Little Green Eggs

A wave slaps the Delaware Bay shore and an American horseshoe crab tumbles out of the surf. It's early May.

The crab claws its way in a slow, clumsy advance over a mudflat, jerking along like a toy Army tank with a cranky spring-wound motor.

One by one the crabs leave the sea for beaches on both sides of the bay until millions of these olive drab creatures blot mud and sand. It is one of the oldest journeys on earth, older than dinosaurs, and it is an important one. For it is on the bay's beaches that the horseshoe crabs breed, propagating a species that dates back 350 million years.

At water's edge males court females, attaching themselves to the rear of the female's carapace (or shell) with pincer-like appendages. Then the females tow their suitors up the beach, scratch out hollows in the sand, and lay tiny pea green eggs which are fertilized by the males. But the waves at high tide wash away much of the sand and soon billions of the eggs lay exposed on the beaches.

Thousands of miles away another biological clock is ticking. Red knots, ruddy turnstones, sanderlings,
and semi-palmated sandpipers are already in flight, leaving behind their wintering grounds in Central and South America -- the mudflats of Surinam, the rocky nooks at Tierra del Fuego, the meadows on the Argentine Pampas.

They're winging some 7,000 miles towards the bay and the little green eggs which are now crucial to their survival. Depleted of fat reserves on arrival, many birds will almost double their body weight during their two-week stopover before departing on the next leg of their journey -- a 2,000-mile, non-stop flight to their Arctic breeding grounds. By late June, the shorebirds will be nesting on the thawing tundra.

The Delaware Bay is the principal breeding grounds for American horseshoe crabs on the East Coast and among the largest staging areas for shorebirds in North America. And it is unique in that there's only one main course on the menu: the little green eggs. Destroy the horseshoe crab's habitat and a vital link in the migratory chain would be broken, and thousands, perhaps millions, of shorebirds endangered.

Download Little Green Eggs Flyer
(224 KB; free Adobe reader required)

PBS NATURE: "Crash: A Tale of Two Species"
(Originally Aired on PBS February 10, 2008)

Learn more about this fascinating story by listening to
Van Williamson's report, "Birds and Crabs,"
broadcast on National Public Radio's Morning Edition, June 11, 2002.
(free audio player required)

LINKS:

Governor Corzine Signs Moratorium on Harvesting Horseshoe Crabs in New Jersey (3/25/08)

Delaware Department of Natural Resources and Environmental Control (DNREC) News Release:
New Horseshoe Crab Regulations Set Harvest Cap, Season (10/18/2007)

New Jersey Division of Fish & Wildlife Delaware Bay Shorebirds

Delaware Division of Fish & Wildlife Shorebird Project

Horseshoe Crab History, Biology, Research, and Conservation
(This site is a joint effort of the Mid-Atlantic Sea Grant Programs and the National Oceanic and Atmospheric Administration)

The Humble Horseshoe Crab

The Horseshoe Crab - Natural History, Anatomy, Conservation and Current Research

U.S. Geological Survey's Horseshoe Crab Monitoring Site

Discover Delaware Bay Shorebirds

U.S. Fish and Wildlife Service's "Shorebirds: Winging Between Hemispheres"

Shorebird Sister Schools Program - Atlantic Flyway
(A U.S. Fish and Wildlife Service program
linking schools, biologists & shorebird enthusiasts along flyways)

Chipper Woods Bird Observatory's "The Importance of Migratory Stopovers"

Virtual Birder

The Horseshoe Crab -- Putting Science to Work to Help "Man's Best Friend"
(University of Delaware's Sea Grant College Program)

Delaware Estuary's "Horseshoe Crab and Shorebirds" Fact Sheet
(free Adobe reader required to download this 441 KB file)

Delaware Audubon Society's "Horseshoe Crabs Given Sanctuary
by National Marine Fisheries Service"

New Jersey Audubon Society's Cape May Bird Observatory

Atlantic States Marine Fisheries Commission

 

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