Nocturnal behaviour of the parma wallaby, Macropus parma (Marsupialia : Macropodoidea)

Commercial night-vision devices permit the study of nocturnal behaviour wit hout visible light sources, obviating concerns about the effects of supplem ental lighting on natural behaviour. We used an inexpensive image intensifi er to document the previously unstudied nocturnal behaviour of the parma wa llaby, Macropus parma Waterhouse, 1846, based on a captive population of 6 male and 6 female sexually mature wallabies. A total of 150 h of observatio n was conducted over 34 nights and 6 days. The circadian rhythm of this spe cies was grossly similar to that of many other Macropodoidea, although ther e was a pronounced peak in activity at dawn. The behavioural time budgets o f males and females were reliably different, with males spending more time actively foraging than females. Social interactions were rare in both sexes , but we were able to characterise sexual behaviour in detail. Courtship ty pically began with sexual checking of the female by the male, after which t he male pawed the female's rump repeatedly. This was occasionally followed by mounting and copulation, but typically the male presented his chest, dra wing the female's head toward it with his forepaws. While this 'head rubbin g' is clearly homologous with components of social behaviour in other walla bies, it seems uniquely elaborate in parmas. Interactions between males and females were accompanied by characteristic vocalisations. Males produced r epeated broad-band 'clucking' sounds while grooming females, who often resp onded by hissing. The structure and context of these signals suggest that c lucks function to stimulate the female, while hisses probably encode threat . It is likely that males produce both olfactory and acoustic signals durin g courtship; such cues could play a role in mate choice decisions by female s. Our results demonstrate that nocturnal observations on small macropodids are feasible and suggest that more reliable information about social behav iour is obtained at night.