Taking the Long Way Home
Researchers have discovered that sooty shearwaters travel nearly 40,000 miles each year during migration
AND YOU THOUGHT your commute was tough: Researchers have discovered that sooty shearwaters, among the most abundant seabirds in the world, travel nearly 40,000 miles each year during migration. That’s the longest electronically documented migration of any animal. Last year, University of California–Santa Cruz research biologist Scott Shaffer led a study in which he and his colleagues attached tiny, ultralight electronic tags to the legs of 33 shearwaters at their New Zealand breeding grounds, then returned nearly 10 months later to retrieve the tags, which recorded extensive data but did not transmit it.
In the span of 200 days, the seabirds traveled east from New Zealand to coastal South America, then northwest to the North Pacific, where they split off for Japan, Alaska or California. Then, finally, they flew home to breed in the exact nesting burrows where they were first tagged.
The birds’ extraordinary migration could make them good indicators of climate change, says Shaffer. If water temperatures continue to rise, “their migration patterns could alter or we may see die-offs in response,” he says. In the 1990s, for example, researchers noticed a dramatic drop in sooty shearwater populations along California’s coast. The suspected cause: a declining food supply brought on by warmer waters.—Hannah Schardt