A biologist with Bird Studies Canada in Sackville is warning people that the chimney swift is disappearing in New Brunswick.

Allison Manthorne, co-ordinator of Maritimes SwiftWatch, says the population of chimney swifts has declined by 95 per cent in Canada since 1968, with a close to 50 per cent range shrinkage in the Maritimes.

The birds are losing their habitat, said Manthorne, who is scheduled to speak on the issue at the New Brunswick Museum in Saint John on Monday at 7:30 p.m.

"The chimney swift historically lived in hollow trees, the kind of tree that you find in an old growth forest and our landscape has changed so much that nesting and roosting spaces don't really exist anymore," she said.

And while the birds adapted to using the chimneys of schools, churches, houses and industrial buildings, many chimneys are now being capped, steel-lined or torn down, further reducing their nesting options.

Insect decline is another problem, said Manthorne. Flying insects, such as mosquitoes, are the major food source for chimney swifts, she said.

Some big roosts

But there is hope, with a few big roosts remaining in New Brunswick, said Manthorne.

"I just had my first chimney swift report of the season in Hampton, so there is a roost in Hampton and there are also roosts in St. Anne de Madawaska, a very large one in Bathurst, one just to the east of us in Sussex, as well as Paquetville, and in Fredericton."

The large roosts can have thousands of birds that will move out and nest in neighbouring areas, said Manthorne.

Chimney swifts are small grey-brown birds with long, pointed wings and short, tapered bodies. They are often mistaken for swallows due to their shape and size.

They spend the winter months in the upper Amazon basin of South America including Peru, northwestern Brazil and northern Chile and breed in New Brunswick and Nova Scotia.