Den Sites of Possums, Trichosurus-Vulpecula, and Frequency of Use in Mixed Hardwood Forest in Westland, New-Zealand

Abstract

Forty-seven common brushtail possums, Trichosurus vulpecula, were radiotracked to 282 dens on 546 occasions. Just over half of all dens were in living trees; the remainder were evenly distributed between dead standing stems (including short stumps) and logs, with a few (3%) in banks and rock fissures. Of all the den entrances, 73% were at, or below, ground level amongst root systems or in logs. Although dead standing stems (over 25 cm d.b.h.) made up only 4% of standing stems in forest below 500 m altitude, they contained 41% of the dens. Each possum probably used between 10 and 15 dens each year. There were no differences in den choice and frequency of use between mature males and females. Den choice by matures and immatures was similar, but mature possums used dens in 'dead' sites more than did immatures. The implications of dens in the transmission of bovine tuberculosis are discussed.