Seed type, predator, and social influences on foraging blackcapped chickadees (Poecile atricapillus)

Food quality, predator cues, and social interactions influence how an animal forages. The suburban environment exposes animals to artificial food sources (e.g., bird feeders) and different predators not usually encountered in the wild. Perhaps most notable of novel suburban predators is the domestic cat (Felis catus). I presented free-ranging chickadees and their mixed-species flock members a cat decoy and two different seed types, sunflower and safflower, in either single-feeder or dual-feeder presentations. Chickadees engaged in foraging behaviors rather than active anti-predator tactics. Chickadees preferred sunflower seeds over safflower seeds, and the social interactions were largely influenced by seed type. Chickadee contact calls increased around the less visited feeder, possibly to initiate collective movement to a different feeding site. Alarm calls may have been used as an aggressive behavior to eliminate competition, rather than as an anti-predator alarm or defense tactic. Presentation of a predator did not directly influence chickadee foraging activities, but chickadees gave slightly more high-alarm calls when a predator was presented. Future investigation should focus on intra- and interspecific interactions that vary based on different predators and how these predator cues affect a bird's foraging behavior in a suburban environment.