The protection of significant habitats of indigenous fauna is a matter recognised by the Resource Management Act 1991 as one of national importance. The aim of this article is to investigate the nature of the term habitat as applied by the RMA. The context of the enquiry is the natural and physical environment of New Zealand, with a particular focus on habitats of avian fauna. A central question raised by the research, is whether or not air space used by birds can be considered habitat in terms of s 6(c) of the RMA. This issue is of contemporary importance, due to the advent of wind farms to the New Zealand environment. The compass of the term habitat has yet to receive full scrutiny by New Zealand courts and it is timely to give consideration to the nature of habitat. International approaches to habitat are also examined. The article concludes that where a regime such as the RMA prioritises habitat protection as a national goal, a lesser result for indigenous avian species will be achieved, if areas of air space expertly identified as significant to the survival of the species, cannot be defined as constituting significant habitat within the meaning of s 6(c).