[My last South Carolina post, I think.]
Talk about airmiles. The Red Knot, Calidris canutus rufa , a sandpiper, enjoys the reputation of undertaking one of the longest migrations in the natural world, a round-trip as long as 19,000 miles. They breed in the high Arctic, but they over-winter all along the coasts of the Americas, as far south as Patagonia. This map shows their range in the Americas:
They weight in at under 5oz, yet they can fly 5000 miles without touching the ground.
In South Carolina, there is a population that over-winters there, but it is also a stop-over point for birds who have come from much further south and are on their way to their Arctic honeymoon hotels. The numbers are huge:
These are on a low-lying unoccupied sandbar island, now protected from humans during migration and nesting season, called Deveaux Bank. All the photos are taken from a boat offshore, which was bobbing around, so they are a little quavery! It is serenely beautiful:
What, for the Red Knots, makes it “vaut le détour”, as the Guide Michelin would say, is the presence of vast numbers of prehistoric horseshoe crabs mating and laying small green eggs.
The eggs are a rich and very digestible food source to support these birds on their long migration, but the horseshoe crabs were over-fished, both because they make good bait for fishermen, and because scientists use their blue blood (yes, really, see below for more*) to test for bacterial contamination. Probably as a result, Red Knot numbers dropped sharply in the 2000’s, and in 2014 this subspecies was listed as threatened by the US Endangered Species Act.
Once they reach breeding season, their plumage acquires a reddish color, as you can see in the image below from the All About Birds website:
but at the moment they are grayish buff. In flight, the birds have a white line running the length of their wings , like the center bird in the photo below (The larger reddish bird with a long bill is a Marbled Godwit. )
Deveaux Bank is crammed with birds, including a colony of Brown Pelicans
On our return boat journey to Wadmalaw Island, we saw a Long-billed Curlew, apparently the first seen around here in some time, with an oystercatcher curled up beneath his feet:
A magical day off the shore of this ever-changing sandbank island.
P.S. I am very grateful to Dana Beach, who took me to Deveaux, and who was instrumental through the Coastal Conservation League in getting it protected in 2015. Here is some more information:
*For more about the scientific use of horseshoe crab blood, read this: