Red Knot Continues to Decline

Red knots have continued to decline this spring. Migration counts along the Delaware Bay found only 12,300 knots, compared to 15,000 last year. Two decades ago, the population was much higher, in the hundreds of thousands.

A Red Knot Flaps Its Wings / Photo by Tim_Shaffer (Reuters)

Red knots are one of several species that migrate prodigious distances every spring and fall. Knots breed in the Arctic and spend the winter in southern Argentina and Chile. Their 9,000 mile migration requires that they have adequate food supplies along the way. A key stop during spring migration is the Delaware Bay, where hungry shorebirds regain their weight by feasting on the eggs of horseshoe crabs, which come ashore to lay their eggs just as the knots arrive. Over the last two decades, the number of horseshoe crabs has declined due to harvesting. Knots have declined along with the crabs.

States around the Delaware Bay recently imposed moratoriums and other restrictions on harvesting horseshoe crabs. The good news is that these policies appear to be working to some extent; captured shorebirds this year were at a healthy weight. Unfortunately, it will take several years for the horseshoe crab population to rebound enough for the red knot population to increase. Whether the red knots can last that long is an open question.

Because red knots have declined so rapidly, scientists and conservation groups have sought to have red knots protected under the Endangered Species Act. As with other declining species over the past six years, petitions filed with the US Fish and Wildlife Service so far have been ignored or denied. Federal listing would be helpful since it could then coordinate conservation actions among the various states whose policies affect red knots' survival as a species. Not all states are equally committed to protecting red knots; for example, Virginia turned down a horseshoe crab harvest moratorium, and Delaware was slow to impose one.

I have been lucky enough to see red knots in Delaware, though I missed them this year.

You can read more about monitoring red knots at The Shore Bird Project.

(news link via squeaks)

Update: Next week (June 11-14) there will be an International Symposium on the Science and Conservation of Horseshoe Crabs held on Long Island. (Thanks, Julie!)