Special features

Horseshoe crab eggs and Red Knots and other shorebirds in Delaware Bay, New Jersey

New Jersey's Delaware Bayshore offers a feast for shorebirds
By Arthur Morris | Published: 5/1/1994

Photo by Mike Parr/ABC

Photo by Mike Parr/ABC

I had lain motionless under the decrepit wooden steps for more than an hour — hoping that one of several small groups of foraging Sanderlings and turnstones would move into shooting range. Unexpectedly, a huge flock of Red Knots landed right in front of me. They were so close that photographing them with my 400mm lens was out of the question — where was my 50mm lens when I needed it?

Suddenly startled, the eight thousand knots — scant yards away — crouched in fear, then leaped into the air, a swirling mass of silver, black, white, and varying shades of red orange. From my hiding place under the broken-down stairway to the beach (my makeshift photography blind), I watched the flock wheel, turn, and disappear to the west.

Glancing to the east, I saw a tiny old woman walking slowly in my direction, staring at me as if she couldn’t believe her eyes. It was her tightly leashed terrier that had flushed the shorebirds. With deliberate footsteps she continued her approach until she stood next to what had once been the bottom step. I looked straight up into her grandmotherly face as she squinted down at me. In a voice that cracked with age, she asked sweetly, “Are you all right, sonny?”

It was late May 1985, when I made my first visit to Villas, Cape May County, New Jersey. I crossed the dune at the west end of town precisely at high tide. I had been assured that thousands of Ruddy Turnstones, Sanderlings, and Red Knots would be gathered on the 15-yard-wide beach to dine on the eggs of the horseshoe crab(Limulus polyphemus). But stare as I might, I could discern only an empty gravel beach before me.

Abruptly, without warning or apparent cause, the entire “beach” lifted off and took flight. A vast cloud of sixty thousand Ruddy Turnstones, thirty thousand Sanderlings, and ten thousand Red Knots swept out briefly over Delaware Bay, then quickly resettled, again darkening the beach.

On another occasion, I had eased my car next to one of the two sandy berms along the south side of Reed’s Beach Road in the middle of the tiny New Jersey seaside community. A hundred or so shorebirds, mostly molting Sanderlings, were scattered on the damp sand next to the road. Most were asleep. My 800mm lens (with a single 50mm tube to allow for close focusing) was mounted on the car window with a Groofwin pod. Working in vertical format, I selected individual sleeping Sanderlings against uncluttered backgrounds, focused carefully, and squeezed off several frames. Every few minutes the restless birds would reshuffle, vying for better resting spots for themselves and creating new photographic opportunities for me. “Not bad for a drizzly day,” I thought. “With this soft light, I could be here for hours.”

I happened to glance in my side-view mirror and was not at all happy to see more than 40 poncho-clad birders walking briskly down the road past a row of houses directly toward my little beach party. “Surely they’ll see my 800mm lens sticking out of the car window, slow down, and observe the birds from the far side of the road,” I imagined. But the group kept coming, as oblivious to my photographic endeavors as they were to the light but now steady drizzle. In response to the group’s approach, many of the Sanderlings leaned forward and stretched both wings directly overhead. As the eager birders reached the rear of my car, all the shorebirds near the road took flight, including the few knots that had been feeding at water’s edge.

Getting on the bandwagon

Whether you’re birding or taking photos, it’s a good idea to always have a notepad at hand to record banded-bird sightings. At close range you will invariably be able to pick out a few color-banded shorebirds. Their legs will often look like little Christmas trees.

If possible, record the color and location of all bands and leg flags. The leg flag is a plastic band with a short tab, or extension. The color of the leg flag denotes the country in which the bird was banded. (I have seen blue-flagged birds from Brazil, orange from Argentina, white from Canada, black from Venezuela, and many green-flagged birds from the United States.)

Start with the left leg above the tarsus, then below. Do the same with the right leg. Record steel or aluminum Fish and Wildlife bands as “M” (for metal), and leg flags as “FL,” with the color in parentheses. For example: left leg, red over white above, M below. Right leg, orange over yellow above, FL (white) below.

