Before the arrival of humans, 85 - 90 % of New Zealand was covered by forest - a rich habitat for birds. Indeed, New Zealand has been called "the bird capital of the world" prior to being invaded by humans and our companion predator species - dogs, cats, rats and others. Only a very tiny percentage of New Zealand's pre-human-arrival lowland forests remains today. Mäori cleared some areas and Päkehä settlers were responsible for the clearing of the rest.

This loss of forest habitats has had huge impacts on the numbers of species and individual birds as they have lost both their safe sheltering places and their sources of food: leaves, flowers and fruit as well as the invertebrate and reptile species some preyed on. Approximately 30 species of endemic (found only in New Zealand) birds have become extinct since humans first arrived here and many of the species still remaining are present only in quite low numbers and in restricted areas.

Because of introduced pests in the wild, such as stoats, and the loss of native forest due to farming, kerer? are slowly adapting to living in patches of bush near farms, as well as in urban parks and residential gardens.