Monday, February 23, 2009

Mystery Shorebird: Knot or Not?


While spending a morning last week on the beach on Sanibel Island, Florida, I was seeing the usual shorebird suspects: willets, sanderlings, and a few ruddy turnstones. Then a flock of chunky birds dropped in, settling among a resting mixed flock of terns and gulls. My first pre-bins guess was dunlin, but when I got them in my binocs I noticed that they were bigger than dunlin, plumper looking, and lacked the dunlin's longer decurved bills. They settled down and immediately tucked their bills under their wings to rest. Could they be tired migrants?


These birds were in drab winter plumage, with uniformly gray-brown backs. They had a medium-length bill. A fair amount of scalloping was on the breast and flanks and the legs were dull yellow and relatively short. There was the hint of an eyebrow and a darkish cap.


This was adding up to be a pretty neat species. Finally the snoozing birds raised their heads and and I felt solid in identifying them as red knots. This is one of our most imperiled shorebird species. Red knots winter along the southern coasts of the U.S. We almost never see this species in Ohio.

I've seen red knots many times before—usually along the Delaware Bay where they stop in spring migration to feast on the bountiful eggs of horseshoe crabs. Nature in its infinite wisdom and perfect timing, aligned the nesting of horseshoe crabs, which come to shore to deposit their eggs by the millions in spring, with the passage of migrant shorebirds—especially the red knot. The knots fatten up on the tiny green eggs and put on fat necessary to fuel their remaining journey to the northernmost sliver of the North American continent to nest.

The fishing industry in the East has been over-harvesting horseshoe crabs to use as bait. The resulting reduction in nesting horseshoe crabs has drastically reduced the primary migration food source for the red knot. And this has affected the red knot population, which has dropped more than 50 percent since the 1980s.

It was a privilege to see this small flock of red knots, as yet unbanded, spending the winter here on this beautiful beach. I wished them well in their season of travel to come.

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