Habitat use by kiore (Rattus exulans) and Norway rats (R. norvegicus) on Kapiti Island, New Zealand
The continued coexistence of ecologically similar species relies on niche separation in space or time. Four similar species of introduced rodent occur in New Zealand, but the mechanism(s) allowing them to coexist in varying species combinations throughout the country is poorly understood. In order to investigate the coexistence of kiore or Pacific rats (Rattus exulans) and Norway rats (R. norvegicus) on Kapiti Island, rats were kill-trapped in exotic grassland and four forest types between 1992 and 1996.