Annual variation in bird numbers across Kaipatiki, Auckland

Abstract

ABSTRACT Birds are good indicators of ecosystem health. Monitoring populations can provide useful information to inform conservation action. Kaipatiki, Auckland, contains approximately 450 ha of indigenous forest, scrub and wetland ecosystems. Pest-controlled reserves are important for supporting avian biodiversity, however, this has not been measured extensively over time across Kaipatiki. An established method to measure changes in avian biodiversity and numbers over time is using stationary point-counts. Using this method, bird counts were conducted in 19 reserves during three consecutive breeding season periods (2016–2018). We also conducted correlative analyses on mammalian predator and bird abundance within Kaipatiki to examine these relationships. Mixed modelling statistical analyses suggested significantly higher numbers of individual birds of all detected species in 2018 than both 2016 and 2017. Tūī, silvereye, grey warbler and fantail were the most common native species observed. Further, rat relative abundance had a significant negative relationship with bird abundance. Ongoing bird counts across Kaipatiki will help provide robust long-term data allowing reliable analyses of population trends and avian species dynamics. These data should be subjected to correlative analyses alongside mammalian predator control data in each reserve. This will enable us to gauge predator control effectiveness in terms of native bird number changes.