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General Science => General Science => Topic started by: Elvis Presley on 14/10/2010 11:22:11

Title: Why do some wading birds have yellow legs?
Post by: Elvis Presley on 14/10/2010 11:22:11

Why do some wading birds have yellow legs? There must be a good reason.

Title: Why do some wading birds have yellow legs?
Post by: BenV on 14/10/2010 11:26:11

That is a very good question - you would assume that there would be an advantage to having dark coloured legs, so that passing prey wouldn't see the obvious evidence of your presence.  I don't know the answer, but I hope someone will come along soon who does.

Welcome to the forum!

Title: Why do some wading birds have yellow legs?
Post by: Elvis Presley on 14/10/2010 11:29:21

Thanks.

I was here a while back as 'Herman Melville', but missed you all and wanted to return. Are Neil, Make It Lady, Variola, Don, etc still all here?

Title: Why do some wading birds have yellow legs?
Post by: RD on 14/10/2010 11:49:11

Quote from: Elvis Presley on 14/10/2010 11:22:11

Why do some wading birds have yellow legs?

They are also available in red (http://en.wikipedia.org/wiki/Common_Redshank) and brown.

Quote from: Elvis Presley on 14/10/2010 11:22:11

There must be a good reason.

If the colour is genetic*, a mutation can persist even if there is no advantage, provided it is not a handicap,
(cf being "a ginger" (http://www.youtube.com/watch?v=F_DVHUEjnuU)  [:)] ).

[* rather than a consequence of its diet ]

Title: Why do some wading birds have yellow legs?
Post by: Geezer on 14/10/2010 20:03:30

How gauche! Don't they know you should only go wading in green wellies?

Title: Why do some wading birds have yellow legs?
Post by: Don_1 on 15/10/2010 13:53:26

I don't know if there has been any study to find any particular significance to the colour of wading birds legs, but you are quite right to say that some have yellow legs. There are also some with orange and some with red legs, as well as the browns, blacks and greys.

The first point to consider is that many wading birds are migratory, so leg colour is unlikely to be as a result of habitat, since the summer and winter habitats may be very different.

Would highly visible legs frighten off prey? Well maybe they would, if your prey were fish. But yellow legs do not seem to impede the highly successful White Faced Heron, so that's one theory blown out of the water. (Pun intended). If you are looking to catch fish, the ability to keep still is far more important than the colour of your legs. Egrets, Herons and other such birds can be very patient. They also have the advantage of throwing some shade on the water which attracts fish. Both the Tricolored and the Black Heron make full use of this fact by spreading the wings, in the case of the Tricolored and forming an umbrella effect, in the case of the Black Heron. Strangely, these two species of Heron do not have yellow legs.

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Black Heron

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Tricolored Heron

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White Faced Heron


Of course not all wading birds prey on fish. The Redshank, with its orange to red legs has a diet of insects, insect larvae, earthworms, mollusc's and crustaceans. The Purple Sandpiper, with it's short yellowish legs, has a diet which consists of winkles, insects, spiders, crustaceans and vegetation. In the case of these two, leg colour, and therefore visibilty, is not a consideration.

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Redshank

Title: Why do some wading birds have yellow legs?
Post by: Elvis Presley on 15/10/2010 21:07:28

Thanks, Don.

Title: Why do some wading birds have yellow legs?
Post by: Ethos on 16/10/2010 17:09:04

Elvis is in the house, and I thought he had passed on????????????

Title: Why do some wading birds have yellow legs?
Post by: Don_1 on 16/10/2010 17:53:20

So did I, but it looks like he's still twitching.