Introduced mammalian predators, such as stoats, cats, and possums, have spread into most of the kea’s range and caused episodic, high mortality events, but invasive control toxins cause lead-poisoning in kea.
Introduced mammalian predators, such as stoats (Mustela erminea), domestic cats (Felis catus), and brushtailed possums (Trichosurus vulpecula) have spread into most of the kea’s range.
Episodic, high mortality events are thought to be associated with plagues of stoats which occur after mast seeding of native beech and rimu. Monitoring by the New Zealand Department of Conservation between 2009-2014 found that only 2% of kea nests in areas without pest control were successful, in contrast with a 27% success rate in areas treated with aerial 1080 in 2015. It is estimated that around 60% of kea nests are normally attacked by predators, especially stoats, which may also kill adults; this can rise to as many as 99% of nests being attacked in a stoat plague.
For the kea to thrive, the control of introduced mammals needs to continue. However, ingestion of lead from building components and the 1080 toxin used in invasive control have potentially widespread impacts on the population. The sources of lead posing a risk to the kea need to be identified, then either removed or replaced with lead-free alternatives or cover to prevent kea access. Kea need to be excluded from predator-control toxins and devices, and the use of risky devices needs to be limited. Efforts to use a bird repellent to deter kea from 1080 toxin have not so far proved effective.