Sightings of color-banded shorebirds should be reported to the Bird Banding Laboratory, U.S. Fish and Wildlife Service, Laurel, MD 20708 and to the International Shorebird Surveys, c/o Manomet Bird Observatory (MBO), P.O. Box 936, Manomet, MA 02345. Along with the band data, send the date, time, location, and if possible, the type and numbers of other shorebirds present.

In April 1981, Brian Harrington, director of the International Shorebirds Surveys at MBO, led the research team that recaptured two color-banded knots on the Atlantic coast of Argentina, birds that were originally banded by researchers in August 1980, at Scituate, Massachusetts! This pioneering work provided proof that Red Knots are indeed intercontinental migrants.

Every year hordes of northbound migrant shorebirds stop along the shores of Delaware Bay to feed on horseshoe crab eggs, attracting birders and nature photographers from across the continent (and beyond). Unfortunately, this influx of visitors can create problems for the birds, but with a few precautions, both birds and birders can enjoy this annual feast.

Horseshoe crabs are actually more closely related to spiders and scorpions than to true crabs. They begin coming ashore to mate in early May after leaving the deep waters of both the Atlantic Ocean and Delaware Bay. The smaller males, which greatly outnumber the females, follow them up the beach, where as many as five or six males may surround a single female.

The male that grabs the rear of the female’s carapace with its pedipalps (a specialized pair of claspers) is in the best position to fertilize the eggs. The females each bury several clumps of eggs (totaling tens of thousands) in the wet sand near the high-tide line.

Nest clumps are dislodged and exposed by wave action, other laying crabs, and by Ruddy Turnstones, which excavate two- to four-inch-deep holes. Anywhere from a half million to a million or more shorebirds stop along the beaches on both sides of Delaware Bay every year to feast on the horseshoe crab eggs, which are each no larger than a pencil point.

While shorebirds predominate, tens of thousands of gulls — mostly Laughing and Herring — and a wide assortment of passerines, led by Boat-tailed Grackles, regularly join the feast. Countless numbers of tiny fish gather to feed on floating eggs, and they in turn attract herons, egrets, and ibises.

In the late 1970s, Pete Dunne of the Cape May Bird Observatory alerted scientific and birding communities to the presence of huge flocks of refueling shorebirds on the shores of Delaware Bay. Dunne, David Sibley, Wade Wander, and Clay Sutton conducted the first aerial shorebird counts there in 1981 and 1982 in a single-engine Cessna Warrior 2.

Shorebirds are remarkably well-adapted long-distance fliers. Most of those that stop along Delaware Bay are on the way from their South American wintering grounds to breeding areas in the Canadian high Arctic. By gorging on horseshoe crab eggs (or other plentiful food sources in other locations), shorebirds can quickly accumulate layers of fat. These fat deposits, which at times can equal or exceed the birds’ lean weight, are converted into energy necessary to fuel 60- to 70-hour nonstop flights. Some flocks have been clocked by radar studies at speeds up to 60 miles per hour, at altitudes as high as 20,000 feet! Shorebird biologist J. Pete Myers calculated that for a Sanderling to double its weight in two weeks, it must consume an average of one egg every five seconds, 14 hours a day, for 14 days.

Like the crabs, the shorebirds begin arriving in early May, with their numbers peaking during the third or fourth week of the month. During the first week of June, numbers crash; after that, only a few stragglers and nonbreeding one-year-old birds remain.

Laughing Gulls, which breed in Atlantic coastal salt marshes, continue to fly to the bayshore, feeding on horseshoe crab eggs throughout June. Recent research shows that regurgitated horseshoe crab eggs are fed to gull chicks at the nest.

All those lucky enough to visit Cape May in the spring to witness the tremendous concentrations of horseshoe crabs and ravenous birds have a great responsibility to do all they can to minimize the disturbance of feeding and resting birds. Shorebirds that are flushed lose valuable feeding or resting time and expend energy that is needed to complete the last leg of their transcontinental migration. Additionally, the fat deposits accumulated at Delaware Bay provide energy stores that are crucial to the birds’ survival for the first few days after arriving on the Arctic breeding grounds, where conditions are often harsh.

Reed’s Beach is by far the best-known and most popular spot for observing the annual feast. There are only four shorebird-viewing vantage points along Reed’s Beach Road: the two sandy berms, previously mentioned, that abut the last two remaining undeveloped stretches of beach; the state viewing platform on the left, near the end of the road; and the rock jetty that begins at the very end of the road.

