BRUNSWICK -- Around dusk on a summer night, hundreds of small birds start to fly over the chimney behind the town's old high school.

Jackie Sartoris enjoys taking her children to the school to listen and to watch what happens next.

The chimney swifts make a gentle chippering sound as they socialize.

There's a whooshing sound as they fly.

And Sartoris says the sight is remarkable.

"You can see the birds circling and swooping together and then, all of a sudden, they gather and plummet down into the chimney. It looks like smoke in reverse motion," said Sartoris, a Brunswick town councilor.

The 60-foot-tall chimney is one of the few known roosting sites left in Maine for the chimney swift, a songbird that migrates here each May from the mountainous regions of Peru, Bolivia and Ecuador.

The issue directly affects Brunswick, which is planning to tear down its former high school so that a new elementary school can be built on the campus at McKeen and Spring streets.

The old school and its chimney are scheduled to be demolished in March 2009.

But Steve Walker, who directs Beginning With Habitat, a program run by the Maine Department of Inland Fisheries and Wildlife, said Brunswick could become the first community in New England to create an artificial habitat for its chimney swifts by building a replacement chimney on the campus of the new school.

Though removing the existing chimney may disrupt the birds temporarily, Walker is confident they would return.