CAPE ELIZABETH – There’s a crime wave at Maine beaches, and it seems to be getting worse as the summer heats up.

People who leave their food-laden belongings unattended quickly find a gang rifling through their stuff. Other times, the thieves wait until someone’s guard is down before snatching something right out of his hands.

The criminals are sea gulls, and park rangers say it always gets worse as summer progresses.

“There’s no doubt about it: They’re brazen,” said Dan Watson, a ranger at Crescent Beach State Park.

On a recent day at the park, a toddler was accosted by a dozen squawking gulls that knocked over drinks, scattered french fries and swiped a cheeseburger from the picnic table where the boy was sitting.

A gull recently dive-bombed another patron, hitting her on the arm and causing her to drop a hamburger, a snack bar worker said. The gull grabbed the burger and scampered away.

The scene plays out up and down the coast like a never-ending clip from Alfred Hitchcock’s “The Birds.”

Common culprits are herring gulls and great black-backed gulls, which are familiar to anyone who has visited the New England coast.

They frequent beaches, marinas, fish-processing plants, garbage dumps and just about any other place where there’s a free meal. Though no postcard-perfect harbor scene would be complete without them, some Mainers derisively refer to them as “rats on wings.”

During the late 1800s, the number of gulls dropped because people either broke their eggs or harvested them, said Bruce Connery, a biologist at Acadia National Park on Mount Desert Island.

These days, gulls are flourishing to the point they’re competing for nesting space with other seabirds, he said.

Meantime, the dumps that once provided a ready source of food have been closed for environmental reasons.

One easy new source of food is the scraps some beach-goers enjoy tossing at them. That has contributed to aggressiveness by teaching gulls to associate people with food, Connery said.

Down the road from Crescent Beach, the Two Lights Lobster Shack has signs warning people not to feed the gulls. Unfortunately, the gulls sometimes feed themselves, said owner Martha Porch.

“We’ve had sea gulls take a whole lobster from a plate and one day we had a sea gull take a wig off a woman’s head. One of my employees chased the sea gull down and it finally dropped the wig,” Porch said.

The gulls have a keen sense for an opportune time to strike – for example, when someone’s attention is diverted during conversation. But the most daring gulls don’t wait, as when a ranger’s friend had her lunch stolen recently at Crescent Beach.

“The sea gull landed on her friend’s head, then proceeded to grab the sandwich,” Watson said.

Getting mugged by a gull changes people’s image of gulls as cute seabirds on postcards. So does their size: Great black-backed gulls can have wingspans of more than 5 feet.

For a person, taking someone’s lunch could constitute theft, or even robbery when force is used.

But sea gulls are protected by the Migratory Bird Treaty Act of 1918, so no harm is allowed to come to them.

Options for getting rid of them are limited, said Ralph Blumenthal, operations manager for Atlantic Exterminating.

For starters, people can make their property less attractive to gulls with simple steps such as closing trash bins or building enclosures around the places where they roost, he said.

Noise can repel the birds, and a substance that irritates their feet can be placed in roosting areas, he said.

As a last resort, property owners can petition the U.S. Fish and Wildlife Service for permission to eliminate a nest. Owners first must demonstrate they’ve done everything else possible to shoo the birds away.

Judy Walker, staff naturalist for the Maine Audubon Society, knows gulls can be annoying. She also knows people contribute to their bad behavior by feeding them.

Since there’s little to be done other than to stop feeding them, she suggests that people focus on the positive. “They’re very elegant. If they weren’t so common, we’d appreciate them more,” Walker said. “They’re pretty. They’re beautiful fliers. They seem to fly just because they enjoy it.”

Audubon Society gull facts

The Associated Press

Facts about gulls from Judy Walker of the Maine Audubon Society:

. Technically, there is no such thing as a “sea gull”; various species are referred to that way.

. There are 14 gull species in Maine. Most common are herring gulls and great black-backed gulls.

. Gulls are big. The wingspan for herring gulls is 58 inches and the span for great black-backed gulls is 65 inches.

. Gulls are opportunistic eaters. They’ll eat just about anything, including fish, insects and trash.

. Gulls can live 15 years.