Date: 6/13/18 9:11 am From: Wayne Hoffman <whoffman...> Subject: [obol] Re: Oystercatchers
I feel a need to comment on several points from this thread.
First Point. Are Peregrines still being hacked in Oregon? I doubt that there are still eggs being hatched and babies being raised for this purpose in Oregon, but the person to ask for a definitive answer would be Bob Sallinger at Portland Audubon. However there probably are rescued and rehabbed birds being released from time to time, just as with other raptors.
Second Point. Re release at Crater Lake. In the early 1970s there were no known (or at least acknowledged-there was lots of paranoia about falconers) active nests in Oregon. The first one found was at Crater Lake, about 1977. This was a natural nest, apparently not the result of hacking birds. It is a mistake to think that "There is obviously no food supply in the national park." Peregrines can and do subsist on land birds as well as aquatic ones. I have extensive prey data from the Yaquina Head nestings, and at this site they eat more land birds than aquatic ones. The bulk of the land bird prey are Starlings and Eurasian Collared Doves, but they have also brought in thrushes, an occasional Band-tailed Pigeon, a Western Tanager, a few Crows, etc., as well as a Short-tailed or immature Long-tailed Weasel, and several chipmunks and smaller rodents. I have seen reference elsewhere to Peregrines that fed extensively on Gray Jays.
Third point: Lars wrote "...none of them the result of human effort—just spontaneous response to the opportunity. That is to say, the expensive efforts bore no results." Indeed in some parts of the country, urban-hacked birds seem to only be producing progeny that nest in urban situations, and not re-populating historic cliff sites. In Oregon not all hacking was in urban areas, and hacked birds did contribute to the current population. I say this because I have photographed many Peregrines to study plumage and other physical characteristics, and I see far more evidence of mixed parentage than I would expect if the hacking programs did not contribute to the population.
Fourth Point: I believe Jeff Gilligan is correct in his belief that there is no longer any reason to hack Peregrines in Oregon (or anywhere else in the Northwest). In my and colleagues extensive observations of the Peregrines at Yaquina Head and elsewhere on the central coast, we see much evidence of a surplus of adults, such that the existing pairs with territories are frequently challenged by rivals trying to take over the territory/nest site. In late winter and spring we sometimes see several different Peregrines visit and be chased off in the course of a single day. We have seen several instances of extended efforts to usurp the site. Several years ago a banded female spent quite a while trying to replace the breeding female, but eventually ended up dead, I suspect killed by the established breeding female.
In 2015 the breeding male disappeared and was replaced by the current breeding male (we considered naming him Claudius) right at the beginning of incubation. The usurper had been seen at the site for a few weeks and showed signs of injury at the time the breeding male disappeared, but was able to pair quickly with the breeding female and fed her throughout incubation.
I realize that this is the same kind of evidence I cited for the Oystercatchers - "surplus" nonbreeding adults suggest a healthy population - but I think it is a reliable indication of more-than-adequate recruitment to balance adult mortality.
On 6/13/2018 5:57:29 AM, Lars Per Norgren <larspernorgren...> wrote:
At one point I heard that there were three pairs nesting inside the city limits of Portland, none of them the result of human effort—just spontaneous response to the opportunity. That is to say, the expensive efforts bore no results. A fortune has been spent in south Texas to reintroduce Aplomado Falcons. Great Horned Owls eat them as fast as they are released. Money would be far better spent on chainsaws and their operators to remove the mesquite that harbors the owls, compromises the grassland. Not nearly as glamorous, but I like a bang for my endangered species buck. These high profile black holes pale in comparison to the Steller’s Eider. A graduate student working on their recovery program on Alaska’s North Slope told me it has been the most expensive program per bird to date. Two years ago 360 fertile eggs intended for cross fostering were never placed in nests.
I met a biologist at Thompson Reservoir in June of 1982, when the Peregrine hacking program was in its infancy. At that time the first site planned for Oregon was Crater Lake. There is obviously no food supply in the national park, putative parents would have had to commute to Klamath Forest marsh. But there were many human visitors to the desert cliffs of Crater Lake, making it a high profile endeavor. lpn