Looking for red knots on the shores of Delaware Bay
Last week, as part of my internship with the Service and SCA, I found myself crouching behind dunes, waiting for biologists to trigger a cannon net in order to capture and band red knots and other shorebirds.
We were in Cape May, New Jersey — on the Delaware Bay side — to document recently restored beaches that had been devastated by storm surge from Hurricane Sandy. The biologists we were tailing hailed from such distant locales as Canada, England and Brazil — all assembled in southern New Jersey to study the biannual migration of red knots. Though, no one on the beach had come farther than the birds themselves.
As you may have known from our coverage of the shorebird, red knots have been proposed to list as a threatened species–the first bird, in fact, to be proposed to list under the Endangered Species Act primarily to the threat of climate change. The team of biologists were there to take measurements to determine how the Delaware Bay population of red knots is doing.
We were hunkered down behind some beachgrass for about forty minutes. One of the biologists from England joked about how, one time, they had waited five hours for the birds to make their way into the cannon net’s range. The same biologist had his thumb on the ominously-named “Firing Box,” which looked like an old Gameboy(tm), but was attached by around 100 yards of wire to the three metal tubes buried in the shoreline, loaded with a specially designed net to trap these world-traveling shorebirds.
Red knots sometimes migrate from as far away as Tierra del Fuego in Argentina, moving as far north as the Arctic. One high-profile red knot earned the nickname “Moonbird” because over the course of its lifetime, researchers found it has gone more than the distance from the earth to the moon and over halfway back. The species times its migrations to stopover in Delaware Bay precisely, to arrive right when horseshoe crabs spawn. By eating horseshoe crab eggs, red knots can build up the fat reserves they need to continue on to the Arctic. Unfortunately, red knot populations haven’t done well, as development has eaten up their shoreline habitat, and rising ocean temperatures are thought to be changing the time of horseshoe crab spawning, among a number of other threats, including the overharvest of horseshoe crab eggs.
Forty minutes pass, glacially. The flecks of rain never resolve into a drizzle, but remain sharp and sudden. As the flock of shorebirds pick their way down the beach, keeping still and quiet was made all the more impossible by the legions of gnats that set upon us.
Then, the cannon goes off. After the biologists rush to free sanderlings and other common shorebirds and carefully bag the red knots, we ended up studying, banding and releasing more than a dozen of these rare birds.
To see such a fragile and complex system at work—of the million-year old cycle of red knots timing their stop just in time for horseshoe crab spawning—proved inspiring and momentous. But one thing remained clear: restoring these important beaches seems to be working. When the beach is restored, it not only protects human communities near the shore, but it replenishes the habitat that endangered and rare species need to survive, and can sometimes be that critical difference before they’re lost forever.