The birds were among 12 kea monitored by the Kea Conservation Trust with six birds confirmed alive since the Department of Conservation (DOC) aerial 1080 predator control operation on 11 February.
DOC Threats Director Amber Bill says it’s regretful to lose any kea to 1080 but overall, aerial predator control is proven to benefit kea populations.
“It’s upsetting and disappointing to lose six kea but we are confident with effective control of rats and stoats we will significantly boost nesting success and the number of young birds entering the population.
“We are concerned the tracked kea may have learnt to eat human food around the tramping huts, making them more likely to try 1080 cereal bait.
“DOC’s extensive research of kea through aerial 1080 operations show the risk of 1080 to kea in remote areas is very low but increases markedly with birds that have learnt to scrounge for human food.”
The Matukituki operation followed DOC’s best practice to mitigate risks to kea from 1080 and ensure they benefit from stoat control after last year’s extreme forest mast or seeding.
“We are constantly working to improve our risk mitigation standards for kea, which are informed by our ongoing research programme,” says Amber Bill.
“In light of this incident we will be investing more to explore potential additional measures that DOC can take to reduce the risk to kea in future 1080 predator control operations.”
DOC is also scoping social science research to inform a behavior-change campaign to discourage people feeding kea and prevent kea from learning to scrounge.
“Kea are super smart and present unique conservation challenges. We need to continue to learn and assess all options to protect this national taonga from predators and other threats.”
Recent rodent monitoring results from the Matukituki show rats have been reduced from damaging levels (present in 47% of tracking tunnels) to being undetectable (0% of tracking tunnels), following the 1080 operation. Stoat monitoring is underway.
Part of DOC’s Tiakina Ngā Manu programme, predator control in the Matukituki aimed to protect rock wren/pīwauwau, kea and whio, as well as kākāriki, kākā, and South Island robin/toutouwai from a beech mast-fueled rat and stoat plague. DOC is monitoring whio and rock wren to track how these species are doing.
DOC worked with the Kea Conservation Trust to recover the dead kea (three adult males, one adult female, one juvenile male and one juvenile female), which were sent to Massey University for post-mortem and Maanaki Whenua Landcare Research for toxicology testing.
DOC’s published research on kea survival through aerial 1080 operations used results from 222 monitoring cases involving 205 individual kea. These birds were tracked through 19 aerial 1080 operations at 12 South Island sites between 2008 and 2016 to model kea survival. Overall, there were 24 kea deaths all within six of the 19 aerial 1080 operations and only three deaths out of 110 monitored kea at remote sites.
The Kea Conservation Trust’s kea monitoring in the Matukituki was not designed to measure risk to kea from 1080. The kea sample was not randomly selected across the valleys and more than half the birds were caught around huts. The loss of six out of 12 birds is concerning but we can’t infer impact on the kea population in these valleys from this result.
Only about 10% of kea nests are successful without predator control following a mast year when rat and stoat numbers soar. After predator control about 70% of kea nest are successful and produce at least one chick.
Previous aerial 1080 operations in the Matukituki in 2014 and 2017 were successful in reducing rodent and stoat numbers to very low levels.