Date of this Version
Trebac, C. I. (2023). Social transmission of predator information through referential alarm calls within and across species Undergraduate Honors Thesis, University of Nebraska-Lincoln.
Animals can encode information about a predator’s size, identity, or threat through alarm calls. This can provide referential information that can be used by individuals within and across species receiving the information. Referential alarm calls can encode information through changes in structure or rate of the call, and these variances in their call can elicit different responses, such as fleeing or mobbing, in conspecifics and heterospecifics. We aimed to investigate whether white-breasted nuthatch alarm calls can encode referential information and elicit different responses from conspecifics. Previous studies showed that a related species of nuthatch varies their call rate in the presence of direct predators and mob more aggressively to heterospecific alarm calls that encode information, but no studies have evaluated if the varied calls of nuthatches subsequently elicit more aggressive mobbing behavior in conspecifics. Our study evaluated the mobbing behavior of white-breasted nuthatches in response to a high-rate conspecific alarm call, a low-rate conspecific alarm call, and a control. The resulting high-rate and low-rate conspecific alarm calls by playing referential black-capped chickadee alarm calls to white-breasted nuthatches, and these high-rate and low-rate nuthatch alarm calls were then played to white-breasted nuthatches. We performed trials in forested locations with dense tree cover distal from loud roadways with moderate human foot traffic. White-breasted nuthatches elicited mobbing behavior in response to high-rate and low-rate alarm calls in the form of horizontally approaching the speaker from which the alarm call played. However, the nuthatches’ mobbing behavior was not statistically significant between the high-rate and low-rate conspecific alarm calls. This study gives insight into the propagation of predator information through species commonly associated with each other and the potential implications of eavesdropping and responding to alarm calls within and across species.