The Interaction of Bird Communities With Vegetation and Season in Brisbane Forest Park

Abstract

Vegetative and seasonal influences on bird community structure in woodland and open forest in Brisbane Forest Park were examined over two years. The transition from woodland to open forest with open or closed understorey was associated with changes from bird assemblages (or guilds) dominated by nectarivores, vertebrate feeders, ground seed-feeders and invertebrate feeders at all levels, to ones dominated by frugivores and invertebrate feeders from shrubs and dense understoreys. Understorey vegetation density and eucalypt tree height correlated with the presence of understorey invertebrate foragers and frugivores, the latter related to fruit-producing rainforest plants in the understorey. Invertebrate feeders at all levels and ground seedeaters predominated in summer movements into the park. The number of species feeding on bark invertebrates increased in winter. A severe drought in the first year affected most guilds except ground, bark or air invertebrate feeders and ground seed feeders. Vegetation density, structure and diversity and seasonal variation in food sources all influenced the structure of the bird communities.