause problems with poop or create a fire hazard with their nests?
Owners of chimneys used by swifts generally report little or no problem with poop. Nests are so small and constructed of such fine twigs that they pose no fire hazard. As a safety measure, it is always wise to have chimneys cleaned regularly. If swifts are suspected to be nesting in a chimney, avoid having it cleaned between mid-May and mid-August.
Why have the numbers of chimneys suitable for swifts been decreasing?
At time goes on, old buildings and their chimneys are torn down. In the past half century, few chimneys have been built that meet the needs of swifts. In addition, many existing chimneys have been capped, fitted with an animal guard or lined with metal to accommodate a furnace conversion.