Monday, July 30, 2007

Bird Eyes with Wrinkles and Behavior Bits

In the comments section when the Goldfinch last appeared, is a question from James, who asked if I'd happened to notice the wrinkles under the male Goldfinch's eyes and whether or not it was a sign of age. See below for a closer look.

Mr. G. certainly does seem to have a crease under his eye. Whether it's a sign of age, is like everything else in biology--it depends. Because rarely does anything have only one factor involved in it's causation.
Guess what? Not really a surprise but here is very little in the literature about bird wrinkles due to aging. There is some information about elderly parrots but unfortunately my photograph of the 80 something year old heavily wrinkled Macaw is in New York with the bulk of my photos, as opposed to here in Wisconsin so you'll just have to trust me on this.
Aged parrots do get a network of wrinkles around their eyes as the years go by and because there is a circle of skin without a heavy feather cover around the ocular orifice, you can see the wrinkles clearly.

Let's take a look at Quicksilver. He's a young African Grey so he doesn't have age wrinkles but like humans he will get "circles under his eyes" just as we do, when he's stayed up too late. Not the best photo of the issue under discussion as the same problem applies as above but look closely. Focus on his black pupil, start looking outwards, discount the iris which is pale beige, almost white and then you get to the circle of exposed skin, a pale gray, then a white circle beyond that. Focus on the pale gray area below his eye and you'll see a bit of a discolored bag. He's not old; he's just tired.

Speaking of tired, check out Isolde of the Cathedral Hawks on the right. This was during the period of time when she was looking under the weather. Three eyasses could well tire a mom out but also a female hawk is going through any number of cascading hormonal changes during the nesting season. That too could have an effect.
This was the day when the Crows and the Kestrels were attacking at the same time. She roused herself to defend the nest but look at her eye. Compare it to Tristan's. Isolde has a definite crease and puffiness.
Now I might not have thought of the hormonal changes except for an episode involving the resident Goldfinch pair that I observed yesterday.

It started in the garden just a touch before sunset. As you can see the sun is quite low already. What you may not be able to see but what I was observing was the female Goldfinch. She was displaying behavior I hadn't seen before. In the photo, she is above the foreground squash leaves, to the left of the end of the cucumber vine and behind the long broad leaves of a flower. She was scurrying around with her beak to the ground. Insects? Seems unlikely. On my approach she did a short flight to the center of the garden, hopped another anti-bunny fence, and then I saw what she was after.

A twig! And not just any twig either. Look center in the rather bad Manet-like photo for the little over exposed Mrs. G. with a twig in her mouth. She found it suitable, took to her wings, and did an undulating flight over the roof of the house. By this point I knew I needed something besides the point and shoot camera, so I went into the house to get it. Glancing out the patio door, who should be there but Mrs. G. foraging for seed. Suddenly Mr. G runs straight at her, wings vibrating, doing yet another version of a finch courtship begging routine. No lost baby bird here. He's a yellow rocket jetting into her. In self defense she feeds him a seed which doesn't do much to allay his fervor as every time she moves he jets into her again. (Perhaps Mr. G. is young doesn't know what to do with all those hormones he's feeling? Perhaps he doesn't know he shouldn't bash his mate? Or maybe Goldfinch are wired to do this?) Whatever the answer Mrs. G. has had enough and takes off with speed. Mr. G. the golden rocket is right after her.
I'm theorizing that the creases under Mr. G's eyes, have nothing to do with lack of sleep, or being old. They have to do with being testosteroned to his eyeballs and it's wearing him out.
Donegal Browne

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