Peregrine drama in Beaver County

Ohio River railroad bridge, Beaver, PAThe peregrines in Beaver County settled a score today.

Last year Scott Gregg confirmed a peregrine nest at an Ohio River bridge in Monaca.  This spring, not only are his peregrines at Monaca but a pair was seen mating at this railroad bridge in Beaver only 1.25 air-miles away.

Are there two peregrine nests in Beaver County?  We met Scott Gregg at the railroad bridge this afternoon to find out.

At first there was no activity, then three peregrines chased each other from the bridge to the hillside.  One was an immature bird, brown instead of gray.  The adults made a show of strength by lowering their talons but there was no intense aggression.

After they flew away we decided to split up and monitor both bridges.  Scott gave me a walkie-talkie and drove to Monaca while the rest of us stayed at the Beaver bridge.

As soon as he arrived at Monaca, Scott radioed that there was no activity whatsoever over there.  Yet almost immediately in Beaver we saw three peregrines zoom past in a chase: an adult female and two immatures.  It was hard to see the immature peregrines with the brown hillside as a backdrop but it was clear that the gloves had come off.  This was a real fight.

The adult female chased the immature female and grabbed at her with her talons.  The third bird flew with them, following every move.  Under pursuit, the immature female flipped over to defend herself but the adult female grabbed her feet.  Locked together they tumbled in a ball toward the river separating at the last minute before they hit the water.  The adult female would not give up the chase, forcing the other two downriver in hot pursuit.  After they disappeared from view an adult male peregrine flew off the railroad bridge and followed them.  Four peregrines!

A little time passed and the adult female peregrine came back and landed on the tower of the railroad bridge.  “She’s going to mate,” said my friend Karen.  Quite a prediction!
In a few minutes the adult male peregrine returned from the chase and the pair copulated on the railroad bridge tower.   Meanwhile, in Monaca Scott was bored.  He saw no peregrines at all.

So what does this mean?

I think there’s only one peregrine nest in Beaver County – at the Monaca bridge.  The Monaca pair sometimes mate on the Beaver railroad bridge as a way of claiming it as part of their territory.  An immature female peregrine showed up and the pair did not drive her off because she looked too young to nest, but when a fourth peregrine arrived it was more than the Monaca peregrines could take.  Today they drove away the others and proved they own both bridges by mating in full view on the railroad bridge.

My husband says “Violence is an aphrodisiac for peregrines.”   I wonder.

[p.s. You can tell it’s peregrine season.  My blog is nearly “All peregrines, All the time.”]