Not only vultures, ostriches and many other birds that live in hot habitats also have dark feathers. Considering their extremely hot habitat and there are not many objects with such a dark color, why do they have black feathers?
Black colors can absorb sunlight better than other colors so that it can increase body temperature (like in penguins). Besides that, it's hard to camouflage since black color is easily seen in their habitats, which mostly light-brown colored.
Hi, there are various hypotheses which we reviewed in the attached paper. best wishes, jon
Article The adaptive significance of dark plumage for birds in deser...
Hi Angaddia,
Your question seems to suggest that all vultures live in extreme hot climate zones.
This partly true, but certainly not a general rule. For example in Europe alone, several species of vulture live in (more) mountainous areas, with snow in winter. These species don't fly south in winter. They stay in their local territories. A lot of these species are black and white feathered and feed on sheep and smaller game as well.
What about the dark plumage of these birds in a temperate to cold climate? Adaptation to a hot climate? I don't think so.
Cheers,
Frank
Hello Frank, thanks for your correction. I think in temperate to cold climate they use dark plumage to absorb sunlight so that they can stay warm, then I wonder why birds in hot climate have dark plumage too. Wow I get new information here that they can be found in snowy area too. Cheers :)
This is actually a pretty old question in thermal biology. Another version of the problem is "why are beetles in the Namib desert black?" Most of the animal physiology textbooks should give substantial insight as a starting point. Withers (1992) "Comparative Animal Physiology" is my usual starting point.
Anyway, the crux of the thing is that black is a pretty good colour in both cold and hot environments, depending on the aim of the game. In the cold it's a very good colour for absorbing heat (hence basking in ectotherms is often facilitated by physiological darkening). The thing is, through, in hot conditions it's a very good colour to dump excess heat. Since black surfaces become so much warmer than the environment heat can easily transfer from the surface by convection or conduction. So the real question you're asking here is what's the evolutionary driver for the vultures in these hot environments? Are they aiming to absorb and retain heat, or are they aiming to dump it? And of course this depends on their altitude, because during high altitude soaring they probably want to retain heat, but at low altitude they probably want to dump it. Hence, for a vulture, black is probably the best colour they could be because they can play both ends off against the middle.
This is, of course, all my general speculation. If you read some general textbooks you should be able to see whether my broad understanding is correct. Also, if you read the paper attached by Dr Blount (and references therein) you'll get a more detailed understanding specific to birds, and of course the whole thing is flexible to the stressors of ecology and evolution, as suggested by Dr. Veroustraete. My caution here is that even a simple question like this often indicates complicated patterns, and that if you get trapped in to narrow a set of assumptions, such as "black is a good colour for cold environments" you can often miss powerful insights.
Anyway, I hope that helps. I've suddenly realised that this reads like a lecture, and I'm probably not qualified to give one. Cheers
Sean
Hi Sean :-) of course i've read the paper attached by Dr. Blount. Thanks for your explanation, that's really helpful ^_^
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