Long-term changes over 40 years in the avifauna of an urban reserve: Birrarung Park, Melbourne, Australia

Context Long-term studies are extraordinarily valuable yet are scarce. They provide important insights into changes in the status of species and communities, and responses to land use and environmental change. Aims (1) To document long-term observations on the birds of Birrarung Park, Melbourne, Australia, from 1985 to 2024; (2) to describe changes in the bird community over 40 years; and (3) to identify factors associated with changes through time. Methods Bird surveys (n = 805) were carried out opportunistically to record species and numbers observed. We collated records for species over time and examined long-term changes in species richness and community composition. Key results In total, 153 species were recorded, many of which (35%) were detected in <1% of surveys. Species richness of native terrestrial birds first increased (~1985–2000), associated with revegetation of the Park, and then declined. Small birds (<55 g) showed a marked decline in richness from 2004, coinciding with establishment of the Noisy Miner Manorina melanocephala. Wetland-associated species displayed fluctuations through time, linked to patterns of rainfall, flooding and wetland persistence. Richness of introduced species showed a long-term decline. Conclusions The avifauna of Birrarung Park is dynamic with changes driven by multiple factors. Scarce and vagrant species comprise a large part of the long-term avifauna, reflecting the mobility of birds and the potential for such areas to serve as refuges in the wider urban landscape. Implications Larger urban parks, especially those connected along river systems, have high conservation value. Long-term studies provide critical insight into ongoing changes that otherwise may not be appreciated.