Low tide is a dangerous time for the crabs that live on the edges of the North Basin. These Western Gulls can read the telltale bumps in the mud where the crustaceans try to conceal themselves. The first gull in the video uncovers a crab about as large as its head but manages to swallow its entire body in a couple of gulps, going back for the legs. No tedious cracking the shells and picking out the meat like we humans do. Just down the hatch; the gull’s digestive system will sort it all out. Shortly thereafter the same gull uncovers another crab, larger than the first, and very feisty. The bird drops the crab and walks away. But then a fellow gull comes along. The crab’s vigorous defense backs the bird off twice. But then the bird snatches the crab by one leg and carries it off toward the shallow water. In a few moments it’s curtains for the crustacean.
I don’t know what kind of crabs these are/were. Judging by the photos on SFBayWildlife.org, these might be Purple Shore Crabs, but that’s just a guess.
These gulls are formidable predators. At the Pt. Reyes National Seashore I saw a gull tackle a much larger crab — a crab of the size that humans might be served for dinner. The bird flipped the crab over and then proceeded to eat its innards alive. Gulls can unhinge their jaws to swallow surprisingly large prey. On YouTube there is a video of a gull killing and swallowing a Ground Squirrel.