EFFECTS OF SCAVENGING ON ASSUMPTIONS OF MORTALITY ANALYSES OF RADIO-MARKED GAMEBIRDS

Abstract

Survival estimation is critical to studies of wildlife population biology, and recent model developments allow for temporal covariates on mortality risk. To test model assumptions that scavengers do not influence either perceived mortality cause or location, we randomly placed 24 radio-marked Chukar (Alectoris chukar) carcasses over gradients of grassland habitat conditions in eastern Montana in both April 2017 and July 2018, and monitored scavenging activity at intervals relevant to gamebird telemetry studies. High rates of scavenging (12.5–78%, depending on season and relocation interval) suggest that scavenging activity could confound determination of cause-specific mortality, but that its influence varies with season. Scavenging activity did not significantly influence perceived mortality locations regardless of season or local habitat conditions with a relocation interval of 3 d (8% of carcasses moved), but mortality locations may be biased over longer periods (50% of carcasses moved in 7-d period), particularly in warm seasons or regions.