Flying great distances, and spreading a disease
Ornitholologists have long known that waterfowl migrate huge distances. But it is rarely possible to be sure where any flock’s route begins and ends—information useful to tracking the spread of avian flu. The Wildlife Conservation Society, which runs New York City’s zoos, has found proof that bar-headed geese—one suspect in moving the flu around the world—can travel 3,000 miles from their breeding grounds. Last summer, the conservation society caught 50 wild geese there. Scientists wrapped them in brown canvas “swan jackets” to keep them still, then took blood samples, oral and cloacal swabs, and feather and toenail clippings (isotopes in the last two may reveal, though imprecisely, where they summered). Then the birds, including one designated E6, were banded. “In December,” said Dr. Martin Gilbert, a field veterinarian, “we got an e-mail from a chap in southern India who’d been photographing geese at a local lake. He didn’t even see it in the field, but in his pictures, he noticed that one had a yellow neck collar. It was E6.” Whooper swans tagged at the same time, Gilbert said, went east to China’s Yellow River. In the past year, avian flu has been found in chickens north of the area where E6 landed. But it is impossible to know how it arrived, since the disease is also spread by poultry transport.

Getting rid of vermin might not be beneficial
If every rat, cockroach and bedbug disappeared from New York City, would that be a good thing, ecologically speaking? “We would avoid the diseases, bites and frightful moments that they bring to our lives,” said Steven N. Handel, professor of ecology and evolution at Rutgers University, but problems might result from the emergence of other species to fill their niches in cleaning up human leftovers. Like many of New York City’s people and weeds, many of its pests came from other continents, including bedbugs, cockroaches and European rats. In fact, Handel said, concentrations of people “are the ground zero of the pest explosion,” providing both warm shelter and garbage to feed upon. Handel said that the disappearance of bedbugs would probably leave no serious bad consequences but that eliminating some of the other vermin might mean “simply exchanging one suite of kitchen crashers for another, albeit smaller and less visually frightening.” Microbes are everywhere and carry their own public health problems, he continued. “If it’s goodbye cockroaches, then it’s hello fungi,” Handel suggested. “We will never be alone.”

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