New Zealand’s original forested landscape has been greatly fragmented since human arrival, limiting connectivity and habitat quality for forest-dependent fauna. We review the limited available information about forest bird movement behaviour, especially whole-year sociality and movement, natal dispersal, and pasture- and water-gap crossing. Most small insectivores (17 species) and North Island kōkako are territorial year-round, but frugivore-nectivores (three species), raptors (two species), and volant parrots (four species) can be highly mobile, presumably to find scattered food.
The advent of mammal-resistant fences has allowed multi-species eradications of mammals from ecosanctuaries on the New Zealand mainland. However, maintaining eradication of house mice (Mus musculus) has proven difficult, and at some fenced reserves they are the only exotic mammal present and reach a high population density. Over 5 years we examined the impacts of mice alone on biodiversity at Sanctuary Mountain Maungatautari by comparing forest blocks with relatively high and low numbers of mice.