The gargle, a complex call of the Black-capped Chickadee (Parus atricapillus), was studied during the flocking period at two feeders in southeastern Wisconsin. Gargles are usually associated with aggression and are given more frequently by males than females, the gargler almost always winning the encounter. Dominant birds give gargles more frequently than subordinates. Particular gargle types (unique syllable combinations) are not addressed to specific individuals. Birds have at least 13 gargle types in their repertoires, some having over 30, although the total repertoire size could not be determined. Dominants did not have larger or more diverse repertoires, nor did they show differences as compared with subordinates in the amount of sharing of gargle types. Most gargle types are shared, but each individual has some very rare ones that may not be shared. The frequency with which particular gargle types are uttered varies from year to year at the same feeder and also in different parts of the winter. The frequency of occurrence of particular gargle types indicates that selection may favor call-sharing. At two feeders, 383 m distant, which we studied for 2 years, no flock specific dialects were detected, but in one of the 2 years birds visiting the same feeder tended to share gargle types more with each other than with those at the other feeder. Birds that had strong proximity associations with each other, however, did not show stronger sharing compared to those that were more weakly associated.