Wednesday, March 19, 2014

Feathers: Form Fits Function

Last week, I wrote about how to improve the lives of your pets through enrichment. I showed examples with the animals where I work, but I never introduced you to my own pets! I have two pets, a male and female cockatiel.

This is Peanut, my little man:

And Tucker, my "lemon chicken" girl:

Right now, Tucker is in what I call a "super molt," something she goes through about twice a year. In the wild, birds replace their feathers twice a year: once in the spring, and again in the fall. This not only keeps them looking fresh and sexy for the ladies (or gents in the case of polyandrous birds), but also ensures that their feathers are in tip-top shape for flying. Birds in captivity, like wild birds, will lose and occasional feather here and there, but also go through periods where they molt large amounts of feathers at a time. During Tucker's super molts, she can sit preening (cleaning her feathers) for 30 seconds on the couch and this happens:
My house becomes littered with feathers, rolling across the floor like little tumblefluffs. But no matter how many super molts I've been through, I never get tired of seeing all the different shapes and forms Tucker's feathers come in. Birds' feathers are an amazing testament to form fits function, with each feather uniquely sculpted to fit a specific purpose.

Peanut wanted to contribute to this post too, so his feather is showcased at the left. Remiges are the flight feathers on the wings; the classic quill feather. These feathers are stiff and strong and are inserted directly into bone instead of skin like most feathers, and so are able to push hard against the air in order to achieve flight. In actuality, all a bird's feathers have a role in flight, but if a bird loses too many remiges, it will be rendered flightless. The narrow side of the central shaft is the leading edge of the wing. Because of this, we can tell this feather came from Peanut's left wing. 

Not as stiff as remiges, retricies are a bird's tail feathers and are also inserted straight into bone, in this case the last tailbone called the pygostyle. These feathers are responsible for steering in flight. A bird also steers with its wings, true, but holding its wings perfectly still, a bird can make a slightest twitch of its tail to turn. They can also spread their tail feathers to slow their flight, or tuck them in nice and neat when performing a swift dive. The feather on the left is one of Tucker's central tail feathers, as can be told by its perfect symmetry. Feathers from the left or right side of her tail look slightly different, like the beautifully patterned one on the right. Using the same guidelines as with the remiges, can you tell which side of the tail this feather came from?

No covert operation here, just feathers whose job are to protect the flight feathers on the wings and tail. This feather is one of my favorite of Tucker's, a tail covert, aka "buttvert." Just look at the cup to fit her little feathered butt, people. And it's so fluffy I'M GONNA DIE. Nobody likes a cold rear end, and birds are no exception. All that fluff at the base of both the retrices and their coverts makes for a nice, warm, fluffy behind.

Contour Feathers
The majority of feathers you see on a bird are contour feathers, whose function is to not only keep the bird warm, but to give it its aerodynamic shape. The colors of the contour feathers also perform roles in attracting the opposite sex and camouflage. Most contour feathers have a slight curve, lending their shape to the overall curve of the bird. But look at the contour feather on the right. This feather is thin, perfectly flat, and almost rectangular. It's a wingpit feather! This feather is perfectly shaped to fit tightly up against Tucker's body beneath her wings. The last thing you'd want as a bird (besides a cold butt) is feathers that get in the way of your wingbeats. These feathers perfectly fit that need, protecting her body, while not getting in the way.

Other specialized feathers
There are all sorts of other little specialized feathers to be found on a bird's body, like tiny filoplumes...
which can be found at the base of almost every contour feather and are sensitive to air movement and vibrations. This allows a bird to feel the place of every feather on their body, and know when one is the slightest bit out of place and needs attention.

There's bristles:
which look like tiny whiskers between Tucker's eyes and beak but are special feathers stripped down to their central barb. Bristles like Tucker's help keep dirt, insects, and other foreign things out of her eyes and nostrils. Bristles on some birds, like nighthawks, help them to sense when insects are near their mouths when feeding. And on birds of prey and vultures, bristles mixed in with the contour feathers can help keep blood and gore off of the contour feathers.

And finally since we're talking about cockatiels, we have to mention the fabulous crest feathers:

For some feathers, their form is their function. That is to say that some feathers are fabulously shaped for the sake of being fabulous. For a cockatiel's crest, not only can they attract attention, but they are incredibly expressive, like little birdy eyebrows. You can even literally see Tucker thinking, as her crest goes up and down as she's really puzzling over how to steal food off of my plate. However, crest feathers are probably the most awkward thing to happen as they loosen during a super molt.
Poor, poor, unicorn Peanut.

Tucker's super molt is slowing down, meaning there are less feathers being dispersed all over my house. But whenever I pick one up, I can look at its shape and tell exactly where on Tucker's body the feather came from, thanks to nature's excellent design of form fitting function. 

1 comment:

  1. With the feathers everywhere, you don't have dust bunnies; you have dust birdies! Thanks for the education, now whenever I come across a feather while hiking, I'll try to puzzle out it's original location. Thanks!