Do Male Mountain Chickadees Discriminate between Local and Non‐Local Elevation Intruders?

Abstract

Song in temperate songbirds is typically learned from local males and commonly thought to function in mate choice and male–male competition. Because male song is learned locally and is phenotypically plastic, it often varies geographically and may serve as a cue for an individual's location of origin. In montane environments, environmental heterogeneity occurs across the elevation gradient, potentially leading to local adaptations on rather small spatial scales. If local adaptations are associated with restricted movements between elevations, this leads to the question of whether individuals can discriminate between birds from the same vs. different elevations. Mountain chickadees inhabiting high and low elevations are known to differ in numerous phenotypic traits, including male song structure. In addition, we previously reported that female high‐elevation mountain chickadees can discriminate between local and non‐local elevation males and here, we tested whether males also respond differentially to high‐ vs. low‐elevation male territory intruders. Playback stimuli were presented to resident high‐ (N = 24) and low‐ (N = 20) elevation males at our previously established study sites during spring to compare the males' behavioral responses to high‐ and low‐elevation male song playbacks. Both high‐ and low‐elevation males responded similarly to both types of playback stimuli, suggesting that they do not differentially respond to male intruders from their location of origin compared to non‐local males. These results are considered in the framework of our previous findings and the larger body of literature, which suggests that male songbirds readily discriminate between local and non‐local male intruders.