Hi All,
Coloration of a bird's integument, including the legs, feet and mandibles is
a result of concentrations of pigments, mostly carotenoids and melanins in
the epidermis. Several studies of a range of bird species have shown that
seasonal changes in coloration of the integument (colour, intensity and
extent of coloration) reflect the reproductive hormonal status of an
individual, whereas structural coloration (bill, leg & foot scales) is an
accurate signal of the health and condition of the bird.
I notice that in the links to photos that Jenny posted, the corvids not only
had a "cream wash" to the feet and legs, but also to the mandibles (bill).
While that may be a result of abrasion or dust, as indicated by others on
Birding-aus, I suggest that it could be an indication of poor health and
condition of the birds and/or that they are advanced in age.
Kind regards,
Stephen
Stephen Ambrose
Ryde NSW
-----Original Message-----
From: Birding-Aus On Behalf Of
Jenny Spry
Sent: Sunday, 3 August 2014 8:43 PM
To: Shirley Cook; Stephen Debus; birding-aus
Subject: Fw: Raven and Crow feet
Hi all,
Thank you Shirley for passing the message on and thank you Steve for your
input. I have done a bit more research and there are some very good images
on the International Bird Collection website. Possibly the best is of a
Torresian Crow at
http://ibc.lynxeds.com/photo/torresian-crow-corvus-orru/drinking
Another good image is Mat Gilfedder's of a Little Crow at
http://ibc.lynxeds.com/photo/little-crow-corvus-bennetti/adult-bird-perched-
fence
Looking at these where the colouring, certainly not "yellow" as I first
thought but a "cream" type colour, can be right up the leg. My guess is that
the legs have lost the black outer coating either from age or by abrasion
from the habitat the bird is living in. I wonder if the pale colouring only
develops in inland areas where there is plenty of dry and abrasive
conditions?
cheers
Jenny
http://jenniferspryausbirding.blogspot.com.au/
On 3 August 2014 15:13, Shirley Cook <> wrote:
> Dear all,
>
> Here is a comment from Steve Debus
>
> Regards
> Shirley
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