Quick question: How much do you weigh?
OK, now try to imagine the sort of marathon physical ordeal you’d have to put yourself through in order to lose half of your body weight. OK, now try to imagine that you’ve been through that ordeal, and you are suddenly facing a deadline—in just two weeks, you have to eat enough food to get back up to your normal weight.
If you fail, chances are pretty good you’re going to die.
Meet the red knot, an amazing salmon-colored shorebird that may well have the longest migration trip of any bird in the world. Red knots spend their summers about as far north as you can get, high up in the Arctic, and they spend their winters about as far south as you can get, down at the lower tip of South America or Australia. Their journey is nearly 10,000 miles long.
What does all this have to do with Southern Delaware? Well, the red knots have evolved with an instinct that has them passing our way at a particularly critical time in their journey. They have been through that physical ordeal, losing half of their body weight. They are both exhausted and starving.
Horseshoe crab eggs make for easy gorging. Oh man, can these prehistoric-looking creatures ever lay eggs! Females dig holes in the sand and then lay a few thousand eggs at a time. Then they do it again and again—one horseshoe crab can lay up to 120,000 eggs between the start of the spring mating season and the end.
In one article I read, a scientist compared horseshoe crab eggs to peanuts—they’re basically small gobs of fat that are really easy to swallow. That is precisely what the red knots need on this stopover. The birds stay in our area for about two weeks, during which time their job is basically to do nothing but eat, 24/7, and get back to a normal body weight.
Just thinking about the way these shorebirds found their way to these feasting grounds over the long stretch of centuries tends to boggle the mind a little. Experts say the birds have been making this stop for something like 10,000 years now, since back when woolly rhinoceroses and saber-toothed cats still roamed the earth and our human ancestors were just starting to figure out this newfangled thing called farming.
As with most any good nature story, there are complications to report here. About 100 years ago, we humans began to harvest horseshoe crabs in bigger numbers than ever before. At first, the crabs were used in fertilizer and animal feed. Nowadays, it’s more as bait for conch and eel pots.
There is the scientific angle involved as well. The blood of horseshoe crabs contains a chemical critical to the process of testing medicines for purity. Many thousands of horseshoe crabs every year are caught so that they can give some blood. They are then returned to the wild, but estimates of how many crabs die during this process range from 5 to 30 percent.
Bottom line: There are fewer horseshoe crabs than there used to be, though recent studies have concluded that the population is stable for now. Both Delaware and New Jersey now have much stricter regulations about harvesting horseshoe crabs, so hopefully the population will continue to hold steady.
This natural wonder is something you can and should go see for yourself along the beaches on the Delaware Bay. The best time to go is May and early June—in my limited experience, crabs and shorebirds should be around most of the day in that period. Experts say that the best time to go is in the evening, at high tide, around the times of the new and full moons. If you happen to see any crabs laying upside down on the beach while on this adventure, you can do your part for the revival of the species by flipping them back to right-side up.
Pretty much all of the beaches mentioned in this Road Trip are good candidates for horseshoe expeditions (Slaughter Beach, Bowers Beach, Prime Hook National Wildlife Refuge, Broadkill Beach, Fowler Beach). The beaches farther north are generally good spots as well. If you check in with the volunteers at the DuPont Nature Center, they might be able to tell you which particular beaches are getting good reports from visitors at the time of your visit.
—Written by Jim Duffy for Secrets of the Eastern Shore/Whimbrel Creations LLC. All rights reserved.
NOTE: This is an excerpt from Eastern Shore Road Trips #1: 27 One-Day Adventures on Delmarva.