The decline, fall, and rise of a large urban colonising bird

Context

The process of urbanisation results in dramatic landscape changes with long-lasting and sometimes irreversible consequences for the biota as urban sensitive species are eliminated. The Australian brush-turkey (Alectura lathami) is a recent urban colonist despite atypical traits for an urban adapter. Contrary to observed range declines and initial reports of decreased reproductive success in cities, Australian brush-turkeys have increased their range in urban areas.

Aims

Historical atlas and present citizen science data were used to examine the changing distribution of the Australian brush-turkey at continental and city scales, and the changing land use in urban areas occupied by the species. We assess which environmental and landscape features are driving observed distribution changes over time.

Methods

We describe and map changes at the continental scale between 1839–2019. We then assessed colonisation of the cities of Brisbane and Sydney (located 900 km apart) over the period 1960–2019. At the city scale, we quantified the changing land use within Australian brush-turkey occupied areas over time using classification of satellite imagery.

Key results

The Australian brush-turkey’s geographical range has shifted over the last century, with the species receding from the western and southwestern parts of their range, while expanding in the northwest. Areas occupied in the cities of Brisbane and Sydney have expanded, with more recently occupied areas containing less vegetation and more developed land than previously occupied areas.

Conclusions

Our results confirm that Australian brush-turkeys are successfully colonising urban areas, including major cities, and are likely to continue moving into urban areas, despite declines elsewhere in their natural range. The species is not limited to suburbs with a high proportion of greenspace, as Australian brush-turkeys are increasingly occurring in highly developed areas with limited vegetation.

Implications

This study highlights that species which were locally extirpated from urban areas, and thought to be unlikely candidates for recolonisation, can successfully occupy human modified habitats. Successful expansion is likely to be associated with key behavioural traits, urban greening, and legal protection from human persecution.