Justification

This species is Extinct in the wild. The last sighting in its natural habitat was in 1972. There are probably less than a hundred in captivity and a reintroduction is planned.

Threats

The decline and extinction in the wild of Z. graysoni has been attributed chiefly to predation by cats. However, it was thought that cats became feral on Socorro in the 1950s, but this date has now been revised to the early 1970s². This suggests that other factors, such as human predation and high levels of understorey grazing by sheep, may have been significant.

Conservation

A proposal is currently being developed to reintroduce the species¹. Some control of feral cats has been undertaken, but there are now plans to eradicate cats and sheep³. Reports that rats have recently colonised Socorro have proved to be unfounded².

Targets

*Eradicate cats and sheep from Socorro. *Reintroduce the species following the completion of this eradication programme.