Jan 16 2008
On December 26th I wrote about a pair of peregrine falcons who’ve chosen to nest on a bridge over the Allegheny River. Last year their eggs did not hatch but they still claim the site as their territory. Last week they got a boost toward a successful breeding season with a nestbox provided by the Pennsylvania Game Commission.
Why would people make a nest for peregrines?
Peregrine falcons don’t use sticks to build their nests. In the mountains and at the sea they choose a high, sheer cliff where they look for a narrow, gravelly ledge and dig a depression called a scrape. The scrape provides drainage, keeps the eggs from rolling off the cliff, and creates a rim to support the mother bird so she doesn’t crush the eggs during incubation.
The female peregrine at this bridge probably chose it instead of a cliff because this part of Pennsylvania doesn’t have high, sheer rock faces. And it probably reminded her of home. She was born on a bridge in Virginia.
In any case, there was no gravel last spring so she laid her eggs on a steel beam. She probably coudn’t keep the eggs warm, they may have cracked and then the area flooded. No baby falcons last year.
Peregrines falcons are still endangered in Pennsylvania so the Game Commission visited the site and saw that our lady had tried and failed. They decided she was there to stay and would benefit from a nest box anchored to the underside of the bridge.
As you can see from this picture, she now has a beautiful box, deep gravel and a hood to keep the rain off. We hope she likes it. If she does, we expect to watch baby falcons take off from their river home. Fingers crossed!
Many thanks to Beth Fife and Doug Dunkerley of the PA Game Commission who installed the nest box. Thanks to Doug for providing the photo.