Thanks Ray. This is a biggie - ie good question! There is no simple
answer overarching answer, but in any case I'm not really convinced by
the question; if you start going through familiar species you'll
probably think of more cases where sexes are the same or nearly so than
where they're not (and even a very few examples, such as button-quails
and painted snipe, where the female is the gaudy one). As a somewhat
facile rule of thumb though, the more brightly coloured a male is
relative to his mate, the more socially useless he is - although a good
case could be made for the social value of being conspicuous and being
eaten, rather than letting it happen to the more modestly attired female
sitting on the nest. This is overly simple of course, and there's a lot
more to it, but I'm sure things are already occurring to you!
cheers
Ian
On 21/07/2012 17:34, Sue-Ellen and Ray wrote:
Ian - Thanks for info, most interesting. I have not researched this
area but sounds like others have with some very specific results. You
have started me wondering now why,typically, the male birds have the
brighter colours. I am sure there is a one liner there somewhere.
Ray
-----Original Message----- From: Ian Fraser
Sent: Saturday, July 21, 2012 2:14 PM
Cc:
Subject: Re: [canberrabirds] bedlam (briefly) at Hawker ovals
On 21/07/2012 08:00, Sue-Ellen and Ray wrote:
So on goes the debate – are birds and dogs colour blind!!
Well that one at least we can answer with some certainty. Dogs see the
world in monochrome - like nearly all other vertebrates except frogs,
ungulates, primates and birds. Birds not only see all the colour
spectrum that we do, but far more. Where we have just three pigments in
the cone cells (colour receptors) most birds have four, some five; this
means that they discriminate colour much more subtly than us,
effectively seeing colours, or at least shades, that we can't. Moreover
at least some, probably many, species see shorter wave-lengths than we
can, so see colours that we have no names for - we just lump them
somewhat dismissively as 'ultra-violet'.
I don't suppose this helps the broader discussion, but S-E and R asked
the question....
cheers
Ian
--
Ian Fraser,
Environment Tours; Vertego Environmental Consultancy
PO Box 4148, Weston Creek, ACT 2611
ph: 61 2 6287 4813
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