Suchergebnisse

Stomach contents were studied for 289 live young crocodiles (Crocodylus porosus) less than 180 cm long, collected from coast, river and swamp of Arnhem Land, Melville Island and Grant Island, Northern Territory, Australia; the crocodiles were then released. Tables give orders and families and some generic and specific names for prey or carrion eaten and for 3 parasites on the crocodiles, for a dry and a wet season in 1975-76. Between crocodiles 50 to 120 cm long and those smaller or larger there was no significant difference in the proportion of crocodiles having eaten crabs, shrimps, fish or insects or with empty stomachs, but only the larger crocodiles ate mammals or birds. Frequency of different foods eaten differed significantly with type of habitat or with salinity. Weight of food or incidence of empty stomachs did not differ between seasons, habitats or salinities. Condition of the crocodiles was significantly poorer for those from freshwater swamps than for those from lower mangrove or flood plains, and highest for those from upper mangrove. Main foods in both seasons were crustaceans, mainly crabs of subfamily Sesarminae and shrimps of genus Macrobrachium. The only fish eaten regularly was Pseudogobius sp., a slow-moving fish found by the water's edge. Amphibians were not found in the stomach.

Relationships among ground surface features attributable to feral buffalo (viz. wallows, trails, pug marks
and dung pats), vegetation structure, and lifeform spectrum were examined in both dry and wet seasons
in a tropical monsoonal area of northern Australia. In the dry season, the frequency of pug marks was
negatively correlated with the number of trails and dung pats, and positively correlated with the number
of wallows. In the wet season only dung pats and wallows were significantly correlated. In the dry season,
wallows were not associated with any vegetation structure or lifeform attribute, but in the wet season
they were associated with dense foliage <1 m high. Trails occurred in areas of low dense vegetation
(<0.5 m) in the dry season, but in the wet were uncommon and positively associated with lianas. Pug
marks occurred mainly in the lower-elevation, treeless areas dominated by forbs. Whereas the nature
and strength of the relationships of pug marks to plant lifeform or vegetation structure remained
constant from season to season, those involving dung pats changed seasonally. In the dry season, dung
pats were associated with the higher-elevation areas where trees, lianas, dense mid-level foliage
(1.5-2.5 m) and leaf-litter were common. In the wet, they were associated with low vegetation (<1 m)
dominated by forbs, and were negatively correlated with the factors important in the dry.

Descriptions and measurements of two series of known age embryos of C. porosus are given. Eggs
for one series were incubated at temperatures ranging between 27.5 and 29,5"C, the other between
30.5 and 31.5D C. Comparison with these series should allow estimation of the approximate time when
eggs were laid in the field when the temperature of the nest is known.

This paper presents the results of an aerial survey for potential nesting areas of C. porosus along the
western coast of Cape York Peninsula, Queensland, from the tip of the Cape to the Norman River.
There is a decrease from north to south in the amount of suitable nesting habitat. Many suitable nesting
areas occur north of the Embley River, where relatively higher relief favours the development of freshwater
swamps with a low risk of seasonal flooding. Further south, the broad, alluvial plains and
meandering rivers are often subject to extensive flooding and fewer opportunities for nesting are available.
General conclusions only are given, and management discussed. Detailed results are lodged with
the Australian National Library, Canberra (catalogue No. MS5640).

Results of a study of habitats used by C, povosus for nesting on the Liverpool and Tomkinson Rivers, Arnhem Land, northern Australia, are presented. These were used as the basis of an aerial survey for potential crocodile nesting habitat in coastal wetlands between Smith Point (Cobourg Peninsula) and Gove.

General conclusions of the survey are given, and areas in which different types of management could be applied are indicated. Detailed results are lodged with the Australian National Library,Canberra (catalogue No. MS5640).

One X. myoides was captured on the bank of the Tomkinson River, Arnhem Land, and three on the banks of Andranangoo Creek, Melville I.

The latter specimens, an adult and two juveniles, were in a mud mound containing a nest. The remains of a fifth specimen were recovered from the stomach of a Crocodylus porosus caught in the Tomkinson River.

All specimens were associated with mangrove forests. Behavioural observations are presented and discussed. X. myoides could be more widespread in the mangroves which border northern rivers.