Effectiveness of head-starting to bolster Philippine crocodile Crocodylus mindorensis

The freshwater Philippine crocodile Crocodylus mindorensis (endemic to the Philippine archipelago) is the most threatened crocodilian in the world with an estimated wild population of less than 100 mature individuals. Due to low survival of wild hatchlings, a head-starting program was initiated in 2005. Hatchlings are collected from the wild just after hatching and released back into their natural habitat after being raised in captivity for 14-18 months. Several ponds were created to provide suitable release habitat. Between 2005 and 2008, 88 hatchlings were collected. Hatchling survival after one year in captivity was 63 out of 88 (72%), compared to 47 % for 36 hatchlings monitored in the wild (as low as 13 % in some areas). Thirty two head-started crocodiles were released back into the wild (31 still held in captivity in 2009). Of the 32 released crocodiles, minimum survival after one year in the wild was 50%. Post release observations and recaptures showed that the released juvenile crocodiles adapted well to natural conditions and were increasing in size. The ultimate goal of the program will only be achieved if the head-started crocodiles survive to maturity and reproduce