SURVIVAL OF AVIAN CARCASSES AND PHOTOGRAPHIC EVIDENCE OF PREDATORS AND SCAVENGERS

Abstract

Scavenging of carcasses may bias estimates of mortality following the use of pesticides. To assess carcass survival, we monitored bird carcasses in crop stubble, grassland, roadside, and wooded habitats in east-central South Dakota in early spring. Survival rates differed among habitat types in 1997 but not in 1998. Survival rates did not differ among species of carcass in 1997 or 1998. Within 5 d, 66% of carcasses had been scavenged in both 1997 and 1998. To assess potential hazards of secondary poisoning, we used infrared-triggered camera systems to identify predators and scavengers of live birds and bird carcasses. Mammals (n = 164), particularly striped skunks (Mephitis mephitis) (n = 105), were the most commonly photographed predators and scavengers. The number of avian predators and scavengers photographed (n = 39) was relatively low. Because scavenger activity can be high, we recommend that searches for carcasses should be conducted within 24 h of pesticide application to ensure accurate estimates of mortality.