heron at the dam

The last time I went walking in North Park was the end of April. And back then, spring was just edging into the hillsides and shores around the man-made lake. Two months later and the park has pulled its green canopy over the roads, the trails and steams; it has dressed itself in thorny briar, new cattails, red berries, pink roses and hanging vines. (i began hiking north park in mid november, so I never saw it green)

Two things surprised me last night; Pine Creek, along the southern bend of Lake Shore Drive, was totally obscured by trees and shrubs; and the evening skies were filled with acrobatic chimney swifts.

From the Allegheny Parks Foundation Webpage
Chimney swifts are beneficial birds to the environment because they are voracious eaters of bothersome flying insects including mosquitoes and flies.

Chimney swifts are migrant birds, returning to our region in April, when they begin looking for nesting sites.

They roost by hanging vertically on the interior of hollowed trees and chimneys, but these options have been lost as dead trees are removed for suburban development and chimneys are capped for more efficient heating.

To counter this loss, the Parks Foundation in collaboration with the Audubon Society, Allegheny County Parks and The Pittsburgh Foundation constructed a number of towers that could serve as nesting sites for the returning birds. The 12-foot towers have a grooved wooden interior that allows the birds to hang and build their nests.