Large-scale bird-movement patterns evident in eastern Australian atlas data

Ad hoc studies of the compositions of bird communities at dispersed sites and bird-banding data have failed to reveal the timing, destinations and movement patterns of most Australian migratory bird species. The analysis of national atlas and count data, on the other hand, has the potential to provide information on the species undertaking migratory movements, the timing of these movements, and their sources and destinations. This study examines atlas data of 407 species for evidence of movements by these species in eastern Australia. Atlas and bird-count data were brought together to form the most extensive collection of bird observations in Australia. Mathematical, statistical and graphical tools were used to examine these data for evidence of temporal changes in the spatial distributions of each species. Examples are provided of the application of these tools to four speices (Dollarbird, Eurystomus orientalis, Noisy Miner, Manorina melanocephala, Grey Fantail, Rhipidura fuliginosa and the Budgerigar, Melopsittacus undulatus) that exhibit varying movement patterns. A standardised analysis applying these indicators across 407 species found strong evidence of migratory movements for 101 of these species and suggestive evidence for a further 45 species. These results indicated 19 distinctive patterns of migration among the birds of eastern Australia.