Identification of nest predators using continuous time-lapse recording in a New Zealand city

Abstract

Predation of eggs and/or chicks is the main cause of nesting failure in birds. Nest predation has been studied in many habitats in New Zealand, but few studies have been conducted in urban ecosystems. Twenty-one nests of four bird species (blackbird [Turdus merula], song thrush [Turdus philomelos], fantail [Rhipidura fuliginosa], and silvereye [Zosterops lateralis]) were monitored over one breeding season in Hamilton using time-lapse recordings. Five predation events were filmed (two by cats [Felis catus], and three by ship rats [Rattus rattus]), 10 nests successfully fledged chicks and 6 nests failed owing to poor weather, desertion, or unknown events. Although the sample size was small, our data suggest that nesting success may be higher in urban Hamilton than in other unmanaged habitats where predation rates can exceed 80%. We recommend that future studies of nesting success in urban birds should also focus on the fates of fledglings, as anecdotal evidence suggested that predation rates may have been highest at this stage.