Predation event and shelter site use by a threatened monitor lizard, Varanus rosenbergi, in the Little Desert, Victoria

Abstract

Heath monitors (Varanus rosenbergi) are arguably the most thoroughly studied Australian varanid, largely stemming from long-term research on Kangaroo Island, South Australia. However, research on other populations within this species' disjunct distribution is limited. We opportunistically tracked a heath monitor in the Little Desert National Park, Victoria, after it consumed a painted dragon (Ctenophorus pictus) which we were radiotracking for another study. We report the first record of a heath monitor depredating a painted dragon, as well as the first record of heath monitors repeatedly using a hollow log for shelter. The hollow log was occupied on 10 consecutive occasions over 18 days, and then again on five occasions 9–11 months later. Our observations identify hollow logs as a habitat resource which should be considered in conservation strategies for this threatened monitor lizard. Furthermore, we observed two individuals in close proximity, possibly a breeding pair, in January. This implies that breeding may occur in summer for the Victorian mallee population, as has been reported in other populations, rather than in spring as has been speculated. Research is sorely needed across this species' disjunct distribution across southern Australia. To date, populations of heath monitors in the Victorian mallee have garnered no scientific study, despite their listing as Critically Endangered.