Gough Island in the South Atlantic is used by 20 species of seabird for breeding, including almost all of the world's Tristan Albatross (Diomedea dabbenena) and Atlantic Petrel (Pterodroma incerta). Until house mice arrived on the island in the 19th century with seamen, the birds did not have any mammalian predators. The mice have since grown unusually large and have learned to attack albatross chicks, which can be nearly one metre tall but are largely immobile, by working in groups and gnawing on them until they bleed to death. The estimated 700,000 mice on the island kill a total of over 1 million bird chicks per year.
A short video of mice gnawing on chick:
Gangs of house mice have been caught attacking and killing seabirds 300 times their weight on an island in the South Atlantic Ocean. House mice (Mus musculus) were thought to pose little risk to island birds, until now. Video footage exposes tiny house mice as they invade the nests of young chicks and proceed to gnaw through chicks' feathers and skin before gorging on their entrails. One video showed up to 10 mice mauling an albatross chick and eating from three open wounds on its body.
Though the mice are three times larger than their European cousins, weighing as much as 1.41oz (40g), they are dwarfed by the fledgeling sea birds that have become their prey. An albatross chick weighs up to 22lb, some 250 times the weight of the rodents.
The birds, however, are virtually immobile and must be protected from attack by adults, who spend many hours away fishing for food. The mice gnaw the live chicks, their wounds become infected and they die. “It is like a tabby cat attacking a hippopotamus,” said Geoff Hilton, a senior research biologist with the Royal Society for the Protection of Birds (RSPB).