Acoustic discrimination of predators by black-capped chickadees (Poecile atricapillus)

• Published in: Animal cognition 2020-05, Vol.23 (3), p.595-611
• Main Authors: Congdon, Jenna V., Hahn, Allison H., Campbell, Kimberley A., Scully, Erin N., Yip, Daniel A., Bayne, Erin M., Sturdy, Christopher B.
• Format: Article
• Language: English
• Subjects: Acoustics; Animal behavior; Animals; Auditory Perception; Behavioral Sciences; Biomedical and Life Sciences; Birds; Birds of prey; Body size; Discrimination, Psychological; Life Sciences; Operant conditioning; Original Paper; Perception; Perceptions; Predators; Psychology Research; Songbirds; Species; Training; Transfer of training; Vocalization, Animal; Wing span; Zoology
• ISSN: 1435-9448; 1435-9456
• DOI: 10.1007/s10071-020-01364-5

Smaller owls and hawks are high-threat predators to small songbirds, like chickadees, in comparison to larger avian predators due to smaller raptors’ agility (Templeton et al. in Proc Natl Acad Sci 104:5479–5482, 2005). The current literature focuses only on high- and low-threat predators. We propose that there may be a continuum in threat perception. In the current study, we conducted an operant go/no-go experiment investigating black-capped chickadees’ acoustic discrimination of predator threat. After obtaining eight hawk and eight owl species’ calls, we assigned each species as: (1) large, low-threat, (2) mid-sized, unknown-threat and (3) small-, high-threat predators, according to wingspan and body size. Black-capped chickadees were either trained to respond (‘go’) to high-threat predator calls or respond to low-threat predator calls. When either low-threat predator calls were not reinforced or high-threat predator calls were not reinforced the birds were to withhold responding (‘no-go’) to those stimuli. We then tested transfer of training with additional small and large predator calls, as well as with the calls of several mid-sized predators. We confirmed that chickadees can discriminate between high- and low-threat predator calls. We further investigated how chickadees categorize mid-sized species’ calls by assessing transfer of training to previously non-differentially reinforced (i.e., pretraining) calls. Specifically, transfer test results suggest that mid-sized broad-winged hawks were perceived to be of high threat whereas mid-sized short-eared owls were perceived to be of low threat. However, mid-sized Cooper’s hawks and northern hawk owls were not significantly differentially responded to, suggesting that they are of medium threat which supports the notion that perception of threat is along a continuum rather than distinct categories of high or low threat.