By: Dr. Larry Niles, LJ Niles Associates LLC
The value of a shorebird stopover like Delaware Bay can be seen in the shaky cam movie by this author. Red knots – some recently arrived after a grueling 6,000-mile flight over 6 days of continuous flying – arrive on the Bayshore desperate for food. Over the last 10,000 years, the species has evolved to fly directly to the Bay to feed on the eggs of the horseshoe crab.
The 450-million year-old crab – which is actually in the spider family – crawls ashore and lays pin-sized eggs about 6 inches deep in the sand. When there are many crabs, as here on Delaware Bay, one crab often unearths the eggs of another. Thus they leave millions of fatty eggs on the surface, offering an energy-rich, soft feast for the starving birds. In turn, we get to watch the birds racing for an egg ‘hot spot’!
The birds often arrive beyond depleted. A normal weight for a knot is 130 grams. Many arrive on Delaware Bay below 100 grams, the equivalent of a human in the throes of profound starvation. But when the birds fly north from the coast of northern Brazil, there’s no turning back. Once they go, they must go all the way.
Map of geolocator track of a South American wintering red knot
Read more: 2015 Delaware Bay shorebird project continues