There are a number of introduced mammals on St Helena that over the centuries have gone feral and pose a threat to the island’s biodiversity. These include cats, dogs, rabbits, rats and mice; donkeys and goats no longer roam free. Remote cameras have shown a number of mainland tropicbird and wirebird nests destroyed by cats, although there has been some improvement due to on-going trapping in affected areas; those caught animals without microchips have been humanely destroyed. In 2016, domestic dogs were observed damaging tropicbird nests at a couple of locations, leading to calls for improved supervision of pets. Rodent numbers are largely kept under control by the Government’s Environmental Health team and efforts of other organisations and land owners.