Science

The Bomb Cyclone Forced Hundreds of Killdeers to Bermuda

The birds typically stay on the U.S. mainland all winter, but this month's extreme weather resulted in an influx of visitors to the island.

Earlier this month, Andrew Dobson, president of the Bermuda Audubon Society, went to check on some reports of stray American Pipits seen along the island's coast. But as he got in his car, he heard the familiar calls of another irregular migrant—Killdeers. While the birds are fairly uncommon visitors to Bermuda, it wasn’t a total surprise to hear them; in 2017, their Christmas Bird Count tally numbered 12. Dobson made note of the sounds and continued on his way. 

When he got to where the pipits were reportedly located, though, he made a shocking discovery while scanning for the birds from his car—around 100 Killdeers flying along the coast. A hundred more lounged on the beach. Over at the airport, he found at least 500 Killdeers were sitting on the grass. Everywhere he looked, more Killdeers. All in all, Dobson estimates that more than 1000 birds had made their way the roughly 700 miles across the Atlantic from the East Coast.

“It has been quite an event,” Dobson says. “This is perhaps the greatest number we’ve ever had.” In the past, the record number of Killdeers reported was around 100.

Although the numbers are unusual, why the birds showed up in Bermuda is easily explained by their migration tendencies. These medium-size plovers are what's called facultative migrants, meaning they can be somewhat flexible as to when and how they travel. Many Killdeers living in the U.S. are only short-distance migrants, but this winter, for groups of Killdeers trying to escape the particularly frigid temperatures and extreme weather along the East Coast earlier this month, they had to keep moving.  

“It's a combination of having the bomb cyclone move through just after this period of really extreme cold,” says Kenn Kaufman, a renowned bird expert and field editor for Audubon. “[Birds are] not just moving south, they're moving to coastal areas where things might be a little bit milder.” Once the Killdeers reached the coast, however, some apparently kept going out over the water. Caught up in the wind circulation of the bomb cyclone, they kept flying downwind until they reached Bermuda. 

As facultative migrants, Killdeer are flexible in when and how the move. Seeking escape from this month's inclement weather, an estimated thousand birds ended up in Bermuda. Photo: Andrew Dobson

“Killdeers are among those birds that set up on wintering grounds but then keep the ability to move again southwards if conditions get really bad,” Kaufman says. Their arrival on Bermuda was “just an accident” as the birds winged away from the freezing temperatures plaguing the U.S. (The storm also pushed at least a dozen Killdeers north to Newfoundland for the first January records since 2011, when another major storm scattered the birds.) 

Killdeers were not alone in finding Bermuda a refuge from the storm. Dobson says that he and other volunteers found the American Pipits he was originally looking for, as well as a Great Black-backed Gull, several Western Sandpipers, a Long-billed Dowitcher, and, remarkably, a Northern Fulmar found eagerly feeding on a fisherman’s chum. Dobson says most of the birds seemed exhausted and were happily recovering from their long journey.

So far, Dobson reports that the Killdeers are still hanging out in Bermuda. Kaufman speculates that they will probably extend their vacation for another two or three months, although it’s hard to know for sure. “I think by far the most likely scenario is that most of them will hang around until early spring and then at least make the attempt to fly back to the mainland,” he wrote in an email. “Chances are good that at least some will succeed in getting back to their breeding territories in North America.”

Until then, they’ll just have to continue enjoying the warm weather and sunshine they discovered on their surprise journey south. Sounds terrible, right? 

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