For the Birds Radio Program: Bird Gluttons: Original
(Recording of a Turkey)
There are probably one or two Northlanders sitting out there who can’t believe they ate the whole thing yesterday. But even the most gluttonous person can’t compare to a bird when it comes to how much food he can pack away. Bird gluttony is not a pretty subject–if you are in the middle of your breakfast, you may want to close your ears for the next few minutes. When you think of a sweet little black-and-white warbler, do you really want to know that it can eat 80% of its weight in grasshoppers every day? Or that captive woodcocks have eaten their total weight in earthworms in a single day?
Birds have a much faster metabolic rate than mammals. The body temperature of sparrows is about 107 degrees, and some thrushes have a temperature as high as 113 degrees. Even an ostrich has a temperature of 104 degrees. It takes a lot of fuel to maintain that kind of metabolism. A growing bird’s digestive system extracts about 33% of its food intake as usable calories–compared to only about 10% in a growing mammal. Even with that high efficiency, birds eat a tremendous amount relative to their size.
A pair of loons with their chicks will consume well over a ton of fish during the fifteen weeks it takes to raise the young. An eight pound brown pelican eats 4 pounds of fish daily. The black-footed albatross is often called a “feathered pig” because if can swallow half- pound chunks of fresh shark meat in one gulp. Turkeys eat as much as a pound of nuts or acorns in a single meal. Robins eat as much as 14 feet of earthworms every day. And an owl sometimes swallows so many mice or rats that its crop can’t hold them all–the tail of the last one may hang out of the mouth until some of the first have been digested–not a pretty sight, even on the radio. Of course, for every night hunting is that good, there are dozens of nights when little or no food at all is taken–that’s why you never see a fat owl.
There are stories of California Condors and turkey vultures eating so much that they couldn’t take flight. One cormorant in California died after a 10-inch fish got stuck in its throat. Right here in Duluth, observers have seen robins and Cedar Waxwings drop dead after pigging out on apple blossoms or mountain ash berries.
Birds that hunt or fish for a living often take on prey that they would have been better off avoiding. One golden eagle died after taking on a porcupine. There’s a preserved hawk in a display case outside UMD’s biology department that met the same fate. A red-tailed hawk in South Dakota carried off a weasel, but in mid-air the weasel got a death grip on the hawk’s throat. Six young common terns died on Long Island in 1962 after swallowing blowfish. And more than one osprey has drowned trying to pull a heavy fish out of the water.
All in all, it makes the biggest Thanksgiving pig-out look like pretty mild stuff.
(Recording of a Turkey)
This is Laura Erickson, and this program has been “For the Birds.”