Some seabirds don’t just survive storms. They ride them.
Japan’s islands are home to a variety of endangered shearwaters. Sometimes you head straight towards passing typhoonsResearchers report in the Oct. 11, that the birds fly for hours close to the storm’s center, and they are able to land safely. Proceedings of the National Academy of Sciences. This strange behavior — not reported in any other bird species — might help streaked shearwaters (Calonectris leucomelas) survive strong storms.
Birds and other animals that live in areas where hurricanes and typhoons are common have adopted this approach. These deadly storms can be avoided by using strategies (SN: 10/2/15). In recent years, a few studies using GPS trackers have revealed that some ocean-dwelling birds — such as the frigatebird (Fregata minor) — will take To avoid cyclones, make huge detours.
This is an understandable strategy for birds that spend most of their time at sea where “there is literally nowhere to hide,” says Emily Shepard, a behavior ecologist at Swansea University in Wales. Shearwaters can also avoid storms. Her colleagues used 11 years worth of data collected from GPS locators attached on the wings of 75 birds nesting at Awashima Island, Japan.
Combining this information with data about wind speeds during typhoons, researchers discovered that shearwaters who were exposed to the open ocean while a storm was blowing in would ride tailwinds along the storm’s edges. Some people would fly differently if they were trapped between the storm’s eye and the ground.
Of the 75 monitored shearwaters, 13 flew to within 60 kilometers of the eye — an area Shepherd calls the “eye socket,” where the winds were strongest — for up to eight hours, tracking the cyclone as it headed northward. “It was one of those moments where we couldn’t believe what we were seeing,” Shepard says. “We had a few predictions for how they might behave, but this was not one of them.”
Shearwaters were more likely than other birds to follow the eye in stronger storms. They could fly at speeds of up to 75 kilometers an hour and so they flew towards the eye. Shepard believes that this suggests that the birds are following the eye to avoid being blown inshore, where they could be hit by flying debris or crash onto the ground.
This behavior is not common in birds, but it has been observed for the first time in any species. Andrew Farnsworth, Cornell University’s ornithologist, said that flying with the wind could be a common way to conserve energy during cyclones. “It might seem counterintuitive,” he says. “But from the perspective of bird behavior, it makes a lot of sense.”
