The influence of remnant bushland on the composition of suburban bird assemblages in Australia

A large database collated by bird watchers was analysed to determine whether birds living in the urban habitats of Sydney, Australia could be characterised as a discrete community differing from those occupying a variety of nearby native habitats. Standardised surveys at fixed distances from nine remnants of one native habitat (woodland/scrub on Hawkesbury sandstone) were then conducted to determine whether size of, and distance to, remnants of native habitat influenced the composition of the surrounding suburban bird community. Non-metric multidimensional scaling did not separate the bird community of urban parks and gardens from those occupying residential areas. However, analysis of similarity showed that these communities were significantly different from the bird communities of each of the native habitats. Suburban habitats could be differentiated by the prevalence of exotic species as well as parrots, large honeyeaters, and large birds incorporating vertebrate foods in their diet, and a relative rarity of small insectivores and honeyeaters. Nearby remnant vegetation had little effect on the bird community inhabiting suburban areas. No significant effects of remnant size or remnant proximity were detected for species richness, individual abundance or community composition. These results suggest that there is little overlap in use of urban and remnant habitats by the majority of species and that in order to increase bird diversity, urban habitats must provide a fuller complement of ecological requirements.