By standing on the road just behind either of the two berms, one can observe birds and crabs without disturbing them during most tidal stages. But at high tide, birders should move back to the far side of the road because the tide forces the birds to move higher up on the beach — and closer to the road. (Never climb up on the berms; a “tall” human silhouette will always flush the birds.)

For many reasons the state viewing platform is a great place from which to watch the activity. There are brochures, educational signs, and usually an intern to help first-timers and tourists. The platform is elevated, thus providing an excellent view of the beach and the birds. (Never attempt to approach feeding birds by walking toward them on an open beach.) There are usually some birds around whatever the tide. On high and high-outgoing tides the beach in front of the platform is usually jam-packed with birds (mostly knots and turnstones) and crabs. The platform is also a favorite gathering place for birders eager to alert others to the location of area rarities, which in recent years have included Mississippi Kite, Red Phalarope, White-winged Tern, Painted Bunting, and Scissor-tailed Flycatcher.

For those who wish to see what it would be like to be in the midst of a flock of speeding shorebirds, the rock jetty is the best place to be. Stand at the base of the jetty just before high tide and you will be deafened by the whoosh of wings as mixed flocks of knots and turnstones rush by just overhead on the way to lunch.

While Reed’s Beach is, justifiably, the most famous of the crab-egg beaches, there are other options available to birders and photographers wishing to observe feeding shorebirds at relatively close range. These lesser-known, seldom-visited beaches offer solitude, and they consistently harbor spectacular concentrations of birds and crabs. From Cape May Point west (and north), the crab-egg beaches lie along the bayshore as follows: the Villas, Norbury’s Landing, Pierce’s Point, Kimble’s Beach, Cook’s Beach, Reed’s Beach, Moore’s Beach, and Fortesque.

(The farther up the bay you go, the greater the number of Semipalmated Sandpipers. At the Villas or Reed’s Beach, it is often difficult to find even a single Semi; at Moore’s Beach in the mid-1980s, a flock estimated to contain one-quarter million of these peeps was noted!)

To obtain point-blank views of foraging migrants, birders or photographers can visit any of the crab-egg beaches except Reed’s (too many people) or Norbury’s Landing (the beach to the west is posted.) You should arrive about one hour before high tide and walk slowly up the beach to within 75 yards of a group of feeding birds. (They will not be disturbed at this distance.) Then, find a comfortable spot to sit just in front of the fore-dune. Sitting near some vegetation offers protective cover, but be careful not to crush any beach or marsh grass or other plants. Finally, remain still and wait.

Within an hour there should be hundreds of birds feeding nearby. By moving slowly when raising binoculars or aiming and focusing a scope or telephoto lens, you will not frighten the birds.

To photograph the mating horseshoe crabs and the windrows of eggs, it is best to visit the crab-egg beaches at low tide when the birds are scattered over thousands of acres of tidal flats and will not be disturbed by photographers crawling around in the sand with macro lenses.

Bird photographers standing erect should never attempt to stalk feeding shorebirds on open bayshore beaches; this is a surefire method for driving entire flocks from the egg-rich beaches. Whether you prefer sitting or lying on the beach or observing from a blind, it is important to get in position early and wait for the birds to come to you. Move only in slow motion — and watch out for those little old ladies.

Visitor information

Cape May Bird Observatory (CMBO) and the New Jersey Division of Nongame and Endangered Species have done much to educate beach-area residents and seasonal renters to the negative effects that sunbathing, beach parties, kite flying, boat launching, near-shore jet and waterskiing, misguided horseshoe crab “clean-up” efforts, and, of course, dog walking have on hungry migrant shorebirds.

CMBO director Paul Kerlinger urges all bayshore visitors to respect private property rights by observing the birds only from the road in residential and posted areas and by using common sense elsewhere, taking care not to disturb roosting or feeding flocks of shorebirds.

For more information about birding in the Cape May area, obtain a copy of David Sibley’s book, The Birds of Cape May (1993), published by the Cape May Bird Observatory. To purchase a copy, contact: CMBO, 707 E. Lake Drive, P.O. Box 3, Cape May Point, NJ 08212, (609) 884-2736.

Arthur Morris is based in Deltona, Florida. He is a full-time freelance photojournalist specializing in birds.