Participation: Sea Gulls and the Invasive Green Crab

Within an hour of observation during low tide, gulls were an efficient predator of the invasive green crab.

Three types of gulls were observed.

Herring gulls were the most common at 4 individuals (2 juveniles). One black backed gull also visited the scene, preying on a single green crab. In terms of which crustaceans were preyed upon the most, 3 spider crabs and 6 green crabs were taken from the shallows in total, indicating that green crabs are an established part of certain gull diets in this area.

I have known this area to be highly populated by green crabs. Below is a photo taken by myself in July when learning the average size of green crabs in Cohasset. The crabs were collected from under the Border St. Bridge, near where the sea gulls were hunting crabs.