Eradicating rodents from islands is only half the battle. After eradication, it is vital to protect the investment by preventing rodents re-establishing. Preventing rodent invasions can be challenging, and when an invasion is detected managers must respond with the force of a full eradication, but in only hours, and not with the years of planning an eradication can typically afford. In fact rat invasion biology on islands was what started my career in island conservation, during my PhD research, where counter-intuitively I reintroduced rats to rat-free islands intentionally to precisely study their behaviour during reinvasion. It was during this research that we learnt how powerful conservation dogs are as an additional monitoring tool, allowing rapid detection of invading rodents, and with a success rate as high as traps and poison at detecting and preventing invasion.
Yesterday I had the pleasure of working with not one but three trained conservation dogs from the Department of Conservation and Auckland Council Treasure Islands programme. We were out and about on the Hauraki Gulf of New Zealand checking also not one but three islands to confirm the absence of mice following recent eradications. Encouragingly, none of the three rodent detection dogs detected any sign of mice on any of the three islands. This confirms the ongoing mouse-free status of Saddle Island following mouse invasion research there, and with a further year of mouse-free status will enable us to confirm the eradication of mice last year from Motuketekete and Moturekareka. At the same time I was also able to survey the three islands for the presence of returning grey-faced petrel who have just finished their courtship period on the islands and will shortly lay eggs for the 2015 breeding season.
Thanks to Auckland Council for supporting the eradication and monitoring on these islands.