Flight burns less fuel than stopovers. (Zoology).The first measurements of energy use in migrating songbirds have confirmed a paradox predicted by some computer models of bird migration: Birds burn more energy during stopovers along the way than during their total flying time. Martin Wikelski of Princeton University Princeton University, at Princeton, N.J.; coeducational; chartered 1746, opened 1747, rechartered 1748, called the College of New Jersey until 1896. Schools and Research Facilities and his colleagues monitored 38 Swainson's and hermit hermit [Gr.,=desert], one who lives in solitude, especially from ascetic motives. Hermits are known in many cultures. Permanent solitude was common in ancient Christian asceticism; St. Anthony of Egypt and St. Simeon Stylites were noted hermits. thrushes during the nights of their spring migration through the northern United States The Northern United States is a large geographic region of the United States of America. Although the region includes a considerable portion of what is often called the American Midwest, most Americans refer to the region as simply "The North". . The researchers injected in·ject·ed adj. 1. Of or relating to a substance introduced into the body. 2. Of or relating to a blood vessel that is visibly distended with blood. injected 1. introduced by injection. 2. congested. the radio-tagged birds with chemical-isotope tracers Tracers Refers to investment trusts which are populated by corporate bonds. In October 2001, Morgan Stanley's Tradable Custodial Receipts (Tracers) was launched. Tracers contain a number of coporate bonds and credit default swaps which are selected for liquidity and diversity. that enabled the scientists to measure the birds' metabolism. The team members spent their nights driving a car, trying to keep up with a tagged bird. "We got stopped by a cop just about every night, not because we were speeding, but because they wanted to know what somebody was doing in a little town in Wisconsin at 4 a.m. with a giant antenna on the roof of a car," says Wikelski. A dozen birds took night flights covering up to 600 kilometers. The rest stayed put. The scientists determined that the birds that flew burned 71 kilojoules of energy on an average night's flight of 4.6 hours. The birds that didn't fly burned energy at 88 kJ per day. Since the birds spent about 24 days and nights on stopovers during a typical 42-day journey from Panama to Canada, actual flying consumed only 29 percent of the total energy budget for the migration, Wikelski and his coworkers report in the June 12 Nature.--S. M. |
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