Determining the requirements for active management of different elements In New Zealand avifauna can only proceed if those species which are vulnerable to extinction are known. An approach for establishing criteria to assess species vulnerability to extinction that uses population biology, genetics, and modelling is outlined. These criteria also provide a classification of New Zealand birds and a framework for further research. Some initial criteria are drawn up, further development that is necessary of these criteria are discussed, and an overall model for management is proposed.