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Showing posts with label sexual selection. Show all posts
Showing posts with label sexual selection. Show all posts

Whydahs and Canaries, Oh My!

Tuesday, August 21, 2012

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In the grasslands outside Nelspruit, South Africa, I enjoyed a day birding with my dear friend Peter Lawson. Lantana was running wild in the tangled grasses, and yellow-fronted canaries were feeding on its fruit. Blue is traditionally a bird-attracting color; plants that "want" birds to take their fruit make blue fruit.
No wonder lantana spreads like mad!


Yellow-fronted canary with common waxbill. The waxbills are just after grass seed.

The stars of the show this day were the pin-tailed whydahs. I'd seen whydahs in winter in South Africa, when they look like little brown house sparrows. Nothing prepared me for seeing the males in full summer raiment, breeding plumage.


They chose prominent perches all around the fields, showing off their spectacular tails.


That's a lot of tail for a little finch to carry. Must be some sexual selection at work here. The boys with the longest tails get the most mating opportunities...something like that must be going on.


Here's the little gal who decides how long the tails will get: the female pin-tailed whydah.


Yes, the males are spectacular, but the females are the ones driving the evolution of their wonderful tails. If female birds decide they like long tails and mate preferentially with long-tailed males, Nelly bar the door. Eventually you get a 5" bird with a 15" tail! And the males were dancing like mad, buffeted by a fresh warm breeze, their tails making sinusoidal curves as they danced.


O glory, what a bird. They landed with a flourish on a prominent high perch, letting their tails do their thing in the wind.


I love this shot of a male whydah dancing above a female (hidden in the grass). He's fluttering in one place, and he closes his wings to his body and just hangs in the air between flaps, looking like some kind of crazy wiglet suspended above the grass tops. Bird displays just knock me out. I can only imagine how cool it looks from below.


Resting between dancing bouts.


And a rattling cisticola cheering them on.

The Madness of Martins and Elk

Monday, April 23, 2007

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On my drive up to Bellville, Ohio on Friday, April 19, I stopped at a favorite haunt: Zanesville Pottery. This is where I get a lot of my bonsai pots and the Ohio-made birdbath pedestals that I use for orchids and planters. Didn't find much this time but I had fun looking, and I decided to cruise north on old U.S. 40, which parallels boring old I-77. Boy, am I glad I did. The first thing I saw was a flock of birds overhead, with a distinctive shape. Gol-darn. Those are martins! After the dire news I'd heard of an almost complete die-off of adult male purple martins (many of whom arrived on territory just before the April 11 cold snap), it was manna to see these birds overhead. I checked the rearview mirror, slowed to a crawl, and craned my neck to see if there was a colony nearby.

There was.
Simply the most magnificent purple martin colony I'd ever seen. Most of the nesting gourds home-grown; the houses, nay-- castles, all home-built. More than eighty martins swirled and chattered around the immaculately-kept abodes. The gourds were most popular (martins love swinging gourds for their roomy insides, and they tend to raise larger broods in gourds, too!)I pulled over and started taking pictures. I saw a woman fetching her newspaper at the bottom of the driveway and hailed her. I asked if it would be all right for me to photograph her colony. She invited me up in the driveway, and we struck up a nice conversation. The work was all her husband's, she said, and the colony has been extant for 10 years. There were a few house sparrows and starlings around, and she confided that her husband shoots them from the blind provided by a basement window. While this might upset some readers' sensibilities, I can confidently say that there are probably no successful purple martin colonies that are not protected by some form of stringent sparrow and starling control, whether trapping or shooting. The two cannot co-exist, thanks to the house sparrow's nasty habit of piercing martin eggs, throwing babies out, and pecking adults to death. Blaaah. They are vermin, and have to go.

Friday was the first nice day in about two weeks. The martins were chortling and basking in the unaccustomed spring sunshine. They looked so happy, and they sounded happy, too. I was so happy to have found this wonderful spot, an ordinary little white ranch house with owners who care about purple martins, enough to put this kind of work and dedication into them for a decade. Mrs. Martin (not her real name) told me that they had taken their ugly TV antenna down but the martins missed it so much they put it back up, in the middle of the colony. It was festooned in birds. I asked the woman, who might have been in her sixties, if they had anyone in mind to take over the colony when they could no longer care for it. She shook her head sadly. I wondered if someone might buy that house just for its colony. A long shot, I know. But what a gift to the universe, to put purple martins in the sky.She asked me if I'd like to see the reindeer. Yep, in addition to hundreds of martins, they keep reindeer. Very fat, well-fed reindeer. The cows had sweet faces. The bull looked positively malevolent. If I had about 75 pounds of antler on my head, I'd be cranky, too. She told me that when the antlers harden off, they have to dart the bull each year and saw them off, because he's so evil. He has hooked her husband before and nobody wants that to happen again. He reminded me of an Irish elk, the extinct cervid that lived in what is now Ireland, that is thought to have died out because its antlers got too massive and the males could no longer survive. Sexual selection gone wild. The implication being that the females mated selectively with the bucks with the biggest antlers, and there was intense selection pressure for big antlers, and things just got out of hand. The bucks got bogged down in the peat and died. Hmmm.

Whether or not you buy this evolutionary just-so story, I have definitely seen some people who are responding to selection pressure by the opposite sex in ways that are not adaptive. Like women, trying to run on stilettos, and falling down and breaking an ankle. Or wearing skirts so short they can't even bend over or sit down. Or acting dumb and helpless and trading solely on their looks. Or putting bags of silicone and saline on their chests. (How do you nurse a child around that?) Like men, trying to drive the hottest cars the fastest, thinking to impress women, and wrapping themselves around telephone poles. Jumping off bridges secured only by bungee cords. Shooting whitewater rapids nobody ought to mess with. Irish elks, all. Pfffffft. That's my lecture for the day. And I plod off to cook dinner for the bearers of my genetic material, wearing homely, sensible shoes and khakis, and thinking about Irish elk.
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