The Influence of population density and habitat on grouping in the western grey kangaroo, Macropus fuliginosus

1993 ◽  
Vol 20 (2) ◽  
pp. 151 ◽  
Author(s):  
G Coulson

Population density and habitat structure have been identified as influencing grouping patterns in kangaroos, but the separate contributions of each factor have rarely been distinguished. Grouping was examined in the western grey kangaroo, Macropus fuliginosus, at Hattah-Kulkyne National Park, north-western Victoria, where the population exhibits marked changes in density throughout habitats that provide a range of cover. Group size and population density in each habitat were surveyed at two times of day and at roughly 2-monthly intervals from March 1983 until December 1985. Of the four major habitats, mallee and woodland offered moderate cover, whereas grassland and lake bed gave sparse cover. Visibility of kangaroo groups was highest in the sparse habitats, and was positively related to the size of the group, at least in the lower range of group sizes. At densities up to 40km-2, groups that formed in the sparse habitats were larger than the groups in the two habitats that offered moderate cover. Three habitats (lake bed, grassland and woodland) had more smaller and more larger groups than expected if group formation was a random process. Large males were seen alone more often than expected by chance in lake bed, and less often in moderate cover; females with young-atfoot were over-represented as singletons in all four habitats. The size and composition of groups recorded in this study suggest that the basic components of the social organisation of kangaroos are best discerned in habitats that carry a low population density, but that also provide the most cover.

1993 ◽  
Vol 20 (2) ◽  
pp. 137 ◽  
Author(s):  
G Coulson

The western grey kangaroo, Macropus fuliginosus, typically occurs at highest population densities in areas of greatest habitat heterogeneity. Hattah-Kulkyne National Park, in semiarid north-western Victoria, supports a relatively high density of this species, and has a mosaic of four major vegetation associations: mallee, woodland, lake bed and grassland. The patterns of habitat use by western grey kangaroos at Hattah-Kulkyne were examined from March 1983 until May 1985 using line-transect surveys to estimate population density in each habitat, and radio-tracking to estimate home range. The population was not dispersed randomly, but generally exhibited either positive or negative preferences for each of the four habitats in early morning and at midday, and on different bimonthly surveys. These preferences often reversed between times of day and between surveys. Home ranges of individuals ranged from 221 to 459 ha (asymptotic MAP[O.95] estimates), each encompassing three or four habitat types, and there was extensive spatial and temporal overlap between individuals. Kangaroos at Hattah-Kulkyne thus alternated between adjacent habitats that offered a range of forage conditions and shelter.


1984 ◽  
Vol 11 (3) ◽  
pp. 437 ◽  
Author(s):  
CJ Southwell

The effects of season, population density and habitat on aspects of group formation in the eastern grey kangaroo were examined. The rate at which groups join and split increased exponentially with population density, but did not vary with season or habitat. In general, large males and females with young-at-foot were seen alone more frequently than small males, females with pouch young or females with no young. The high frequency oflone large males may be due to a tendency to move alone from one group to another to check the oestrous condition of females, but females with young-at-foot appear to be relatively solitary. Association among population classes in groups of two or more was highly variable.


2018 ◽  
Vol 24 (1) ◽  
pp. 98
Author(s):  
Michael Hughes ◽  
Valériane Bérengier

This research note documents an observation of a wild western grey kangaroo (Macropus fuliginosus) feeding on a dead silver gull (Chroicocephalus novaehollandiae) at Lucky Bay in the Cape Le Grand National Park on the south coast of Western Australia. Published evidence suggests that this behaviour is not unique and could be widespread in Western Australia and further afield. We consider why the kangaroo may be feeding on the dead gull and possible implications for conservation programs relying on poison meat baits to control introduced species.


