On a Gulf of Maine estuary a Herring Gull takes off with its crab. An abundance of crabs are carried into the estuary on an incoming tide. The current is strong enough to mix the crabs throughout the entire water horizon and carry then across sand bars. Gulls need only continually circle above the current to eventually spot a crab near the surface. Gulls cannot dive, so they must instantly drop to the water to catch their crab before it is carried into deep water again.