Wednesday, December 21, 2011

For Many Species, Moving Day Has Added Stress

Every fall the calliope hummingbird, which weighs about as much as a penny, braves high winds and bad weather to migrate from Canada and the northern United States to as far south as Mexico, then back again in the spring — a total of 4,000 to 5,000 miles. The journey is one of several dozen “spectacular migrations” — in the air and on land — that are chronicled in a new report by the Wildlife Conservation Society. But the report warns that these migrations are in peril. “Long-distance migrations as a whole are rapidly disappearing,” said an author of the report, Keith Aune, a senior conservation scientist here in Montana for the wildlife group, which is based at the Bronx Zoo in New York. The report surveyed wildlife biologists across the Western United States, where most of the large-scale migrations still take place. It details 24 terrestrial and 17 aerial migrations; a later report will take up ocean migrations. There are many more imperiled migrations, Mr. Aune said, but these are both the most important and the most likely to survive if they receive public support. Long-distance migrations are not only a spectacle, he said; they are crucial to keeping wildlife species extant in a changing world. “They are about survival,” he continued. “When we block migrations, we lose the ability to sustain a population.”...more

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