Regions Of Eastern Australia Research Articles

A study of the biology of the wild rabbit in climatically different regions in eastern Australia. I. Patterns of distribution

Patterns of distribution of warrens of the wild rabbit Oryctolagus cuniculus (L.) in subalpine, subtropical, and semi-arid areas are described. At Snowy Plains, a subalpine valley in eastern New South Wales, 866 warrens occurred on an area of 9 square miles. There were 175 warrens per square mile on open country grazed by stock, but only 9 warrens per square mile on adjacent forested country. At Mitchell, in subtropical southern Queensland, 871 warrens were mapped on 165 square miles. There were 44 warrens per square mile on alluvial deposits of sand along the margins of the Maranoa River and less than one warren per square mile in other habitats. At Tero Creek in semi-arid north-western New South Wales, 4910 warrens were mapped on 250 square miles. Warren density per square mile was 38 on sand dunes, 19 on stony tablelands, eight on flat desert loams, six on stony pediments, and none on Mitchell grass plains. The preferred habitat was sand. Mean warren size and distribution of warren sizes varied significantly between sites and habitats. The upper limit to warren size lay between 50 and 60 burrow entrances per warren. The largest mean warren size occurred in the heavier soils. Mean warren size in sandy soils and in areas where rabbit control was practised was lower. Patterns of use of warrens also showed significant differences from habitat to habitat. At Snowy Plains the smaller warrens were more inactive and at Mitchell and Tero Creek the larger warrens were more inactive. After a harsh, dry summer at Tero Creek a further significant decrease in activity in the larger warrens was measured. Predation on nestling rabbits by foxes (Vulpes vulpes L.) was confined almost completely to warrens in sandy soils. Traverse sight-counts of rabbits above ground at night showed good correlation between warren distribution and rabbit numbers. Distribution of rabbit populations in relation to warren distribution is discussed.

A study of the biology of the wild rabbit in climatically different regions in eastern Australia. II. Seasonal changes in the pelt

Data are presented on moulting in the wild rabbit, Oryctolagus cuniculus (L.), at four sites in eastern Australia — subalpine, semi-arid, subtropical, and Mediterranean. The Australian wild rabbit moults twice a year. A spring–summer moult, which shortens the fur for summer, progresses from the ventral surface towards the dorsal (dorsad) and an autumn–winter moult, in which longer and more wavy fur grows, progresses from the dorsal surface to the ventral (ventrad). During the breeding season the pattern of moulting in females becomes scattered. Rabbits under 3 months old appear to have consecutive moults which usually progress dorsad, irrespective of season. The wave pattern of the moults becomes less regular with increasing age. In the subalpine area moulting was limited to definite seasons and was completely absent during the cold winter. At the other three sites where the winter was milder, moulting occurred throughout the year but still with definite peaks of ventrad moulting in spring–summer and of dorsad moulting in autumn-winter.