Data from: Megafires attract avian scavenging but carcasses still persist

Data collection Our study was conducted in the Wolgan Valley in the Blue Mountains, south-eastern New South Wales. Carcass monitoring was conducted over three 1-month periods in the warm seasons of summer and autumn. The first two monitoring periods were conducted before a fire, in January 2018 and 2019, and the third was conducted in March of 2020. During each monitoring period, we distributed 20 adult eastern grey kangaroo carcasses in an equal mix of open grassland (hereafter “open canopy”; n=10 sites) and forest (hereafter “closed canopy”; n=10 sites) habitat. Open canopy sites were at least 50 m from any stands of trees. The closed canopy sites had more than 20% canopy cover before the fire, and in the post-fire period carcasses were placed in forested locations where there was previously canopy cover of more than 20%. Within monitoring periods, carcasses were separated by at least 1 km to mitigate scent travel between carcasses. Between monitoring periods, however, carcasses were positioned at least 100 m from any previous carcass placement. We used dead kangaroos sourced from nearby management culls, so no animals were killed for the purpose of this study. Any carcass displaying evidence of disease (e.g. heavy parasite loads) was not used. All carcasses were placed into the field without freezing within 24 hours of collection (i.e. all at the same time, with 24 hours being the longest time between the first and last carcass placement; January 2018; 9:00 – 23:00, January 2019; 8:00 – 13:00, and March 2020; 23:00 – 6:00). Scientific licenses/permits were obtained to relocate the kangaroo carcasses (SL 101901) and research was approved by the University of Sydney Animal Ethics Committee (Project number: 2017/1173). To allow for ongoing monitoring and detection of scavengers visiting and feeding on each carcass, we used a Reconyx PC800 Hyperfire™ camera trap (Professional Reconyx Inc., Holmen, WI, USA) attached to a free-standing star picket 3–4 m away from each carcass. The cameras were programmed to take continuous photographs when triggered by thermal movement around the carcass (rapidfire, no wait period). To prevent complete removal of the carcasses from the remote camera monitoring frame, we secured carcasses to the ground by wire attaching the neck and achilles tendon of the animal to two metal stakes spaced ~0.6 m apart. Cameras were used to monitor carcasses for 30 days to capture the main period of vertebrate scavenging activity and because the majority of carcass biomass (including meat, skin and bones) were removed from the environment in this time. Data processing Camera images were tagged according to each new carcass visitation event by a different species, the number of individuals of a species present, whether any of the individual species fed on the carcass or not, and the date and time that the observation was recorded. A visitation event was considered new if it occurred ≥ 10 min from the previous visitation event by the same species. We defined scavenger species as species that were observed feeding on at least one carcass over the three study periods. All other animals captured on the remote cameras were excluded from our analyses. Finally, using a combination of in-person visual inspection of the carcasses and inspection of camera images, we determined the number of days until complete carcass consumption. A carcass was defined as completely consumed when less than 5% meat biomass and only skin, hair and/or bone remained.