University of Delaware
delware environmental institute

News Journal: Red knots proposed for threatened listing

The U.S. Fish & Wildlife Service is recommending threatened species status for the red knot, the robin-sized shorebird that passes through Delaware Bay each May. While the bird population has stabilized since it lowest levels in 2000, federal officials say new threats such as climate change, loss of coastal habitats and shorebird hunting in the Caribbean and northern South America have placed the species at risk of future extinction.

“The largest threat to the red knots ... is global and that is this threat of a changing climate system because it is climate change, especially acting on this already vulnerable species, that is a looming threat driving sea level rise and alterations in habitat, driving changes in water temperature that are changing some of the availability of food resources and the timing of those resources,” said U.S. Fish and Wildlife Service Director Dan Ashe.

The birds are hard-wired to migrate at specific times and there is a concern that the migration could become out of sync with food resources. The primary food for red knots in Delaware Bay, for instance, is the horseshoe crab egg. Crab spawning is triggered by water temperatures in the bay.

Delaware Bay is considered the epicenter of the spring horseshoe crab spawn and the migration of red knots and a half-dozen other key shorebird species. Red Knots feed on horseshoe crab eggs while in the bay and federal officials believe the bird population decline is directly linked to overharvesting of the crabs used as bait.