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Red Knot - June 2003 Species of the Month

NOTE: Content on this page has not been updated since October 2004; please see Red Knot - An Imperiled Migratory Shorebird in New Jersey for the latest information on this species.

The Red Knot (Calidris canutus) was the June Species of the Month in honor of the 30th Anniversary of the New Jersey Endangered Species Conservation Act and the formation of DEP's Endangered and Nongame Species Program (ENSP).

Survival of the migratory red knot depends on the horseshoe crab. Every year in May, the horseshoe crab lays its eggs along New Jersey's southern and central beaches. En route from the southern tip of South America to their breeding grounds in the Canadian Arctic, red knots stop on the beaches of the Delaware Bay to gorge on the fat-rich crab eggs.

Studies show a significant decline in the spawning horseshoe-crab population during the past decade and consequently, a lower concentration of crab eggs, leaving many migrating shorebirds without enough to eat. Unable to gain sufficient weight during their Delaware Bay stop over, many shorebirds lack the energy to complete their Arctic migration and to reproduce. Most in peril is the red knot, listed as a threatened species in New Jersey in 1999. Scientists predict it could be extinct within seven years.

Red knots in surf
Red knots in Delaware Bay surf
© Clay Walker

This spring, both New Jersey and Delaware took significant steps to protect the red knot population from further decline. Both states imposed restrictions on horseshoe crab harvest and on public access to Delaware Bay beaches to allow shorebirds to feed undisturbed.

Every year since 1999, DEP staff leads a team of experts from the United States, Canada, Argentina and Chile to study the red knot's various habits and habitats along its migratory path.

Gaining Weight for the Trip

There is a dramatic difference in appearance from when a red knot arrives on the Delaware Bayshore and when it is ready to depart for the Arctic.

Knot upon arrival
Red knot upon arrival

Knot ready to depart
Red knot ready to depart

The Red Knot – Traveling on the Edge

  • The beaches in Delaware Bay are essential spawning habitat for the world's largest concentration of horseshoe crabs. In turn, these beaches attract the Western Hemisphere's second-largest spring migration of shorebirds, which feed on the crab eggs. Over a million shorebirds representing six different species including red knots, feed on the eggs in May and early June.

  • Major declines in the spawning horseshoe crab population since the early 1990s and a lower concentration of crab eggs are attributed to an increase in the numbers of crabs being harvested to satisfy the growing public demand for conch and eels, trapped by using horseshoe crabs as bait.

  • The red knot is hardest hit by this decline because about 90percent of its population in the Western Hemisphere "refuels" on Delaware Bay each spring. DEP biologists have discovered a decline in red knots on Delaware Bay, from 95,000 in 1989 to fewer than 32,000 in 2002. A decline of more than 50 also was observerd at its South American wintering area. The count for May 2003 was the lowest ever at just 16,000 knots.

  • Red knots arrive in Delaware Bay from South America thin and tired, many of them having flown non-stop for four days. They must quickly double their weight to make the long flight to the Canadian Arctic and to breed once they arrive there. High energy crab eggs are essential. However, many red knots are not reaching the threshold weight necessary to make the trip and to breed. Additional conservation measures are needed to improve numbers of horseshoe crabs and create refuges where knots and other shorebirds can feed undisturbed.

Facts of Interest about the Red Knot

  • Must gain a minimum of 6 grams of weight per day while in Delaware Bay, to complete its journey to the Arctic and to breed. Red knots gained weight at the rate of 8 grams per day in 1997; now they only gain at the rate of 2 grams per day.

  • Size of a dove with a distinctive breast of rusty red during the summer breeding season; has a short, straight black bill and long wings.

  • Usually seen in Delaware Bay on sandy beaches with gentle slopes and minimal wave action; often roost on long sandy spits at ocean inlets, marsh islands, or the high portions of sandy beaches

  • In the Arctic, establishes nests in vast areas of sparsely vegetated, low elevation tundra; and in wintering areas they are found primarily on large tidal flats

  • The red knot is recognized as a high priority species in the National Shorebird Conservation Plan, is on the Audubon Watch List, and is a U.S. Fish and Wildlife Service species of conservation significance.

Knot on nest
Red knot on Arctic nest

Biologists with knot chick
Biologists Amanda Dey and Larry Niles band knot chicks in the Arctic

Ways You Can Help
Shorebirds feeding
Shorebirds on Delaware Bay

Don't walk on the beach during spring when shorebirds are present, and keep dogs on a leash. Use designated viewing areas for watching shorebirds, and study them from a distance with binoculars or a spotting scope. To learn more about suggested shorebird viewing areas, review the map in the following brochure: Imperiled Shorebirds on the Delaware Bay - What You Can Do to Help. (pdf, 423kb)

While many Delaware Bay beaches and some Atlantic coastal beaches are known to support horseshoe crab spawning from year to year, the DEP's Division of Fish and Wildlife is asking citizens to share their information and observations of current spawning sites. To learn more about observing horseshoe crab spawning and how to report such information, please read the following article on the DEP's Division of Fish and Wildlife Web site: Help Identify Horseshoe Crab Spawning Habitat.

Conserve Wildlife license plate Order a Conserve Wildlife special interest license plate for your vehicle. It's tax-deductible, with 80 percent of the payment benefiting New Jersey's Endangered and Nongame Species Program.

Want to volunteer? Enjoy giving presentations? Looking for speakers? The Division of Fish and Wildlife offers two opportunities:The Endangered and Nongame Species Program's Speakers Bureau and the Division's Wildlife Conservation Corps. Visit these sites for details.

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Additional Sources of Information

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Department of Environmental Protection
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Last Updated: November 21, 2007