It has been several years since I've taken my anatomy & physiology
courses, but somewhere along the line I thought that I had been taught
that the legs of birds in general were much less vascularized than, say,
the legs of mammals. Less vascularization would tend to reduce heat
loss, etc. I do know that small cuts to the birds' feet/legs that result
from mist-netting tend to bleed less than similar cuts to my toes/fingers.

I can see that legs being wetted during feeding, etc would tend to
radiate heat more than dry legs, and that only makes sense. However,
waterfowl, grebes, loons, etc spend considerable time with their legs
dangling in an excellent heat conductor - 36 to 50 degree (F) water. If
the legs of birds were such good thermal conductors, I would imagine that
water birds in general would be thermally stressed - and either they
aren't or they've developed some other mechanisms to compensate for the
heat loss. (As a person afflicted with male pattern baldness, I can
sympathize with heat loss from a highly vascularized portion of my body
to a cool/cold environment)

I would be interested in reading Piersma's paper, Stuart, if you could
provide a reference.

Thanks.

Jon. Anderson
Olympia, WA
anderjda at dfw.wa.gov

On Tue, 2 May 1995, Stuart MacKay wrote:

> Theunis Piersma's work on Red Knot revealed that their legs make fantastic
> radiators and help the bird considerably when dealing with tropical and
> sub-tropical conditions. Looks like legs are pretty useful things ;-)