1080 and Bird Repellents
Bird repellents have been demonstrated to deter a range of bird species from ingesting seeds and/or baits and may provide a solution to limit kea by-kill during aerial 1080 poisoning operations. However any repellent which is used to prevent non-target by-kill must not repel the target species, namely rats and possums.
The Kea Conservation Trust in partnership with the Department of Conservation is now in the process of trialling bird repellents to prevent kea ingesting 1080 baits during pest control operations.
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Bird Repellent Trials
The captive trials were completed at the beginning of October. Thanks to the research team;
Tamsin Orr-Walker (KCT), Mel Willmott and Tess McGregor as well as our Science Advisors Dr. Nigel Adams, Dr. Lorne Roberts and Josh Kemp (DoC) Thanks also must go to all the facilities involved:
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Franklin Zoo
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Hamilton Zoo
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Auckland Zoo
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Otorohanga Kiwihouse
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Totara Springs
Tamsin (KCT) checking out Little Girl
after the daily repellent treatments.
Photo credit: Helen Schofield (Franklin Zoo) 2009
The first of the bird repellent trials kicked off at Franklin Zoo in Tuakau (45 minutes south of Auckland just off State Hwy 1) in the first week of August 2009.
As part of the Department of Conservation research permit requirements, the KCT was required to initiate the trials at a facility which had a vet on site. Helen Schofield, Franklin Zoos, co-owner and operator is also the zoo veterinarian and was pleased to be a part of the first trials to prevent kea from eating 1080 pellets in the wild. Franklins efforts will help to prevent more kea deaths in the wild from 1080.
The two kea, Little Girl and Big Boy were intially given food grade cereal pellets (used as pre-feed to encourage rats and possums to take toxic 1080 baits in subsequent aerial drops) over a three day period. Weights of how much the birds consumed during this time were recorded to provide a baseline to compare against repellent impregnated pellets which were given for a further 7 days.
Photo: Helen Schofield - putting out lunch for the kea after the morning trials
Across all facilities, kea were seen to be attracted to the cereal pellets (Wanganui No. 7 used as a prefeed in the wild), however, after presentation of the repellent impregnated pellets, kea across all facilities showed an aversian to the pellets.
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1080 and Kea - the story behind the trials
1080 has been used to control pest populations in New Zealand since the 1950's. Many introduced species such as rats and possums not only damage native plant species but also predate on the eggs and chicks of our native birds, including kea.
Research on the effect of 1080 aerial drops on native species has been undertaken since it was first used. Records of kea deaths have been documented as early as 1964 (Spurr, 1979; 1999) and residue in kea carcasses as early as 1967 (Douglas, 1967). However no specific monitoring of kea has been undertaken until the beginning of 2008.
At the beginning of 2008 DoC radio tagged 18 kea in the Franz North and South areas (on the West Coast of the South Island). 6 birds were found dead, confirmed through ingestion of 1080 poison.
However, a group of 10 radio-tagged birds in the Arawhata area and 2 in the Hohonua Range all survived a previous 1080 drop raising questions as to the differences between drop regimes (timing, use of pre-feed) and kea behaviour in the different areas.
The deaths reported in the Franz/Fox area are one of the highest reported rates of death in any of our native species and constitutes a potentially huge blow for the species. How other populations in 1080 aerial drop areas are affected is unknown and of equal concern.
The Department of Conservation in conjunction with the Kea Conservation Trust are now looking into ways to mitigate inadvertant kea by-kill by trialing bird repellents which remain attractive to the target pest species. Information on this project will be posted as it is received.
Kea eating a 1080 pellet
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Repellent Results
Trials across the six sample groups (5 facilities) were completed during August – October 2009. At no time were kea observed to have an adverse health response to the repellents. Calculation of dry mass consumed across all sample groups, showed a significant negative response to the repellent pellets (refer Figs 1, 2 and 3) and a return to ingestion of pellets during post treatment (Fig 1).
Figure 1. Mean consumption rate by captive Kea of untreated pellets and pellets treated with bird repellent (D-pulegone + anthraquinone and D-pulegone only). Data are from a total of 10 birds across 5 different captive establishments. Error bars are ± 1 standard error.
Ingestion of repellent pellets illicited a primary aversive response behaviours including head shaking and beak wiping directly after ingestion of small amounts of the pellets. Anecdotally kea were observed to have a greater repellent effect (ie no further consumption of pellets) after consuming moderate amounts of repellent laced pellets indicating that they may have been exposed to the effects of the secondary repellent, anthraquinone.
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