Habitat-of-origin predicts degree of adaptation in urban tolerant birds

Urban exploiters and adapters are often coalesced under a term of convenience as ‘urban tolerant’. This useful but simplistic characterisation masks a more nuanced interplay between and within assemblages of birds that are more or less well adapted to a range of urban habitats. Furthermore, cues are generally sought in behavioural ecology and physiology for the degree to which particular bird species are predisposed to urban living. The data in this paper are focused on two assemblages characterised as urban exploiters and suburban adapters from Melbourne, Australia. This study departs from the approach taken in many others of similar kind in that urban bird assemblages that form the basis of the work were identified at the landscape scale and from direct data analyses rather than indirect inference. Further, this paper employs a paired, partitioned analysis of exploiter and adapter preferences for points along the urban-rural gradient that seeks to decompose the overall trend into diagnosable parts for each assemblage. In the present paper I test the hypotheses that the distinct urban exploiter and suburban adapter assemblages within the broad urban tolerant grouping in Melbourne vary in their responses within the larger group to predictor variables, and that the most explanatory predictor variables vary between the two assemblages. In the end, habitat-of-origin better predicts degree of adaptation amongst urban tolerant birds.