In an event that rivals the swallows' return to Capistrano, over one million shorebirds converge on the Delaware Bay each spring. The bay is the second largest feeding stopover in the western hemisphere for northbound shorebirds. It's such a critical link that lower Delaware estuary was designated as the first reserve in the Western Hemisphere Shorebird Reserve Network.

Some shorebirds, like the red Knot, take off from the tip of South America in April. They make only one major pit stop on the southeast coast of Brazil before flying 5,000 miles nonstop to the Delaware Bay.

The shorebirds are lured to the Bay by a banquet of little green eggs. More horseshoe crabs spawn here than anywhere else on earth. Drawn ashore by the lunar high tides in May, male crabs vie to mate. Each female lays up to 80,000 eggs per season in several nests. Latecomers accidentally dig up shallow nests, exposing thousands of eggs to ravenous shorebirds.

By late May, some 30 species of shorebirds bent on doubling their body weights cram the shoreline. Scientists calculate that a sanderling weighting 50 grams on arrival will eat one horseshoe crab egg every five seconds for 14 hours a day.

Shorebirds use their probing bills to feed, reaching only the top layer of eggs, which are not viable. Nests buried deeper than one-half inch are safe. Refueled, they depart for the arctic nesting grounds.