Dr. Elphick said, and ornithologists and birders speculate, that the closing of open landfills like Fresh Kills on Staten Island may have something to do with the drop in numbers since then. “There’s many a birder, especially those who’ve been around for 20 to 30 years, who will complain about the closing of landfills and how it’s removed their best places to go watch gulls,” he said.

Dr. Sarah J. Courchesne has been part of a summer gull research program at the Shoals Marine Laboratory on Appledore Island, Me., since 2008.

She admits that the herring gulls and black-backed gulls there do not always take kindly to visitors. But these are breeding colonies, and the researchers take young birds off the nest, examine them and put identification bands on them.

“This is like somebody walked into your house in the night and picked up your child and tried to walk off with them,” she said. “You would be alarmed.”

As are the gulls. So much so that the volunteers wear bike helmets and sometimes ponchos. Gull poop can ruin a shirt.

“Some gulls are just kind of psycho and others are really chill,” she said. Some birds sit quietly on a nest and allow themselves to be lifted off by volunteers who check the babies.