Saving Private Gecko

By: Roger Grove

A year ago, 80 Duvaucel’s geckos were reintroduced to the Tāwharanui Open Sanctuary after more than a century of being absent from the mainland due to the impact of introduced predators. This reintroduction was achieved due to the breeding and research programme being led by Dr Manuela Barry, from Massey University, with the support of the Becroft Foundation who provided TOSSI with funding. Many of you will have read about it at the time.  You would, therefore, know that they grow up to 30 centimetres long, weigh up to 120 grams, live up to 50 years old and that they give birth to just two live young each year.

What you may not be aware of is what has been happening since then.

We are actively monitoring the geckos and mice, and attempting to control the mouse population. The plan is to monitor the impact mice have on the native gecko population over a 10 year period. The research is being led by Massey University, but TOSSI volunteers have an important role to play. Monitoring is carried out every two months over a two-week period.  It involves setting out tracking cards near the sites where the geckos were released.  These cards are checked over the next two days and again a week later.  We are looking for the tracks of mice, skinks and, of course, Duvaucel’s geckos. Duvaucel’s prints indicate the gecko movements in relation to the release sites. A couple of the released geckos were gravid (scientist speak for pregnant).  We had a great find during the last survey when baby gecko footprints were found.  That, of course, is fantastic news. The best part is knowing that the young have survived being killed by predators since being born last summer. The monitoring is carried out by a team of Massey University and TOSSI volunteers negotiating a mix of terrain. There is lots of activity being recorded at many of the release sites, and in surrounding areas.

Duvaucel’s Gecko have a new home at the Tāwharanui Open Sanctuary. Photo: Shaun Lee.

Every six months, recapture of released geckos is attempted. Each gecko has a unique skin pattern allowing any movement from the release site to be recorded. In addition to monitoring, mouse control work is carried out monthly. This involves checking and replenishing bait stations, with the amount of bait taken being recorded. The geckos’ success at survival in the presence of mice will be monitored for the next decade. The data collected will be useful to future reintroductions of Duvaucel’s geckos and similarly vulnerable species.

The reintroduction of Duvaucel’s geckos to Tāwharanui Open Sanctuary is an ongoing project.  We are in the early stages.  Let’s hope the baby footprints are a sign of success now and for the future.

Roger Grove, TOSSI


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