No abstract

Captive breeding is a high profile management tool used for conserving threatened species. However, the inevitable consequence of generations in captivity is broad scale and often-rapid phenotypic divergence between captive and wild individuals, through environmental differences and genetic processes. Although poorly understood, mate choice preference is one of the changes that may occur in captivity that could have important implications for the reintroduction success of captive-bred animals. We bred wild-caught house mice for three generations to examine mating patterns and reproductive outcomes when these animals were simultaneously released into multiple outdoor enclosures with wild conspecifics. At release, there were significant differences in phenotypic (e.g. body mass) and genetic measures (e.g. G st and F) between captive-bred and wild adult mice. Furthermore, 83% of offspring produced post-release were of same source parentage, inferring pronounced assortative mating. Our findings suggest that captive breeding may affect mating preferences, with potentially adverse implications for the success of threatened species reintroduction programmes.

Camera trapping has evolved into an efficient technique for gathering presence/absence data for many species; however, smaller mammals such as rodents are often difficult to identify in images. Identification is inhibited by co-occurrence with similar-sized small mammal species and by camera set-ups that do not provide adequate image quality. Here we describe survey procedures for identification of two small, threatened rodent species – smoky mouse (Pseudomys fumeus) and New Holland mouse (P. novaehollandiae) – using white-flash and infrared camera traps. We tested whether observers could accurately identify each species and whether experience with small mammals influenced accuracy. Pseudomys fumeus was ~20 times less likely to be misidentified on white-flash images than infrared, and observer experience affected accuracy only for infrared images, where it accounted for all observer variance. Misidentifications of P. novaehollandiae were more common across both flash types: false positives (>0.21) were more common than false negatives (<0.09), and experience accounted for only 31% of variance in observer accuracy. For this species, accurate identification appears to be, in part, an innate skill. Nonetheless, using an appropriate setup, camera trapping clearly has potential to provide broad-scale occurrence data for these and other small mammal species.

Extreme weather conditions, such as drought, significantly decrease the survival and breeding success of numerous species. Despite the frequent occurrence of such conditions in Australia, little is known about the effects of changing environmental conditions on the native small mammals. This study, conducted from 2002 to 2004, focussed on sympatric wild populations of the agile antechinus (Antechinus agilis), with more limited information on the dusky antechinus (A. swainsonii) and the bush rat (Rattus fuscipes). Bodyweights of agile antechinus before and during the breeding season were significantly lower in 2003 (drought) than in 2002 or 2004. Survival of female agile antechinus and the number of young per litter also decreased significantly during drought. In contrast, the dusky antechinus showed no difference in mean bodyweights between years, high survival rates of females and similar litter sizes in 2002 and 2003.There was also no difference in bodyweight of bush rats between years. Low rainfall was recorded during pregnancy and lactation in the agile antechinus, but rainfall was higher during pregnancy and lactation in the dusky antechinus. The survival and breeding success of the agile antechinus may have been adversely affected by a combination of interspecific competition, timing of the breeding season and severity of the drought. Effects of drought on weight, survival and breeding success of agile antechinus (Antechinus agilis), dusky antechinus (A. swainsonii) and bush rats (Rattus fuscipes)

Modern zoos are increasingly taking a leading role in emergency management and wildlife recovery. In the face of climate change and the predicted increase in frequency and magnitude of catastrophic events, zoos provide specialised expertise to assist wildlife welfare and endangered species recovery. In the 2019–2020 Australian bushfire season, now called Australia’s Black Summer, a state government-directed response was developed, assembling specialised individuals and organisations from government, non-government organisations, research institutions, and others. Here, we detail the role of Zoos Victoria staff in wildlife triage and welfare, threatened species evacuation and recovery, media and communications, and fundraising during and after the fires. We share strategies for future resilience, readiness, and the ability to mobilise quickly in catastrophic events. The development of triage protocols, emergency response kits, emergency enclosures, and expanded and new captive breeding programs is underway, as are programs for care of staff mental health and nature-based community healing for people directly affected by the fires. We hope this account of our response to one of the greatest recent threats to Australia’s biodiversity, and steps to prepare for the future will assist other zoos and wildlife organisations around the world in preparations to help wildlife before, during, and after catastrophic events.