Changes in the bird community of Auckland Domain’s urban forest between 1987 and 2020

The Auckland Domain is the city’s oldest park and contains over 70 ha of contiguous, mature urban forest. Five-minute bird counts were made across one year within the domain forest in 2019 and 2020 and compared with counts conducted in 1987 and 1988, using the same methods and at the same survey sites, to investigate changes in the structure of the urban bird community. The abundance and species richness of native and introduced birds increased between the count years and there was structural change within the community driven by increases in the abundance of forest-adapted endemic species, tūī Prosthemadera novaeseelandiae, grey warbler Gerygone igata, and kererū Hemiphaga novaeseelandiae, and declines in generalist native species, silvereye Zosterops lateralis and fantail Rhipidura fuliginosa. Tūī showed the most profound increase in abundance between count years, reflecting regional conservation management of mainland and island forest habitats that benefit this highly mobile species. Increased abundance of eastern rosella Platycercus eximius and common myna Acridotheres tristis also altered community structure between count years, indicative of ongoing colonization by these exotic species in the Auckland region since their introduction to the North Island. The fact that both these species compete with native taxa for nest cavities within forests is of concern. Our results reinforce the need to manage and protect maturing urban forests to enhance native bird populations. Such actions will also support the recovery of native bird populations at a landscape scale.