Oneroa Rat Trial Results
The Oneroa rat trial ran from 1st May to 13th October 2023. 1670 bait stations were deployed in a 25m x 25 m grid. After 10 weeks no bait was being taken from bait stations, so monitoring devices were deployed, including trail cameras, chew cards, and wax blocks. Subsequently, there were a few rat detections made each week and so the original trial was extended by 6 weeks (the trial was originally scheduled to finish on September 1st).
During the trial extension, additional techniques were used to catch the last elusive rats; these included scent lures and an alternative bait. In week 25 (the final week of the trial extension) there were zero rat detections.
During the Oneroa trial, the team carried out a huge 40,000 bait station services (cleaned and rebaited) and checked monitoring devices 25,000 times.
Oneroa was chosen for the rat trial because of its unique make-up of highly concentrated residential, hospitality, and holiday home properties. Learning what is needed to remove rats from such areas will be critical to the success of an island-wide rat eradication. There is much known in New Zealand about eradicating rats in rural, bush, and forested areas, but there is relatively little known about eradicating rats from urban environments.
Key Learnings from the Oneroa Trial:
The three key questions for the trial were effectively answered:
1. Can bait stations be used to remove all rats from complex areas which include hospitality and holiday homes?
Yes, but different bait and lures could be needed to encourage the last rats to go into the bait stations.
2. Will all sectors of the community support the project?
Yes, community support was fantastic with over 96% of residents in the trial area agreeing to host a bait station, and a lot of positive feedback throughout.
3. Will we be able to acquire all necessary permits and consents?
Yes, these were all obtained. Holiday homeowners were sometimes difficult to get hold of to obtain permissions, but persistence was key.
There were also a number of additional valuable insights:
Environmental factors must be considered, including housing density, waterways & vegetation.
Wet weather impacts the attractiveness of bait and could be a factor in an increased overall rat abundance.
Rats are complex creatures and catching the last 10% takes 90% of the work.
Scent lures seemed the most effective method of attracting the last wary rats into bait stations.