Crocodylus johnstoni in the McKinlay River Area N. T, II.* Dry-Season Habitat Slection and an Estimate of the Total Population Size

Abstract

In July 1979, midway through the dry season, most C, johnstoni were congregated in pools greater than 1m deep and 900 m2 in area. Use of some, but not all of these large, deep pools is not dependent on whether the pools are in the mainstream or not, nor on the clarity (an indicator of siltation) of the water in them. Food availability and access to nesting banks may be related to selection of individual pools, although the former is considered unlikely. The homing ability of C. johnstoni would seem a decided advantage for relocating specific refuge sites, which tend to be used each year by the same individuals. The C. johnstoni population in the McKinlay River study area is estimated at 963 individuals (826- 1156).