A Complex Call of the Black-Capped Chickadee (Parus atricapillus). I. Microgeographic Variation

Abstract

Abstract We studied the syllabic structure of the Gargle, a complex vocalization of the Black-capped Chickadee that is often associated with agression, at three main sites in southeastern Wisconsin, at one site over an 11-yr period. Sites as close as 5.7 km showed major differences in syllables, and birds at some sites differed somewhat in the number of syllables per call. Each individual probably uses all the syllables (16-23 different ones) occurring at a particular site. The syllables occurring at the end of the vocalization were shared among different demes, while the introductory syllables were usually different. Syllables showed relatively little change with time. Dialects apparently correspond to demes in this species. The syllables are arranged in many combinations and permutations to generate a large variety of Gargle types, most of which are very rare. A few Gargle types are more common ("universals") and are usually confined to a particular site. Such a complex dialect pattern is unusual in a call.