Migrating birds have learned to adjust their sleep habits to make for a more efficient trip down south.
Welcome to this week’s edition of Something Wild. I’m Rosemary Conroy for the Society for the Protection of New Hampshire Forests.
In a recent spot, I spoke about where birds sleep in winter. I guess the next question is where - or, rather, do - birds sleep the rest of the year?
It sounds like a strange question, but scientists have uncovered evidence that during migration, anyhow, many songbirds hardly sleep at all. As you know, many of them fly the long distances between their wintering and breeding grounds primarily at night. That's because the cool night air is less turbulent and the birds can cover more distance with much less effort. So what about during the day? Well, that's when our hearty migrants must forage to regain all the body fat they used up flying the night before.
In order to get themselves off the ground, birds really can't pack on too much weight. So they have evolved a super-efficient metabolism that lets them pack on fat and them burn it up quickly.
Apparently their resourcefulness extends to time management as well, as in "Who has time for sleep"?
Scientists used to think that perhaps migrating song birds flew with one eye open and one eye closed. Strange as that may sound, many species can sleep with half their brain at a time. Mallards, for example, have been shown to do this. It's a great way to catch some Z's while making sure you don't get caught by a hungry predator. Apparently dolphins, manatees and seals can use this half-awake, half-asleep trick too.
But not migrating songbirds. Studies have shown that species like thruses and sparrows sleep 63 percent less during their bianuual travels. And they do it without getting sick or appearing to be impaired in any way! Scientists are quite puzzled by this enviable behavior, and plan to study the phenomenon more closely. Day and night, in fact - if they can pull it off!
Something Wild is a joint production of the Society for the Protection of New Hampshire Forests, New Hampshire Audubon, and New Hampshire Public Radio.
For Something Wild, I’m Rosemary Conroy.
