copyright Susan Detwiler |
Every year in late spring, thousands of horseshoe crabs crawl onto the beaches along Delaware Bay to mate. The females lay eggs in the sand. Between April and June, volunteers conduct a horseshoe crab survey, trying to get an idea of how many crabs are coming onto the beach that year.
Each year red knots and other shore birds gather on these same beaches to eat the horseshoe crab eggs. The red knot makes one of the longest migratory trips of any bird — 9,300 miles, from southern South America to its high Arctic breeding grounds. The horseshoe crab egg feast these birds consume at Delaware Bay is absolutely crucial for the birds’ survival. When the knots arrive at Delaware Bay, their bodies are half their starting weight, devoid of fat and even some muscle.
At the same time the crabs and red knots are congregating on the Delaware Bay beaches, you can see huge numbers of common green darner dragonflies as they pass through on their way north. Even larger groups of them pass through this same area when they fly south in the fall.