New Zealand's Pre-Human Avifauna and Its Vulnerability
In the past 1000 years New Zealand has experienced a major 'extinction event', losing 40-50% of the avifauna, at least 50% of the frog fauna, and unknown proportions of the lizard and invertebrate faunas. During this period, bird species became extinct at different times and rates depending on the particular aspects of their ecology and life history which made them vulnerable to habitat loss, hunting, predation, and competition for food resources. Three groups of species with different levels of vulnerability are recognised within this event: