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]