Platypus Activity Areas and Patterns in a Sub-Alpine Tasmanian Lake System.

Abstract

The seasonal activity patterns and habitat usage of platypuses were examined in Lake Lea, a sub-alpine lake system in north western Tasmania. Activity data were collected by radio tracking individuals for one 24 hour period (in two 12 hour blocks) using a portable radio-receiver and 3-element Yagi antenna. In addition, the location of other individuals was recorded periodically during the 24 hour period. Information collected so far for ten individuals during late winter and mid spring will be presented. Preliminary analysis suggests that a high proportion of the population may be diurnally active. Out of five adult platypuses tracked during late winter, three were predominantly diurnally active and only two were nocturnal. Day-active individuals emerged from burrows between 0530 and 0700 and returned before 1930, thus foraging for at least 13.5 hours per day. Nocturnal individuals emerged between 1730 and 1900, foraged for approximately 12.5 hours and returned between 0600 and 0700. Mean dive times of three day-active individuals were between 29 and 34 seconds, with an intervening surface period of between 12 and 20 seconds. Maximum foraging area of three individuals were between 14 and 30 hectares (95% isopleth, Kernel analysis).