Falkner Island is the largest common tern colony and only roseate tern colony in Connecticut. Terns nest in large groups for protection from both aerial and ground predators. These seabirds lay their eggs on the ground on sand, gravel, or grass. When predators are seen, the whole colony of birds – more than 4000 on Falkner – will fly up and dive at and defecate on the predator. Roseates are federally endangered; there are only about 100 of them left in Connecticut. They nest with the more abundant common tern to protect their eggs/chicks from being eaten by gulls, crows, and herons.