A population study of the quokka, Setonix brachyurus (Quoy & Gaimard) (Marsupialia)

Abstract

A general account is given of the quokka, Setonix brachyurus, and its habitat on Rottnest Island.

Apart from relatively long-distance (up to 2000 yd) excursions to water-holes or to rubbish dumps, quokkas have a rather restricted individual range, but do not appear to be territorial in any way. Aggregations occur at water-holes throughout the summer, and at rubbish dumps all the year, but only animals from some adjacent parts of the island are involved. The quokkas on Rottnest can fairly clearly be grouped in at least five more or less discrete subpopulations. No evidence was obtained of a dispersive phase during immaturity.

The main season of births is from February till May, though a few young were born in each month except December. In 1956 births were recorded about a fortnight earlier than in 1955. The incidence of breeding is compared in the Bagdad and Serpentine populations.

Growth of pouch young and the weights of other age groups are given and discussed. Different subpopulations are compared and significant differences exist.

It is shown that adults lose weight and young animals do not grow well during the hot dry summer.