Document ID: chunk:federal_register_of_legislation:F2024L01095:body:0:p32
Version: federal_register_of_legislation:F2024L01095
Segment Type: other
Provision Reference: 
Character Range: 83790–86744

Sub-adult birds (14–28 months old) survived better than the younger juveniles released in the same areas, although fox predation still accounted for about 70% of birds that were released. Studies have also demonstrated that intensive fox baiting increases the survival of captive-reared birds released in the wild (Copley and Williams 1995, Priddel and Wheeler 1997), and a population of Malleefowl has been successfully re-introduced to Peron Peninsula following intensive predator and exotic herbivore control (C Sims pers. comm. cited in Benshemesh 2007b).

A common element in all these studies is that chick cohorts of any age encounter massive mortality rates during the first few days after they are released. Thereafter, mortality rates decline as birds spend more time in a habitat, and this possibly reflects the development of experience by the birds in finding reliable food sources and in evading predators. This pattern is most pronounced for chicks and captive-reared juveniles, but also applies to captive-reared sub-adults. It is also worth noting that all releases of radio-tagged Malleefowl less than a month old have occurred late in the breeding season, whereas it is characteristic for avian breeding success and offspring survival to be highest early in the breeding season and decline thereafter (Perrins 1970, Rohwer 1992).

Fox control improves the survival of captive-reared birds, but the degree to which fox predation is responsible for the decline of existing Malleefowl populations is less clear. Foxes are most common in mallee near agricultural land where high densities may be maintained by the ready availability of their principal foods such as rabbits, mice and sheep carrion (Saunders et al. 1995). However, many of the highest Malleefowl breeding densities occur in such areas and have appeared stable in the absence of habitat disturbance or drought (Frith 1962a, Benshemesh 1992, Copley and Williams 1995).

The relationship between fox predation and Malleefowl declines is still unclear but is being investigated by the national Adaptive Management Predator Experiment (AMPE) (Hauser et al. 2019, Benshemesh et al. 2018). While monitoring data over the past three decades, and several decade-long studies do not suggest that Malleefowl benefit from baiting programs that reduce foxes, it may nonetheless be warranted to reduce fox (and cat) numbers where Malleefowl populations show clear signs of decline. Reducing predator populations is especially important when rabbit numbers are suddenly reduced, such as following the spread of rabbit haemorrhagic disease, as this may lead to 'prey-switching' by foxes (Pech and Hood 1998), as similarly recorded for cats (McGregor et al. 2020).

Fox inspecting a Malleefowl mound, ©Graeme Tonkin, NMRG.

4.2.7 Weeds
Weeds in general (with the exception of buffel grass) are not a specific threat to Malleefowl but compete with native plants, therefore reduction in weeds