Acoustic mechanisms of a species-based discrimination of the chick-a-dee call in sympatric black-capped (Poecile atricapillus) and mountain chickadees (P. gambeli)

• Main Authors: Lauren M Guillette, Tara M Farrell, Marisa eHoeschele, Christopher B Sturdy
• Format: Article
• Language: English
• Published: Frontiers Media S.A. 2010-12-01
• Series: Frontiers in Psychology
• Subjects: black-capped chickadee; operant conditioning; songbird vocalizations; Chick-a-dee call; Mountain chickadee; Species discrimination
• Online Access: http://journal.frontiersin.org/Journal/10.3389/fpsyg.2010.00229/full

Previous perceptual research with black-capped and mountain chickadees has demonstrated that these species treat each other’s namesake chick-a-dee calls as belonging to separate, open-ended categories. Further, the terminal dee portion of the call has been implicated as the most prominent species marker. However, statistical classification using acoustic summary features suggests that all note-types contained within the chick-a-dee call should be sufficient for species classification. The current study seeks to better understand the note-type based mechanisms underlying species-based classification of the chick-a-dee call by black-capped and mountain chickadees. In two, complimentary, operant discrimination experiments, both species were trained to discriminate the species of the signaller using either entire chick-a-dee calls, or individual note-types from chick-a-dee calls. In agreement with previous perceptual work we find that the D note had significant stimulus control over species based discrimination. However, in line with statistical classifications, we find that all note-types carry species information. We discuss reasons why the most easily discriminated note-types are likely candidates to carry species based cues.