- Department of Conservation, 22 Gee Street, Renwick, Marlborough 7204, New Zealand
- Department of Conservation, 69 Cron Street, Franz Josef/Waiau 7856, New Zealand
- Manaaki Whenua Landcare Research, Gerald Street, Lincoln, New Zealand
- Wildlife Surveillance Ltd, Weedons, Christchurch, New Zealand
- Wyndon Aviation Ltd, Maddisons Road, Weedons, Christchurch, New Zealand
- Department of Conservation, Grand Central, 161 Cashel Street, Christchurch 8011, New Zealand
- OSPRI, Level 9, 15 Willeston Street, PO Box 3412, Wellington 6140, New Zealand
- Department of Conservation, 32 River Road, Rangiora 7400, New Zealand
The Nationally Endangered kea (Nestor notabilis) is one of five endemic New Zealand bird species for which non-target mortality from consumption of 1080 (sodium fluoroacetate) pellet baits, used to control invasive mammals, has been recorded. Kea by-kill varies among operations, but reducing predators can deliver population-level benefits that outweigh the risks. Inclusion of bird-specific repellents within the bait matrix is possible, provided that target species (possum (Trichosurus vulpecula) and ship rat (Rattus rattus)) kills remain high. The primary repellent d-pulegone (0.17% wt wt−1) has previously shown potential as a kea repellent with high pest kill efficacy. However, d-pulegone use was precluded by instability in the bait matrix, with a very high rate of degradation causing its concentration to fall below the operational target concentration after manufacture. Recent work has improved the stability and formula of d-pulegone. We used (1) choice trials in which d-pulegone concentrations of 0, 6, 10, and 50% were presented in non-toxic cereal pellets to wild kea at Arthur’s Pass village, and (2) non-choice trials presenting d-pulegone and non-repellent baits to free-ranging wild kea in the alpine zone in mountains surrounding Arthur’s Pass. Overall we found some evidence that d-pulegone-treated baits had a repellent effect to kea; total bait consumption declined with 50% d-pulegone concentration in the choice trials and decreased with 6% and 10% d-pulegone in the alpine trials. Obvious adverse reactions to baits were rarely observed (n < 5). Individual bait consumption quantity was low, especially where repellent was present, suggesting that the inclusion of d-pulegone within 1080 cereal pellets has the potential to reduce non-target risk to kea if used in aerial poisoning operations. We therefore recommend pen trials to test the palatability of these lower concentrations on target mammal species (possums, rats) as a next step.