TIPPECANOE AUDUBON SOCIETY BIRD COUNT DATA

Abstract of presentation at Indiana Academy of Science annual meeting, 11 Oct 02

Diversity and community structure in Audubon bird count data. David J. Hicks*, Biology Department, Manchester College, North Manchester, IN 46962

The Tippecanoe Audubon Society has collected bird count data in Kosciusko County, IN, since 1975. Sampling is done in late December-early January (Christmas count) and in early May. From 1975 to 2001, 239 species have been observed, 120 in May only, 19 in the Christmas count only, and 100 in both counts. At both times of year, assemblages of terrestrial and aquatic species differed significantly in community structure, with terrestrial assemblages having higher diversity, lower dominance, and smaller-bodied species. Terrestrial assemblages also showed a much more stronger core-satellite organization (24% of species seen in every count, vs. only 8% for aquatic species). For both terrestrial and aquatic assemblages, diversity was greater and body sizes smaller in the May count. Sampling effort varied over the years for the May count, and effort was correlated with numbers of individuals and species recorded. This sampling artifact indicates that Audubon data sets should be used with caution when assessing diversity levels. With selection of data from years with adequate samples, the data are appropriate for assessment of trends in species abundance. Long-term data sets are useful in education, and these data are available (Excel files) at http://www.manchester.edu/Users/Facstaff/DJHicks/index.htm.