Composition, seasonal occurrences and habitat use of bird assemblages in wet forests on the Central Plateau ofTasmania

Bird communities in montane wet forest at three sites (altitudes 700,750 and 880 m) on the Central Plateau of Tasmania were surveyed over a 12-month period between December 1991 and November 1992. Monthly transect counts were carried out at each site. Snowf:,lls are common at all three sites during winter and snow can remain at the highest site for several weeks. Bird communities at the study sites showed significant differences in densities and seasonal patterns even though species composition was similar. These differences were influenced by the variation in habitats and the environments at the sites. Butlers Road, the lowest site with the mildest winters and greatest proportion of drier habitat, had the highest bird densities, while D'Arcys Bluff, at the highest altitude, had the lowest. The degree of seasonal changes of birds was similar to mainland montane wet forests, with over half the species moving either locally or to the mainland, However, there was variation in seasonal occurrences between the study sites, with proportionally more species moving from the highest site during the winter, Within the study sites, the wet forest habitats with a diverse shrub and/or fern understorey supported higher bird populations than did mixed forest and damp forest. Species richness is lower at these sites compared with equivalent montane forests on mainland southeastern Australia.