On 8/28/07, David J. Horn <[log in to unmask]> wrote: > > > Some enterprising student could look into this by flying model aircraft, > or > boomerangs, of various shapes and speeds over flocks of foraging > shorebirds, > and quantifying the response. > > I remember reading in a long out-of-print introduction to ornithology (see below), about a pre-WWII experiment along just these lines. The investigator constructed a cardboard planform shaped more or less like a cross, which he then passed over collections of constrained birds. When the shape was passed over the birds with the long end leading (like this, left to right: -|--, a sort of swan-like shape), there was little or no reaction from the birds. However, when the shape was passed over the birds with the short end leading (that is, like this: --|-, a vaguely hawk-like shape), there was wholesale panic among the subjects. The conclusion was that the birds had an innate fear of generalized hawk-like shapes that were moving. I read about this almost fifty years ago in one (or both) of the following books: Aretas A Saunders, Introduction to Bird Life for Bird Watchers and/or A Guide to Bird Watching, by Joseph J Hickey. Both of these books are still available from specialty booksellers. Both of them are now out of date in many ways, but in their time they provided a good way to move from an interest in identifying birds to a deeper appreciation of birds as animals and their many remarkable adaptations. This is a niche which is sadly unfilled today. Cheers, Bob -- Robert D Powell Wilmington, OH, USA [log in to unmask] http://rdp1710.wordpress.com Nulla dies sine linea ______________________________________________________________________ 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]