At 12:19 10/2/98 -0800, Kelly Cassidy wrote:

>Eagle behavioral differences when people are present are noteworthy,
>but don't necessarily indicate an effect on productivity. Feeding and
>activity patterns of Canada Geese and Mallards in Seattle parks are
>undoubtedly affected by joggers, kite-flyers, dogs, softball games, etc.
>(There are times when they actually have to FLY!) Would their
>productivity be higher without disturbances? COULD it be any higher?
>
>David Manuwal suggested there might now be a bimodal pattern to eagle
>responses to people: some eagles will ignore almost anything people do,
>others are still very shy. I suspect that in a bird as long-lived as an
>eagle, learning might be happening, too.
>


I've often wondered if the reaction of the eagle is also due to the
behavior of the people. For example, if you approach an eagle on foot, you
can get a lot close if you aren't looking directly at the bird but are
looking away from it. Perhaps a direct look is considerd a threat (You're
looking right at me so you must see me) while a side-ways glance is not
considered a threat (You aren't looking at me so you must not see me). Noise
may be another factor. Anglers tend to be quiet so they are ignored.
Perhaps a raft full of birders are more threatening than a raft full of
non-birders because the people are all looking at the eagle.
I definitely think learning is a part of this as well. Immature
eagles seem much more tolerant than adult eagles.
I think season is important as well. Obviously a breeding bird near
the nest is going to be more threatened by an approach than one in the
non-breeding season.
I don't have any data or research on these possibilities. It would
be difficult to test (all that squishy data). I can relate my own
experiences; countless times trying to get a better picture only to have the
eagle detect me and fly away eventhough there were many other people in the
area, some closer than I was.




Deb Beutler
Department of Zoology
P.O. Box 644236
Washington State Univerisity
Pullman, Whitman Co., WA
dbeutler at wsunix.wsu.edu