 Breeding and release programs began in 1965 and have successfully brought seven of the eight endangered subspecies up to less perilous population levels . Young tortoises are raised at several breeding centres across the islands to improve their survival during their vulnerable early development . Eggs are collected from threatened nesting sites , and the hatched young are given a head start by being kept in captivity for four to five years to reach a size with a much better chance of survival to adulthood , before release onto their native ranges . 
