Conditions in a Manx marshland wallabies escaped to in the 1960s proved “almost perfect” for an expansion in the population to 1,000, a conservation charity has said.

Only a small number managed to break out of a nearby wildlife park, but recent surveys of the Ballaugh Curragh and its surrounding areas show numbers have swelled.

Manx Wildlife Trust chief executive Leigh Morris said the habitat was similar to Tasmania, which was one of the places the species is native to.

That allowed the wild population to grow in the north-west of the island, before migrating to other glens and forests over the past six decades, he said.