IF YOU GO looking for wallabies around the Ballaugh Curragh, a mossy wetland on the Isle of Man, you will almost certainly find them. They will cautiously look in your direction, hopping away only if you step on a twig or get too close. A wild population of red-necked wallabies, named after their distinctive patch of rust-coloured fur, has lived on the island since the 1960s, when a few escaped from a wildlife park. Some conservationists feel the time has come to intervene.