SEASONAL CHANGES IN BLACK-CAPPED CHICKADEE (POECILE ATRICAPILLUS) SOCIAL STRUCTURE AND GARGLE VOCALIZATIONS

Many organisms form social groups for many different reasons. Individuals within a group gain benefits from having a way of effectively communicating with their group, especially in organisms that maintain their social affiliations for long periods of time. In birds, vocalizations are the main means of communicating among individuals. When there are multiple groups of birds in an area, each group could share vocalizations. This sharing can then create local dialects. Black-capped chickadees (Poecile atricapillus) are small songbirds of temperate habitats of North America that group together in larger flocks every winter. Dialects of the gargle vocalization have been identified that differ between chickadee populations. I tested the hypothesis that gargle dialects exist between black-capped chickadee flocks. I used radio-frequency identification (RFID) technology to assess the social structure of a color-banded population of chickadees in Marquette, Michigan. I recorded gargle vocalizations from the chickadees and used discriminant analysis to determine whether flocks could be distinguished based on their gargle vocalizations. I found significant social structure within the population that matches the behavioral ecology of chickadees. I did not find gargle dialects between flocks, but there was evidence that larger scale changes in gargle vocalizations occurred in the study area