Peregrines come back

SCOTT RANDO
Posted 10/26/18

Historically, the peregrine falcon nested in this region through the early part of the 20th century. However, the peregrine suffered the same plight as the bald eagle; breeding failures became common …

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Peregrines come back

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Historically, the peregrine falcon nested in this region through the early part of the 20th century. However, the peregrine suffered the same plight as the bald eagle; breeding failures became common due to the introduction of the pesticide DDT into the environment. According to the New York State Department of Environmental Conservation (NYSDEC), the peregrine was no longer a nesting species in New York by the early 1960s.

In the 1970s, peregrine falcons were re-introduced by the release of captive-bred birds, and the first nests were found on two bridges in New York City in 1983. This species has recovered somewhat since the re-introduction effort, but not to the extent of the success of the bald eagle. In 2014, when the last statewide count was taken, there were 125 territories, of which 63 were active; 29 young were successfully fledged from active nests that year. At this time, the peregrine falcon is still listed as an endangered species.

Like the two original bridge nests, many of the peregrine nests found after the re-introduction effort have been on man-made structures such as building ledges and superstructures of bridges. A few nests were established on traditional cliff sites in the Adirondacks and other areas, but they were the exception. It was met with some excitement when a territory in our region, which was occupied last year but did not produce young, showed signs that young were present during May of this year.

This nest site (its location will remain confidential at the request of the NYSDEC) is a cliff nest near the top of a rocky outcrop. Peregrine falcons locate their nests, or “nest scrapes,” near the top of cliffs, usually on a ledge that is flat and wide enough to accommodate the adults and the activities of the young, or “eyases.” Although these nest scrapes are largely protected against predators due to their location, they have unique hazards; a few years back, a three-week-old eyas was found by a PA Game Commission banding team with a broken wing. It was surmised that a loose rock along the cliff fell and injured the eyas, the only young found at the site in PA that day.

As to our peregrine family, it was difficult to tell at first whether they had initiated incubation or not. Due to the setback of the nest scrape from the edge of the cliff and the observing location, it was impossible to see if an adult was incubating eggs or not; but the fact that the adults were flying back to the same location on the outcrop at somewhat regular intervals held promise that eggs were present.

Around mid-May, there was another promising sign. Faint begging calls from at least one eyas could be heard. On further listening during that early time, two young could be heard crying at the same time. Occasionally the back of an adult could be seen near the nest if it was out far enough.

As the next week rolled around, there was an increase in prey delivery to the nest by the adults. There were more frequent food exchanges; one adult, usually the male, would approach with prey and transfer it to the female, who would then bring the item back to the nest for the young. These were frequently mid-air exchanges that were thrilling to watch. With peregrines, the female does the brooding and feeding of the young. It also seemed that the crying of the young was getting a little louder, and intensified when either adult approached the nest.

On June 1, the first eyas was actually spotted; it had walked out close to the edge of the cliff and gazed out on what would soon become its aerial training area, turned around and disappeared as it walked back to where the nest scrape was. The eyas appeared to be about three weeks old, down covered but with a lot of dark contour feathers poking through the down. By the following week, two young were seen simultaneously, along with a wingtip of a third. There were three young so far, but we could not rule out another; female peregrines typically lay a clutch of two to four eggs.

During the first and second week of June, the contour and flight feathers filled in, and they started to exercise their wings, and on the 15th of June, I arrived to the site to discover the young crying from further down the cliff. Soon after arriving, I saw a peregrine fly really low, and land on a rock that was close to the ground, not the typical behavior of an adult. A look with binoculars revealed it to be one of the young peregrines. Continuing to survey the area, there was an adult perched down the cliff from the nest scrape looking up. Following the adult’s gaze, I discovered that there was still one young near the nest scrape, apparently not yet fledged. The adult continued to stare upwards at the youngster, not turning away. There must have been a lot of communication conveyed in the adult’s stare, as the young launched itself off the edge of the ledge and ended up on a nearby tree further down the cliff.

The last two weeks of June saw the young fledglings in the air more often as they improved their flying skills. Their flights were usually announced by one or more young vocalizing, followed by one or more young flying. They were soon at play sparring with each other, rolling and displaying talons; sometimes, they would lock talons for a short time. During this time, I also saw adults carry prey by the cliff and young try to snatch it in mid-air. As time went on, the young got more skilled and were successful on their first try. This is another skill that is used by breeding adults: mid-air food transfer.

By July, the young were frequently flying en masse, and the opportunity arose to get a good count of total young fledged. Ultimately, I counted four young, plus the two adults. This was a productive year for this pair, and the young all made it past the initial point around fledging time when injuries and mortality can occur. On average, six out of 10 peregrine falcons do not survive their first year of life.

As humans entering the peregrines’ habitat, we should be good stewards of the peregrines in order to help in their comeback. If you are climbing or rappelling, or otherwise near a breeding area, please obey any warning signs from state wildlife agencies. Not only is it bad for the peregrines, but it is very distracting trying to work a proper rappel while an angry adult peregrine dives at your head trying to draw blood.

Peregrine Falcons, nature, upper delaware, birds of prey, falconry, raptors

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