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 Both of them are now out of date in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
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