A seagull picked up a chihuahua in Devon, England, and flew off with it in its beak. The dog is still missing.

British seagulls have killed at least three dogs in the UK in recent years — their wingspans are more than five feet wide.

There's a reason gulls have become onshore predators. It relates to a sudden decline in the British fishing industry that started in the 1970s.

This is the story of how seagulls came to see dogs as food.

A large seagull snatched up a miniature chihuahua from a back garden in Devon, England, and the missing dog — named Gizmo — has not been seen since. The tiny pooch is just the latest in a line of pets that have been killed by Britain's influx of vicious seabirds.

At least three dogs have reportedly been killed by gulls in the UK in recent years. The birds — who have five-and-a-half-foot wingspans — have also eaten pigeons, ducks and lambs.

It's a real issue in UK coastal towns, which have become infested with the feral beasts.

Seagulls used to live largely out at sea, eating fish. But following a change in the British fishing economy in the 1970s, the gulls evolved their behaviour and now live in cities, feeding off garbage, human food, and — occasionally — picking off live pets from people's back gardens.

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These urban gulls don't bother going out to sea anymore. There is enough live food for them onshore.

Seagulls are omnivorous, meaning meat is part of their diet. In seaside towns like Brighton, it is impossible to eat food outdoors — gulls will swoop down and steal it from your hands.

This is the story of why the seagulls suddenly decided to ditch the sea and come live among the humans.