It's been a while since I offered a new colour in my very intermittent 'colours in nature' series - the last was green, found here, and you can track it back from there.
Way back someone asked me to be sure to do a posting on/in pink one day, and of course I promised to do so; it's been on my conscience (intermittently at least) ever since. Pink is generally a colour based on pigments, and especially carotenoids; we discussed them when we looked at red in nature some time ago, and the same principles apply. In general animals can't produce carotenoids but must take them from food, be it plants, algae or bacteria, then convert them, an outrageously extravagant thing to do just to look good. And never mind the strange Western tradition that reserves pink for girls - in many animals not only do the boys also flaunt it, but in some birds in particular they reserve it for themselves.
A final comment, before the featured birds (I'll offer some other animals next time, then some flowers). I've been very conservative in what I've selected as 'pink'; there is after all a continuum that includes various reds, orange, russet, pink and mauve. Someone in my home sees colours in that part of the spectrum differently from me, so if I'm not cautious I risk domestic scorn at my colour sense...
Pink isn't actually abundant in animals; I guess the logic is that if you're going to go to all that trouble and energy expense you might as well do it properly and go for something really lurid and red.
The most obvious pink bird of course to most people is a flamingo. I talked about the details of flamingo pinkness back here, so I won't go through it again, but it's all due to the carotenoids in its brine shrimp diet.
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| American Flamingo Phoenicopterus ruber, Isabela, Galápagos. Exquisite. |
Some of the other more spectacular pink birds are found among Australian cockatoos.
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| Part of a large flock of Galahs Eolophus roseicapilla, Forbes, New South Wales. These glorious cockatoos are abundant, having spread south-east in the past 50 years with the spread of grain crops and water points. They are often dismissed as 'just galahs', but deserve better. |
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| Major Mitchell's Cockatoos Lophochroa leadbeateri, Bourke, New South Wales. An even more beautiful and much less common cockatoo of the inland. Major Thomas Mitchell was a 19th century explorer who brought them to the public attention by rhapsodising over them. |
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| Both pink cockatoos in one tree, Buldbodney State Forest, central New South Wales. |
Other bird feature pink, rather than fully clothe themselves in it.
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| Western Bowerbird Chlamydera guttata, Alice Springs. The spectacular pink nape is only shown when the bird is displaying. |
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| Pink-eared Duck Malacorhynchus membranaceus, Canberra. A single-species genus of the inland waterways of Australia, the pink 'ear' is really only visible through a telescope - or on a dead bird, which was doubtless how it was named. |
Other species have pink on exposed skin, rather than feathers. This makes sense given the cost of producing carotenoids and the fact that feathers are moulted once a year. But if you refer back to the flamingo portrait above, you'll see that it favours pink all over - bill and legs, as well as feathers.
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| Australian Pelican Pelecanus conspicillatus, Nowra, New South Wales. In part the pink bill pouch is due to blood vessels near the surface, but this is probably not applicable to the bony upper mandible. |
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| African Penguin Spheniscus demersus, south of Cape Town, South Africa. The pink patches here definitely owe much of their colour to blood vessels; when it's hot, more blood is directed there to assist in heat loss, so they're brighter pink. |
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| Southern Caracara Caracara plancus, far southern Chile. It's not a matter of losing heat down there! |
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| Swallow-tailed Gull Creagrus furcatus, Genovesa, Galápagos. A beautiful bird all round, from the pink legs up, and the world's only nocturnal gull. |
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| Black-necked Stilt Himantopus mexicanus, Isabela, Galápagos. |
So, pink is not as easy to find examples of as red, say, but it's worth looking for. Next time, a few other pink-bearing animals, mostly reptiles.
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