MORTALITY OF CAPTIVE-RAISED MALLEEFOWL, LEIPOA-OCELLATA, RELEASED INTO A MALLEE REMNANT WITHIN THE WHEAT-BELT OF NEW-SOUTH-WALES

Loss, fragmentation and degradation of mallee habitat within the New S outh Wales wheat-belt have caused a marked decline in the range and lo cal abundance of malleefowl, Leipoa ocellata. Small disjunct populatio ns of malleefowl now occupy small isolated remnants of suitable habita t, and several of these populations have become locally extinct in rec ent times. Young captive-reared malleefowl (8-184 days old) were exper imentally released in March and June 1988 into a 558-ha remnant of mal lee vegetation. The remnant contained a small but declining population of malleefowl. From the first day after release, malleefowl were foun d dead, and mortality continued at a rapid rate until none remained al ive. Of the 31 released, 16 (52%) were dead after 7 days, at least 22 (71%) were dead after 11 days, and none survived longer than 107 days. In all, 94% of malleefowl were killed by predators: 26-39% by raptors , and 55-68% by introduced predators, principally foxes, Vulpes vulpes . No improvement in survival was evident when malleefowl were given su pplementary food. Relying principally on camouflage, young malleefowl have no effective defence or escape behaviour to evade ground-dwelling predators such as the fox. By imposing severe predation pressure on y oung malleefowl, foxes are likely to be curtailing recruitment into th e breeding population. Such a situation must inevitably lead to the fu rther localised extinction of small disjunct populations of malleefowl . Foxes are thus a major threat to the continuance of remnant populati ons of malleefowl within the wheat-belt of New South Wales.