From the Introduction to the report on the 2008 Winter Survey:
Little is known of the current population status of Kea in the wild ... Numbers have dramatically reduced over the past 100 years with over 150,000 estimated killed in a legal bounty system until partial protection was granted in 1971 and full protection in 1986 (Temple, 1978 ). The most recent estimate of overall population size indicate numbers as low as 1000-5000 individuals remaining (Anderson, 1986) or as high as 15,000 (Bond and Diamond, 1992; Jackson, 1960). Both figures are widely regarded as estimates only and have been recognised in the latter study to be potentially unreliable (Bond and Diamond, 1992).
Reported in Stuff 2012:
The kea population stood at between 1000 and 5000 but research on four separate populations indicated numbers were decreasing. (NB: this figure is probably a repeat of the 1986 estimate, not a current estimate)
While the actual number of birds in the wild was unknown, Ms Orr-Walker said people frequently said they weren't seeing as many kea as they had in the past.
Threats to Kea:
Continued threats include predation of nests by introduced pest species (particularly possums and stoats) and human impacts (inclusive of lead poisoning). Potential threats include introduction of exotic avian diseases (such as avian malaria) and the unknown effects of global warming on New Zealands alpine habitat.