Patterns of avian species richness and assemblage composition may change markedly between and within vegetation types. We compared bird species richness and assemblage composition in cool temperate rainforest and Mountain Ash (Eucalyptus regnans) forest in the Central Highlands of Victoria, south-eastern Australia. We quantified the effects of the age of stands of Mountain Ash on the extent of forest-type differences with cool temperate rainforest. We also explored the influence of the shape of stands of cool temperate rainforest on bird species richness and the composition of the bird assemblage. We found no significant differences in bird species richness between cool temperate rainforests and Mountain Ash forest. This result was consistent with subtle differences in the composition of the bird assemblage, with few bird taxa being totally excluded from either of the two forest types. Some species (e.g. Pink Robin (Petroica rodinogaster)) were significantly more likely to be recorded in cool temperate rainforest but were not uncommon in Mountain Ash forest. We found no evidence of significant effects of stand shape in cool temperate rainforest, which was consistent with analyses of bird assemblages given that most species occurred in both forest types. Hence, we uncovered no evidence of specialist taxa confined to cool temperate rainforest.