Volunteers vs Norway rats

There has been a significant incursion of Norway rats inside the Sanctuary in the last few months. Following the capture of an adult rat near the campground at the end of May, a series of juveniles was caught there and in the swampy gully nearby and toward Pink Beach. A standard pest incursion response was implemented by ramping up the density and checking of traps and tracking tunnels in this area, resulting in a total catch of 11 in June.

However, when carcasses and new tracks were found farther afield it was decided that the incursion response needed to escalate and every trap and tunnel in the entire sanctuary should be serviced every week, first ensuring that each was stable, clear of vegetation and working properly. A call went out for the regular trappers to help out and for new trappers to come forward, and some full-time trappers were employed as well. While this found a few rats over a still wider area, some in areas of known activity (near the duckpond for example), most further catches have been in the Pink Beach/Campground swamp area. Cameras installed there showed that there was still some activity there at the middle of July.

The capture of juvenile animals suggests that breeding has occurred inside, though it is possible that pregnant female(s) made their way in. To shed some light on this all of the rat captures will have their tail tips DNA-tested to determine relatedness between individuals. Evidently the rats resident in the Whangaparaoa area have a distinctive DNA so the testing will also show whether these caught inside are locals, possibly coming in around the fence, or whether they caught a ride in from further afield. The good news is that catch and print activity has dropped away in the last few weeks and winter is on our side as these animals should not be breeding until spring. In the last three weeks only one rats has been caught so rangers are optimistic that we can win out and continue to provide a safe haven for native wildlife.

Animal pest incursions like this are an ever-present risk, particularly at a site with an open ended peninsula fence and high public visitation. Experience elsewhere shows that invader pests can be managed to low levels, with consequent harm to the wildlife values of the site being minimal. You can help by always checking vehicles and gear for stowaway pests before visiting the park, telling your friends and family about these precautions to keep Shakespear pest free, and reporting any suspected pest activity immediately.