Describes the physical characteristics, usages, and probable functions of 11 vocali- zations of adult Black-capped Chickadees and 2 of the young. Some modifications of the vocal repertoire as compared with other passefines are associated with sociality and hole-nesting. The Fee-bee, usually considered the song of this chickadee, is less complex than some call notes and also has some differences
... [Show full abstract] in function compared to the songs of other passefines. The two most complex calls (Chick-a-dee and Gargle) are associated with social activities. Vocal signals tend toward sexual segregation, which may be important in a monomorphic species. The vocalizations of this species are compared with those of other parids, and selection pressures acting on the structure of vocalizations are discussed. The more complex vocalizations of this species are being