How do we study birds in urban settings? A systematic review

Abstract

As the global footprint of urban areas expands, there is increasing motivation to conserve biodiversity in these areas. Cities typically develop in fertile, biodiverse locations, and often contain relatively high numbers of threatened species. Despite this, urban landscapes are often overlooked as conservation priorities. Although birds have been extensively studied in urban areas, research effort may not be consistent among species. An unbalanced representation of species and collective tendencies to focus on particular research topics pose a risk to the completeness of our understanding of urban ornithology. Developing a better understanding of how birds are studied in urban areas is crucial to mitigate the risk of biodiversity loss. Here, we conducted a systematic quantitative literature review to determine research effort at the species level for birds in Australian urban areas. We modelled which species characteristics predict the level of species research effort across studies with varying levels of conservation relevance and study themes. We found that studies with a strong link to conservation were uncommon and that most studies targeted broad suites of species rather than specific groups or species. Species characteristics, including species taxonomic group, migratory behaviour, threat status and body mass, were significant predictors of research effort. These results highlight the biases that exist in urban bird research, showing that applied conservation is uncommon and usually broad. Understanding the biases in Australian urban ornithology establishes a foundation for expected biases on other continents, which once addressed will be beneficial to conserving urban bird biodiversity.