Coyotes eat flies at carrion

Coyote (Canis latrans) are a generalist carnivore that are presumed to be a facultative scavenger. However, we observed feeding behavior that calls into question the simplicity of this interaction. During a carcass deployment experiment, we recorded 105 potential coyote feeding observations, of which 44 included information regarding the food item being consumed. Adult necrophagous flies accounted for these detailed observations as often as carrion (21% of all potential feeding events). Most observations of necrophagous fly consumption occurred at a single block during a restricted window of time, which could reveal individual variation in coyote diet. Our finding highlights the importance of characterizing indirect food web interactions at carcasses. In our case, coyotes likely encountered necrophagous flies in the process of scavenging at carcasses. Food webs may thus include dependencies (e.g., necrophagous flies reproducing on decomposing organic matter) that can generate spatiotemporally limited interactions involving facultative consumers. Moving forward, researchers can advance knowledge regarding food webs by defining the complete suite of consumer interactions at resource pulses.