Local breeding peregrine falcons: Success and hardship
June 25, 2014 —
A few years ago, I talked to an old friend who spent his younger years in the Milford, PA area, and among his many exploits were the times he went to the bluffs along the river, just south of Milford, to watch breeding peregrine falcons. The peregrines at Milford and other places were soon in trouble. The state of Pennsylvania reached a peak of 44 pairs during the early part of the 20th century before the species was extirpated in the eastern U.S. Like eagles and other raptors, population declines were attributed to DDT and other organochloride pesticides.
In the 1970s, re-introduction efforts were initiated by the Peregrine Fund and the PA Game Commission (PGC) by using hacking techniques. Though slow to come back, breeding pair numbers increased in subsequent years; last year, there were 40 breeding pairs in the state. Although the majority of pairs chose manmade structures for nesting sites, some pairs did return to historical cliff nests.
One nearby cliff nest is at the Delaware Water Gap. Peregrines were observed breeding at this site since 2003, but for various reasons, failed to produce young. This year, however, the situation changed. Observers were able to tell that at least one young, or eyas, was present at the nest scrape, and the game commission arranged to survey and band the young when they were large enough, at about three weeks of age. The survey was no small feat; the nest location required a rappel of around 200 feet down the vertical face of the cliff.
When the game commission team reached the nest, they found a single three-week-old female, but there was a problem. The eyas had an injury to her right wing, so she was relayed up the cliff and driven to the Delaware Valley Raptor Center (DVRC) where X-rays revealed that the young peregrine had a fractured humerus bone very close to the elbow joint. Bill Streeter, director of the DVRC, explained that the fracture being so close to the joint may affect her chances of being released back into the wild, because the healing process of the bone may cause the nearby joint to stiffen and thus compromise her flight ability. Time will tell with this young eyas; the goal is for her to heal, pass her flight test and be released, perhaps one day to take a mate and have young of her own.