Kea (Nestor notabilis) are highly inquisitive parrots endemic to Aotearoa/New Zealand that often interact with novel items in their environment. To help reduce the risk of by-kill of kea during aerial 1080 pest-control operations, we investigated how kea perceive the different types of cereal baits typically used in such pest control.
One of the criteria for an effective bird repellent in a pest management context in New Zealand is that possum (Trichosurus vulpecula) and ship rat (Rattus rattus) kills remain high where repellents are used in poison baits. Repellents were used in baits applied within different treatment blocks as part of a large aerial 1080 operation in November 2013 near Haast on the West Coast of the South Island of New Zealand.
Aerial poisoning with cereal bait containing 1080 toxin is known to pose a risk to the kea (Nestor notabilis), an endemic New Zealand mountain parrot. For a bird repellent to protect kea during such poisoning operations, it must be effective in bait for 4–12 weeks after the bait is manufactured, as this is when most aerial 1080 cereal operations take place. Two bird repellents have been shown to be effective with captive kea, d-pulegone and 9,10-anthraquinone.
Concern about non-target risks to native birds, particularly kea (Nestor notabilis), from aerial poisoning has prompted the evaluation of potential repellent compounds that could be incorporated into the cereal pellet bait used for possum (Trichosurus vulpecula) and rat (Rattus spp.) control. Initial trials of d-pulegone and anthraquinone were not wholly successful, with the former having poor stability in bait and the latter reducing bait uptake by rats.
North Island robins (Petroica australis longipes) and tomtits (P. macrocephala toitoi) are at risk of being poisoned during pest control operations in New Zealand. Robins are deterred from feeding on diets containing primary repellents (e.g. blue colour, d-pulegone) and secondary repellents (e.g. illness-inducing materials such as anthraquinone, which induce taste aversions). We tested, with wild robins, primary and secondary repellents surface-coated onto dough baits, over 4 days on Tiritiri Matangi Island.