Laura Erickson's For the Birds

(Recording of a Turkey)

Every now and then when I’m researching this program, I run into an item that interests me, even if it is completely unrelated to the topic of the day. For example, do you know why some birds have dark meat on their breast and wings, yet others have white meat? It’s the same principal as in running–runners who excel at short bursts of speed, like the hundred yard dash, have muscles that can work hard for a short time with very little oxygen. Mile runners may not run as fast, but their speed is sustained for a longer time and distance because their muscles can absorb a good deal of oxygen as they work. White meat is found on chickens, turkeys, grouse, and pheasants. These birds never fly long distances, and so their wing and breast muscles don’t require a rich and steady supply of blood. But if a goshawk or a human hunter approaches, they can burst into sudden flight to escape, taking advantage of anaerobic processes for a short time, the way a 100-yard dash runner does. If they’re flushed more than a couple of times, though, most of these gallinaceous birds won’t be able to take off again for quite a while, until their muscles recover. Because they spend most of their time walking, their leg muscles are oxygen rich, which translates into dark leg meat on the table.

Geese and ducks, on the other hand, are always walking or swimming, using their leg muscles, or flying long distances with sustained wing beats. So both their wing and leg muscles need a rich oxygen supply– explaining why goose and duck meat is always dark.

Another item: birds are seldom associated with vampires, but the Sharp-billed Ground-finch of the Galapagos Islands is a genuine blood- sucker. This little bird hops on the backs of oceanic birds called boobies and bites them on the rear part of the wing, beyond the reach of the booby’s bill. The finch then sucks blood up from the bite. Although no other bird is known to regularly feed on blood, I have heard a couple of accounts of Black-capped Chickadees lighting on cuts and scratches of people in the woods and nibbling at the dried blood.

Because they aren’t mammals, birds don’t need milk, although some pigeons make a whitish fluid in their digestive tract called pigeon milk. But in Britain, relatives of our chickadees called Great Tits pry open milk bottles on porches to drink the milk. This habit has now spread to the tits over much of Europe.

And how about this–everyone knows that birds require water to live, but two groups of oceanic birds, the shearwaters and petrels, can’t use freshwater at all–they die of thirst without salt water.

Most birds drink water by sipping a drop, tilting the head back, and letting it slide down the throat. Pigeons and doves and an African bird called the sandgrouse are the only birds able to suck up water without tilting their heads back.

One last item: woodcock, those little brown gamebirds with long, long bills, eat worms which they probe out of the soil. Now how can a bird dig three inches into the soil to get a worm? It would be hard to push away all that dirt to grasp the worm if the bird’s bill was closed to begin with, but if it was slightly open before going into the soil, the bird would end up with a mouthful of dirt. So the woodcock has a unique adaptation–a prehensile bill. The tip is flexible, and can be opened without opening the rest of the bill if a woodcock feels a worm deep in the soil.

(Recording of a Woodcock)

This is Laura Erickson, and all these useless facts have been “For the Birds.”