Soon after the founding of the United States, the father of American ornithology, Alexander Wilson, was studying its birds in South Jersey. He was the first to describe 26 of the new nation’s avian species and he named one, the Cape May Warbler, for what has been a birding capital ever since.
Cape May’s global reputation is based on the very wide range of bird species found in the area over the years, and on two natural phenomena of global significance.
One is its famous fall hawk migration, with tens of thousands of raptors concentrating at the peninsula’s tip as they head south. The other was its annual spring invasion of more than 100,000 shorebirds on its Delaware Bay beaches — until people killed most of the horseshoe crabs whose eggs fed the birds.
The peak of the spring shorebird migration was a spectacle that stunned everyone with the power and beauty of natural life, and drew bird watchers from overseas. It was as if the bay beaches in mid-Cape May County had been replenished with feathers — colorful spring plumage alive and frenetically feeding.
Tens of thousands of ruddy turnstones and sanderlings were the supporting cast for the stars of the show, from 80,000 to 100,000 red knots. They were fresh in from their wintering grounds at the bottom of South America in the midst of their incredible 9,000 mile flight to nesting grounds in the Arctic north.
This dramatic demonstration of nature’s abundance, strength and beauty was made possible by one of the world’s most distinctive creatures — the horseshoe crab. Not a crab at all but an arachnid (a distant relative of the spiders in the garden), the horseshoe crab is unchanged since it scuttled across the salty bottom 450 million years ago. It embodies that prehistoric age with a bulging primitive gray-green shell roughly the shape of a horse foot (it’s common name of old), with a stiff tail that looks menacing but is harmless and used to turn itself over when waves topple it.
Scientific interest in the horseshoe crab has included its blue blood, which has a factor that can detect bacterial contamination in medical applications, and one of the earliest animal visual systems. Its simple eyes used mainly to distinguish the sex of fellow horseshoe crabs (females are much larger) make that judgment within the eye and alert the rest of its body through giant optic nerves — so big that scientists can attach a monitor to a single nerve.
Guided by more than a billion full-moon tides, the horseshoe crabs have rushed ever-changing shorelines to mate and release massive quantities of tiny green eggs — enough to color the wave wash, refuel migrating shorebirds and keep their own species thriving.
But then they were decimated by the abundance of humans and the ease with which people could simply pick them up when they came ashore to mate and chop them up for such low-value uses as snail bait and fertilizer. Even though an alternative bait that greatly reduces the use of horseshoe crabs has been available for several years, many catching eels and snails (also called conch, whelk or scungilli) still just kill cheap horseshoe crabs to bait their pots,
The green eggs on the bay beach plummeted from 100,000 per square meter to 5,000 to 8,000 in 2017. With fewer horseshoe crabs, the spring shorebirds dwindled. The red knots alone fell to 30,000.
Credit New Jersey environmental officials for recognizing the unjustifiable loss. The state imposed a moratorium on taking horseshoe crabs — unique wildlife that belongs to all of the public — in 2008.
Unfortunately, on the other side of the bay, Delaware has allowed the taking of horseshoe crabs for commercial gain to continue (although it does supposedly restrict the taking to males). Other key states such as Maryland and Virginia also allow the taking of horseshoe crabs.
The red knot subspecies rufa depends on its Cape spring pit stop, so this wanton destruction of South Jersey’s spring shorebird migration runs afoul of the federal Endangered Species Act. In 2014, it was listed as a threatened species.
New Jersey’s actions have stabilized the shorebird and horseshoe crab populations, but conservation groups such as NJ Audubon, the American Littoral Society and others rightly want to restore them to past levels by 2030. They are mounting a campaign to persuade other states to also suspend horseshoe crab harvesting.
The Atlantic States Marine Fisheries Council’s new stock assessment for horseshoe crabs, released in May, looks helpful. It said managing their population must take into account “the needs of shorebirds such as the red knot,” which means restricting the catch to males until “the abundance of red knots reaches 81,900 birds.”
Such efforts should continue until the spring shorebird spectacular — one of the key components of South Jersey’s multi-billion ecotourism segment — is restored to the Cape beaches on Delaware Bay.
The human species has been around less than a quarter of a percent of the horseshoe crab era. If people can’t stop themselves from destroying natural phenomena of global significance and living fossils that were already ancient when mammals first appeared for the sake of fertilizer and bait, how long will Homo sapiens leave itself a place in life?