New Zealand biologists have undertaken an extraordinary – and probably unique – effort to save a colony of endangered lesser short-tailed bats, the most land-based of the world’s bats. First, they captured pregnant females, which gave birth and raised a total of 20 pups in captivity. Then they released the pups in a predator-free forest reserve on Kapiti Island, in hopes that will assign their homing instinct to this new home.
The problem that has plagued efforts to transplant bats from areas of high risk to more congenial sites is their very strong homing instinct. A previous attempt to transfer adult bats from one island to another failed when, from all indications, the bats simply flew back to their original home. New Zealand Conservation Minister Chris Carter says that if this “cunning solution” works, it could invaluable for preserving New Zealand’s two surviving bat species.
Both species, found only in New Zealand, evolved in a land almost free of ground-based predators. But now they are under constant attack by non-native animals – rats, feral cats, ferrets, weasels and possums – and by the continuing loss of habitat to farms and towns.
The lesser short-tailed bat (Mystacina tuberculata) survives now only in a handful of locations in New Zealand. These remarkable bats spend much of the night running up tree trunks and along branches or burrowing in the leaf litter and humus on the forest floor searching for food. Such scampering is possible because of a unique method of folding their delicate wings to protect them from injury. They walk on robust hind legs and feet and use their forearms as front legs.
The New Zealand Department of Conservation captured the pregnant bats from a threatened colony on Tararua Forest Park and took them to the Pukaha Mount Bruce National Wildlife Centre. The 20 pups were born between Christmas 2004 and late January 2005. For about four weeks, pups were nursed by their mothers. After the young learned to fly, however, the mothers were returned to their Tararua home, and the pups were introduced to carefully selected habitat areas on Kapiti Island.
So far, the bats seem to be accepting their new home and staying put on the island.
BCI members can read the whole story of this remarkable New Zealand project in the Summer 2005 issue of BATS magazine.