Effectiveness of the bird repellents anthraquinone and d-pulegone on an endemic New Zealand parrot, the kea (Nestor notabilis)

Bird-repellent effects on bait efficacy for control of invasive mammal pests

“…To address these issues, a set of feeding trials was designed using captive wild possums and ship rats to compare acceptability, palatability and kill efficacy of cereal pellet bait with and without the incorporation of anthraquinone and d‐pulegone. The concentrations of repellents used in the feeding trials were mostly similar to those used by Orr‐Walker et al , except for an upper limit of 0.25% anthraquinone, above which the hazard classification for currently registered poison bait for possums and rats would have changed. Use of an anthraquinone concentration above 0.25% would have resulted in a lengthy approval process for repellent poison bait, and, as such, bait would not be covered by the existing approval for 1080 cereal bait.…”

“…The selection of anthraquinone and d‐pulegone for testing against kea was influenced by the requirement that the repellents not reduce the efficacy of bait for possum and rat control . Orr‐Walker et al suggested that was the case, but our closer examination of the unpublished trials on which they largely based that conclusion found that feeding of rats, but not possums, appeared to be reduced at anthraquinone concentrations above 0.04–0.08% (Day TD et al , unpublished, 2000; Clapperton BK et al , unpublished, 2005). However, these previous trials used mostly surface‐coated carrot bait, whereas cereal pellet baits are more commonly used when both possums and rats are targeted.…”

“…The kea ( Nestor notabilis ), a South Island endemic alpine parrot, is one such species, with a conservation status recently upgraded to nationally endangered . By‐kill of kea has been a concern for some time, and this has prompted research into bird repellents that could be added to bait for possum and rat control to further minimise non‐target risks …”

“…A sequential combination of d‐pulegone (a primary repellent, which acts through unpleasant taste or smell or irritant properties) and anthraquinone (a secondary repellent which causes a mild but unpleasant physiological response soon after ingestion) mixed into prefeed cereal pellet bait significantly reduced the amount of bait eaten by captive kea . Secondary repellents are generally more effective when paired with a primary repellent, and the proposed strategy for field use was to have both repellents in prefeed and d‐pulegone in poison bait . Both anthraquinone and d‐pulegone are effective repellents for reducing bird impacts on a range of crops, and anthraquinone also proved effective in reducing the risk of non‐target bird consumption of a poison bait for rodents …”

Visual and taste cues for minimising native bird interactions with toxic 1080 baits – a review of current practices

“…At the moment it is unclear if the cues provided by current prefeed bait (undyed, cinnamon) are sufficient for the development of learned avoidance should secondary repellent be included in prefeed, or if the efficacy of the learned response could be improved with different cues. Some learning of pellet-associated cues was demonstrated by captive native kea, which ate less pellet bait with cinnamon pre-exposure to similar pellets containing anthraquinone and/ or d-pulegone than post-exposure (Orr-Walker et al 2012). However, relative to plain wheat, the amount of blue-dyed wheat with anthraquinone eaten by sparrows was not further reduced by the addition of cinnamon, suggesting little role for cinnamon as a learning cue (Clapperton et al 2012).…”