By Sally Bickley Goose Island's proximity to oyster reefs explains its attraction to waterbirds. The reefs surround the island and offer an abundant menu for many shorebirds. The island might even be an oyster reef itself, washed over with shell and sand, which allowed plants to take hold. The fishing pier is built on an oyster reef extending into the bay. Birding around Goose Island State Park offers rewards at any season Oyster reefs form when the mollusks cement themselves to a hard foundation.
Oysters then create a hard shell from the calcium in the seawater.
Barnacles, mussels and other mollusks stick to the oysters' shells, creating an amplitude of nooks and crannies. The crevices provide hideouts for crabs, snapping shrimp and nematode worms. Blue-green algae grow on the shells. More oysters and mussels attach themselves at every angle to the group. The reef grows upward and outward, depending on the nutrient flow of the water.