Temporal activity patterns of the swamp rat ('Rattus lutreolus') and other rodents in north-eastern New South Wales, Australia

The activity patterns and partitioning of time by four small mammal species, with a focus on the swamp rat ('Rattus lutreolus') in north-eastern New South Wales, was investigated using camera trap data from two studies. Analysis was carried out on 1079 camera trap events over 1530 camera trap-nights or 36 720 h of camera trap deployment in the field. The activity patterns of 'Rattus lutreolus' were distinctly diurnal with crepuscular peaks of activity but this differed between sites and when in the presence of competitors. The Hastings River mouse ('Pseudomys oralis') and the bush rat ('Rattus fuscipes') displayed typical bimodal patterns of nocturnal activity. Antechinus were mostly nocturnal but were occasionally active during the day. These data indicate that where species of Muridae co-occur, diurnal time partitioning by 'R. lutreolus' may reduce competition for food resources. It also confirms the speculation that 'R. lutreolus' displays diurnal behaviour, albeit dependent on the presence of other murids.