On Sun, 8 Aug 1999 20:57:07 -0700 "Kelly Cassidy" <lostriver at seanet.com>
writes:
>
>I went to the Project Pigeon Watch page,
http://birdsource.cornell.edu/ppw/watizppw.htm recommended by another
>tweetster recently. It says: "Project PigeonWatch is an international
survey of pigeon flock coloration and behavior. >Its primary goal is to
learn why pigeons exist in so many different colors.
>
>Are some colors better for attracting mates?
>Are some colors better at hiding from predators?
>PigeonWatchers will help us find out!"
>
> In the page called Why Watch Pigeons, Andre Dhondt offers a little
more detail on hypotheses about why pigeons >are so colorful. He
suggests that the lack of predation in cities allows odd-colored pigeons
to survive (essentially >the removal of the selection pressure followed
by genetic drift theory). He also suggests that pigeons may prefer
>certain colors in mates and or that certain colors are associated with
dominance and hence those dominant birds >get to eat more.
>
> I thought all this was interesting because I have always assumed,
without giving it much thought, that Rock Doves >were so variable in
color because people have a tendency to notice the odd-colored bird in a
flock and are more >likely to toss the food in that direction. Hence,
the bird that is most different from the crowd will, on average, get
>more food. The low level of predation on pigeons in cities is
presumably not high enough to offset the value of >more food.
>
> But then, if the preferential-feeding-by-people hypothesis is correct,
then one wonders why House Sparrows have >not gotten more colorful.
Maybe they aren't as dependent on hand-feeding? Or they have so many
more predators >that more food doesn't offset higher predation?
>
> Kelly Cassidy
> Seattle

Tweeters,

I'll humbly offer this list the same observation that I gave to the
operators of the above mentioned web page when I visited it. Pigeon
fanciers in large urban centers regularly lose birds to the feral flocks
in their vicinity. I suggest that this may account for some (or even
much) of the variety in those city flocks, since the majority of
fancier's flocks consist of fancy colored birds, and thus the regular
infusion of fancy colored birds into the gene pool of these city flocks
keeps the numbers of fancy colored birds in those feral flocks high. It
has been my personal observation that flocks of pigeons (rock doves)
living/breeding in isolated locations away from urban centers (for
example, the flock at Palouse Fall State Park or the flock that nests in
the cliff at Morgan Lake in Adams County) eventually contain very few odd
or fancy colored birds. It is easy to imagine that this due in part to
increased predator pressure in these locations, but I also suspect that
without the regular addition of odd or fancy colored birds to the gene
pool of these flocks, that a genetic predisposition for the color and
pattern that this species had, prior to it's domestication and the
influence of selective breeding, may reassert itself.

Dennis K Rockwell, Kennewick, Washington
denniskrockwell at juno.com

If you would know what the Lord God thinks of money,
you have only to look at those to whom he gives it. Maurice
Baring(1874-1945)

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