At 08:16 AM 3/27/98 +1000, you wrote:
>Can you elaborate on what you mean by "preferred colour in some...robins"?
Sorry, to confuse you, Jim. What I mean is that adult male Petroica robin
species have red plumage coloration.
>With regard to the Satin Bowerbird, I would like to believe that the blue
eye colour >isn't a random choice, but predicated on the female's preference
for blue independent >of the male's behaviour. For example, she might
perfer blue because many fruits are >blue...being attracted to blue hence
draws her to investigate the blue items in a >male's bower, selects for blue
eye colour and bluish tinged plumage...and the process >is set into motion.
> In this scenario, the male is also likely to prefer blue. There is also
>the possibility that the blue iris colour is actually used to enhance the
>bird's vision (maybe acting like a blue filter). UV light may also be
>involve here as well. Of course, these are just ideas, but they could
>genrate some very testable predictions.
Seems plausible to me. But why is blue so important in fairy-wrens and red
important in Petroica robins, as opposed to other colours?
>
>You lost me here. Since humans can't preceive UV, how could we view UV
>under a UV source?
The plumage fluoresces when a UV light source is shone on it.
>
>... Eye colour of White-winged Choughs
>Seem reasonable and I wonder if by so doing, the male runs the risk of
>showing off imperfections in the contour, colour, etc. of the eyes? The
>context in which the male performs eye-gorging could perhaps provide some
>clues.
>
Perhaps this is a secondary function, but I suspect the eye-gorging is
primarily used to enhance the red eye stimulus necessary to elicit a
response in females.
**************************************************************
Dr Stephen Ambrose
Research Manager
Birds Australia (Royal Australasian Ornithologists Union)
Australian Bird Research Centre
415 Riversdale Road,
Hawthorn East,
VIC 3123.
Tel: +61 3 9882 2622
Fax: +61 3 9882 2677
Email: S.Ambrose <> (at work)
<> (at home)
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