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Using null model simulations, we tested for non-random patterns of local co-occurrence in 28 congeneric guilds of the Australian avifauna. At the scale of 1 degrees latitude-longitude blocks, species in most guilds co-occurred more often than expected by chance. However, coexistence was significantly less than expected for six of the 28 guilds. In four of these guilds (Climacteris, Cinclosoma, Manorina, and Psophodes), the species were segregated by habitat use and/or geographic range. The remaining two cases were complicated by uncertainty in taxonomy (Malurus) and unreliable field records (Corvus). We also examined distribution patterns in five Australian guilds that are analogs of avian guilds designated by Diamond for the Bismarck Archipelago. For two of the five guilds (Pachycephala and Zosterops), co-occurrence in Australia was less than expected, mirroring an insular pattern of ’’checkerboard distributions’’ in the Bismarck Archipelago. For the remaining three guilds (Ptilonopus, Myzomela, and Lonchura), co-occurrence was significantly greater than expected. Overall, our results suggest that competitive-based assembly rules are not important in determining species coexistence within most congeneric guilds of the Australian avifauna, at least at the large spatial scale of our analysis.