1988 ◽  
Vol 15 (3) ◽  
pp. 257 ◽  
Author(s):  
GL Norbury ◽  
GM Coulson ◽  
BL Walters

The study was carried out at Hattah-Kulkyne National Park in semiarid north-west Victoria, during 3 years immediately following a severe drought. A sample of animals which died as a result of the drought (n= 196) and a shot sample (n=546) were examined to determine patterns of breeding, mortality and age structure. Births were concentrated in spring and summer, with a peak in November. Only 46% of mature females bred during the drought, whereas 100% bred two seasons later. The sex ratio of pouch young was not significantly different from parity, but showed a slight male-bias, however, the sex ratio of the adult population was markedly female-biased (1:3). Projected population growth was not realised in the years following the drought because of high mortality. There was evidence of male-biased mortality which was apparently accentuated during the drought. This biased mortality appeared similar in all adult age classes, and may have been a consequence of the disparate energy costs imposed by sex differences in body size and in mobility.


1992 ◽  
Vol 19 (5) ◽  
pp. 565 ◽  
Author(s):  
PC Thomson ◽  
K Rose ◽  
NE Kok

Between 1975 and 1984, 105 radio-collared dingoes, Canis familiaris dingo, were tracked and observed from aircraft on the Fortescue River in Western Australia. The majority of dingoes were members of 18 territorial packs, including four pairs. Five packs were monitored for more than three years. Most bitches became pregnant, including those 9-10 months old, although not all litters were raised. Packs raised an average of 1.1 litters per year. Instances of packs raising the litters of two bitches in a year were recorded. The area (up to 400km*2) was covered initially (1975-78) by a mosaic of stable pack territories. Little emigration occurred and population density rose to a peak of 22.2 dingoes per 100km*2 in 1978 due to an increase in pack size. Perturbations to the social system, including disintegration of some packs, an increase in emigration, shifts of pack territories and contraction of territories into the most favoured areas, coincided with high population density and a reduced food supply. After aerial baiting in 1980 killed all the dingoes from the study site, immigrants from surrounding areas established a new population. The increase in density was moderated by the formation of new pairs or packs that occupied surrounding vacant areas. The dispersal strategy of pack members was a major factor affecting the population density of dingoes in the study area.


1992 ◽  
Vol 40 (2) ◽  
pp. 205 ◽  
Author(s):  
AN Andersen ◽  
AY Yen

Ants were collected from the canopies of mallee eucalypts at Wyperfeld National Park in north-western Victoria by beating foliage on ten occasions from September 1979 to December 1980. The study was conducted at two adjacent sites: one that had been burnt by a wildfire during early 1977, and the other long unburnt. Both sites contained a mixture of three mallee eucalypt species: Eucalyptus dumosa, E. foecunda and E. incrassata. In contrast to the canopies of other eucalypt formations elsewhere in southern Australia, abundance and diversity of ants were very high. Ants represented 43-69% of all invertebrates, and a total of 44 ant species from 19 genera was collected. Iridomyrmex and Camponotus respectively contributed 10 and 11 species, and the most abundant ants were species of Iridomyrmex, Monomorium and Crematogaster. Ant composition was broadily similar at the two sites, and on different canopy species, although significant differences in abundance were apparent for some individual ant species. Except for tree-nesting Podomyrma adelaidae and Myrmecorhynchus sp. nr emeryi, the fauna was dominated by ground-nesting species, most of which appeared to forage on vegetation opportunistically. The unusually high abundance and diversity of the canopy ant fauna are attributed to the close proximity of the mallee canopy to the ground, coupled with an exceptionally rich ground ant fauna.


2007 ◽  
Vol 158 (11) ◽  
pp. 349-352
Author(s):  
Grégory Amos ◽  
Ambroise Marchand ◽  
Anja Schneiter ◽  
Annina Sorg

The last Capricorns (Capra ibex ibex) in the Alps survived during the nineteenth century in the Aosta valley thanks to the royal hunting reservation (today Gran Paradiso national park). Capricorns from this reservation were successfully re-introduced in Switzerland after its Capricorn population had disappeared. Currently in Switzerland there are 13200 Capricorns. Every year 1000 are hunted in order to prevent a large variation and overaging of their population and the damage of pasture. In contrast, in the Gran Paradiso national park the game population regulates itself naturally for over eighty years. There are large fluctuations in the Capricorn population (2600–5000) which are most likely due to the climate, amount of snow, population density and to the interactions of these factors. The long-term surveys in the Gran Paradiso national park and the investigations of the capacity of this area are a valuable example for the optimal management of the ibexes in Switzerland.


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