Adapting to suburbia: bird ecology on an urban-bushland interface in Perth, Western Australia.

Abstract

Birds in urban landscapes must contend with fragmented and degraded remnants of native vegetation and their survival may be dependent on factors such as their ability to disperse through and/or utilize the urban matrix. We examined the frequency of occurrence of birds in native bushland in Kings Park, Perth, Western Australia, and in nine adjacent suburban gardens. We quantified dispersal capacity by observing bird crossing frequency and height over a major six-lane road separating the bushland from adjacent gardens. Finally we quantified matrix utilisation by recording foraging behaviour in urban gardens and bushland. Native bushland had a higher species richness than urban gardens (30 versus 17 species) and 18 species were associated more strongly with bushland. Of these 18 species, 61% were never recorded in urban gardens. Gardens were typified by three generalist species, the Singing Honeyeater Lichenostomus virescens and the introduced Laughing Dove Spilopelia senegalensis and Spotted Dove S. chinensis. Three generalist species, the Red Wattlebird Anthochaera carunculata, Rainbow Lorikeet Trichoglossus haematodus, and Brown Honeyeater Lichmera indistincta were equally abundant in all habitats. Four of 18 bird species (Singing Honeyeater Red Wattlebird, Rainbow Lorikeet, and Australian Ringneck Barnardius zonarius) accounted for the majority of road crossing events. Urban gardens provided a rich resource for generalists and urban exploiters, all of which spent significantly more time foraging on nectar in gardens and significantly more time foraging on insects in bushland. We conclude that urban gardens provide habitat for some species that exploit nectar, but most species in bushland, particularly insectivores, do not use gardens. Our results indicate the importance of retaining well-managed bushland for supporting viable urban bird populations.