Bill Whan says, "I imagine expert aerialists like shorebirds find it more efficient to take flight to avoid trouble than do coots and grebes." I agree - this past Friday at the Hoover Reservoir boardwalk, I watched a juvenile Peregrine Falcon unsuccessfully chase a shorebird - it was that lucky. The falcon rocketed around, would briefly fly out of view then return with steadfast approach, but sill did not succeed in the hunt. At one moment. one shorebird flew straight up while it was being pursued and the Peregrine narrowly missed but quickly put the air brakes on hard, turned around and dove again at the same bird. This shorebird was very efficient with this tactic - because it lived. Perhaps this fast shorebird will survive to pass on its DNA next spring even though the odds are against it. Further though, I wonder if a Bald Eagle really enjoys spooking up birds, rather a shorebird is genetically programmed to flee if it perceives any threat from an above raptor. The shorebird can't afford to take any chances - is there time for a shorebird to evaluate the level of threat from say... a kite being flown by an enthusiast of wind, or from a Bald Eagle which certainly carries the inherent threat that all raptors do? I think there motto is act now, think later. Birds' methods of survival, whether it being successful in pursuit of prey or, on the other hand - escaping becoming energy for another bird for an example is just one of the many reasons that I enjoy watching birds. Its pretty amazing out there and I anticipate spending a lot more time watching shorebirds, and therefore naturally watching shorebirds being taken by falcons and such, and hopefully something like the above mentioned Short-eared Owl. That would be amazing. Also Bill cites of Tinbergen's study of the chicks of Herring gulls freezing when they see certain shapes overhead. In addition to the chick's (and I'm sure many other species as well) demonstrated caution immediately upon hatching -I'm sure that they become even more skeptical of anything overhead as life experiences occur hence being the main reason that I think groups of shorebirds flush up so often and easily. The fact that they don't stay put longer on the mudflats is probably THE biggest obstacle in identifying shorebirds for me. Glen Crippen Burr Oak Lake -----Original Message----- From: Ohio birds [mailto:[log in to unmask]]On Behalf Of Bill Whan Sent: Wednesday, August 29, 2007 4:53 PM To: [log in to unmask] Subject: [Ohio-birds] shorebird responses to raptor-like birds Many helpful remarks on and off the list, and a bit of looking around in publications, prompt the following. Three respondents mentioned the research possibilities of kites/silhouettes, and this is just what Niko Tinbergen did in his experiments with herring gulls, learning that chicks just out of the egg froze when a bird of a certain shape (see Bob Powell's post) passed overhead, and ignored other shapes (The Herring Gull's World, 1960; Tinbergen later won the Nobel prize for this and other ethological studies). Perhaps shorebirds have evolved similar instincts, as raptors are always overhead on their nesting grounds. One person told me of watching shorebirds spooking repeatedly at kites used for body-surfing by human swimmers on a beach. Probably somewhere someone has studied which bird species disturb shorebirds, and which do not, where, and under what circumstances. An interesting and readable paper with some info is at elibrary.unm.edu/sora/Condor/files/issues/v077n01/p0073-p0083.pdf , where researchers spent two winters at the famed shorebird spot Bolinas Lagoon and quantified kills of these birds. Their findings suggest that the largest threat to wintering shorebird flocks must be raptors, and that flocking may reduce an individual bird's chance of being picked off by more than two-thirds. A single merlin accounted for a lot of shorebird mortality, and kestrels took a toll (the study took place 1971-73, when peregrines were a small part of the picture). Harriers were not often present, but took shorebirds, even coots. Accipiters, buteos, and white-tailed kites, though present in the area, played a very small part. Short-eared owls, however, subsisted on birds for 51.7% of their diet in one winter and 87.9% the next. Though less numerous, long-eared and great horned owls did a lot of damage as well. Surely owls did not rely on raw speed to catch shorebirds! The researchers estimated that raptors took 20.7% of the dunlins, 11.9% of the least sandpipers, 7.5% of the western sandpipers, and 13.5% of the sanderlings present over one winter. I imagine expert aerialists like shorebirds find it more efficient to take flight to avoid trouble than do coots and grebes. They also seem to know that an individual by itself is in greater danger, so panic on the part of one becomes a movement by all. We all have seen the "dreads" of terns--those mass flights they so often undertake that seem provoked by invisible threats, or maybe sheer exuberance. And I think Craig's point is well taken, that birds just passing through will take cues from the locals as to the danger posed by certain raptors. We can't forget that this time of year many Arctic shorebirds in Ohio are juveniles traveling without experienced adults, and may be seeing their first eagles... Several people have described redoubtable feats of hunting by eagles, but none seems worth the trouble for a scrawny shorebird. A haunch of road-killed deer or filet de carp is so much more satisfying. Sometimes you get the feeling in the field that eagles delight in throwing their weight around, actually, just wreaking havoc for the heck of it... Bill Whan Columbus ______________________________________________________________________ Ohio-birds mailing list, a service of the Ohio Ornithological Society. Our thanks to Miami University for hosting this mailing list. Additional discussions can be found in our forums, at www.ohiobirds.org/forum/. You can join or leave the list, or change your options, at: http://listserv.muohio.edu/scripts/wa.exe?LIST=OHIO-BIRDS Send questions or comments about the list to: [log in to unmask] ______________________________________________________________________ Ohio-birds mailing list, a service of the Ohio Ornithological Society. Our thanks to Miami University for hosting this mailing list. Additional discussions can be found in our forums, at www.ohiobirds.org/forum/. You can join or leave the list, or change your options, at: http://listserv.muohio.edu/scripts/wa.exe?LIST=OHIO-BIRDS Send questions or comments about the list to: [log in to unmask]