Full Moon, Shore Birds and Horseshoe Crabs May's full moon affects birds from the Atlantic to the Pacific—and everywhere in between. The full moon helps nocturnal hunters to see their prey, all the better for owls to catch more mice and Whip-poor-wills and nighthawks to see more insects. Woodcock sometimes perform their spring skydance all night long during a full moon. The full moon also affects ocean tides, making them stronger than normal. Higher tides affect food supplies for many shorebirds. One ocean creature, the horseshoe crab, comes out of deep water to spawn on beaches during high tides, and spawning increases during the strong tides of full and new moons. Scientist Kathryn Reshetiloff of the U.S. Fish & Wildlife Service's Chesapeake Bay Field Office in Annapolis wrote about the importance of these creatures:"The horseshoe crab (Limulus polyphemus) is found along the Atlantic Coast from Maine to the Yucatan peninsula. This fierce-looking yet harmless creature is valuable both ecologically and economically. Horseshoe crab eggs are an important food for shorebirds migrating along the Atlantic Coast. Horseshoe crabs are also used as bait in eel, whelk and catfish fisheries. Their importance doesn't end there. Horseshoe crabs are also used extensively for medical research." Right now along the Atlantic coast, horseshoe crabs are starting to appear on the beaches, along with the shorebirds that depend on this food to fuel their migration. The Cape May Bird Observatory is trying to protect the crabs from being overharvested. Then the shorebirds that depend on them can survive. To learn more, see: Shorebird Crisis: The Horseshoe Crabs of Delaware Bay Try This! Journaling Questions In many kinds of shorebirds, males do most, or even all the work of raising the babies. In some species, like phalaropes, males even incubate the eggs. Why do you think the shorebird family has so many males working harder than females? The bright, full moon also helps people to see migrants! In the 1950s, ornithologists named Lowery and Newman focused a telescope on the moon and saw hundreds of birds winging past. They learned many things about migration that ornithologists had never known for certain before. What do you think they learned? In what ways, if any, could the full moon be a hindrance to the nighttime migrants themselves? After you write your thoughts, compare here. If you know anyone with a telescope or binoculars, see if you can see any migrants flying past the moon. Can you identify them? Write about what you see! Copyright 2004 Journey North. All Rights Reserved. Please send all questions, comments, and suggestions to our feedback form