Jan 16 2008

Bridge Birds Get a Nest

Published by at 5:00 pm under Peregrines

Peregrine nestbox at Allegheny River bridge (photo by Doug Dunkerley)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.

3 responses so far

3 Responses to “Bridge Birds Get a Nest”

  1. Libby Strizzion 20 Jan 2008 at 8:42 am

    I went on a raptor survey run yesterday with Linda Wagner and Suzanne Butler(?). Suzanne said she has mixed feelings about peregrines roosting on city buildings. This is because it is not natural behavior for peregrines, she said. We concluded our lunch by saying perhaps a new type of peregrine is joining the regular kind (out of necessity, perhaps).

  2. Tracion 08 May 2009 at 8:28 am

    Kate – did the Peregrine take to this box? I had NO idea this area was drawing so many Peregrines!! Whether it’s natural behavior or not – I don’t care. I’m just glad they are surviving.

  3. Kate St. Johnon 12 May 2009 at 9:16 am

    The spring after the nest box was installed on the 62nd St Bridge PennDOT did major maintenance on the bridge that lasted until autumn. The birds left & did not use the nest box. One peregrine has been hanging out there this spring but it’s unknown whether he/she has a mate.

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