Activity patterns, movements and burrows of platypuses (Ornithorhynchus anatinus) in a sub-alpine Tasmanian lake

Adult male and female platypuses were radio-tracked in summer and winter at Lake Lea, north-western Tasmania. They appeared to exhibit greater diurnality, particularly during winter months, a greater degree of overland movement and more frequent use of non-earth refuge sites than do animals inhabiting mainland water bodies. Individuals foraged continuously for up to 16 h, with longer foraging bouts observed during the winter tracking period. Foraging range varied between 2 and 58 ha, with no significant differences observed between the sexes or seasons. All platypuses foraged predominantly in the lake; however, a number of animals were observed moving overland to and from waterbodies and burrows. Burrows were located on lake, creek and pool edges. A high percentage of burrows (25%) were located within dense sedge tussocks and scrub vegetation. Both the terrestrial activity and more opportunistic burrow-site selection may be related to reduced predation pressure in Tasmania.