Hi Peter, Birds with black plumages actually may suffer less heat stress
from the sun's radiation than light colored birds. This is because with
black birds, the incoming radiation (photons) are absorbed at the plumage
surface where they release heat. As a consequence most of the heat
generated, flows outward into the surrounding air because the plumage
insulation serves to retard heat flow towards the skin.
In white or lighter colored birds much of the incoming radiation penetrates
deeply into the plumage before it is absorbed and generates heat. In this
case the heat is released deep in the plumage and more tends to flow towards
the skin. For more details you can download a paper entitled " the role of
the plumage in heat transfer processes in birds" at
http://biology.unm.edu/wolf/publications.html.
Some of us spend much to much time thinking about these somewhat or truly
mundane topics
cheers,
Blair
On Wed, Feb 4, 2009 at 12:01 AM, Peter Shute <> wrote:
> That makes me wonder whether birds with black plumage suffer from extreme
> heat more than birds with white plumage. Obviously it's generally not a
> problem or they wouldn't exist.
>
> Peter Shute
>
>
> --------------------------
> Sent using BlackBerry
>
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