Categorization and discrimination of "chick-a-dee" calls by wild-caught and hand-reared chickadees

Bloomfield and Sturdy [Bloomfield, L.L., Sturdy, C.B. All chick-a-dee calls are not created equally. Part I. Open-ended categorization by sympatric and allopatric chickadees. Behav. Proc., in press] previously reported that black-capped chickadees (Poecile atricapillus) discriminate conspecific from heterospecific (mountain chickadee, P. gambeli) 'chick-a-dee' calls, and their ability to accurately discriminate and classify the calls as belonging to separate species' defined categories was largely unaffected by their prior experience with mountain chickadees and their calls. To further examine the potential influence of experience on discrimination and categorization, we compare wild-caught black-capped chickadees, wild-caught mountain chickadees, and black-capped chickadees hand-reared among either adult laboratory-housed black-capped chickadees or adult laboratory-housed mountain chickadees on a true category/pseudo category chick-a-dee call discrimination task. Irrespective of group assignment, hand-reared birds performed as well as wild-caught birds and did not show a conspecific- or rearing-specific advantage in discrimination, categorization or memorization of chick-a-dee calls. While vocal learning is under the influence of ontogenetic experience, the results derived from the current methods suggest that experience (or a lack thereof) does not affect categorization and memorization abilities.