Cameras spot elusive island predators
Sensor cameras have been used to solve the mystery over why some elusive predators are avoiding the pest traps installed on Otago’s Quarantine Island Kamau Taurua.
After a year of monitoring the pest traps installed on Quarantine Island Kamau Taurua in Otago, locals were perplexed to discover that although mice and rats appeared to be hanging around the traps – the mice even eating the chocolate spread bait – they were not getting caught.
To solve the intriguing mystery, a team of locals tried a different approach as part of a new community-led citizen science project on the reserve.
Dr Jill Hetherington, co-ordinator of the project, says that the study covered two areas: predator control and monitoring biodiversity on the island. It aimed to investigate why dead rats and mice weren’t being found very often at trap sites and also survey plant and animal life so that data can be compared between seasons.
Cameras were introduced to monitor traps, and also tracking tunnels because the team knew that mice and rats were present, says Jill. “Some people were a bit frustrated. They were saying there should be four bodies under there and there is nothing there.”
These students are preparing to put bait (in the jar) onto a tracking card.
Mystery solved by camera footage
The cameras showed that mice were entering traps, eating bait but getting out without activating the trapping mechanism, while rats were sniffing around but not entering the traps. The traps have since been adjusted to catch mice, and trap placement is being reviewed to better attract rats.
The other significant part of the project, monitoring plant and animal diversity on the island, has engaged many schools and adult groups in the community to learn about the wide range of birds on and surrounding Kamau Taurua and look at where seedlings flourished.
For the past two years, people visiting on monthly open days and visiting schools have carried out bird counting at nine sites on Kamau Taurua. It’s the first time that data has been collected on the many bush, paddock and shoreline birds - both native and introduced - who live there.
Tracking tunnels - tubes containing tracking card - were used in monitoring the predators.
Visitors delight in listening for birds
Claire Hagglund, co-ordinator of the bird survey, says visitors learnt about the importance of biodiversity to the island and that many had their first experience of identifying birds by listening and looking.
“To see someone going “oh look at that, that is a bellbird,” and seeing the excitement in their face - that is what I really love about it.”
With only two years of data collected, it’s too early to say if bird populations - and that of the Korimako Bellbird in particular - are increasing, she says. But generally over time native species tend to do better in protected areas, while the populations of introduced species don't change.
The study also monitored lizards using corrugated plastic sheets to draw the lizards out into the open for counting and observation, finding one species, the Southern Grass Skink, present. Data analysis is still underway to determine if the lizard population has been growing.
Corrugated plastic sheets were used to draw out lizards for monitoring.
Academics relish practical citizen science
Jill Hetherington says it was both a highlight and a challenge for academic scientists, who are usually focussed on research and lab work, to engage in community science. “We had to remember we are making an impact. We have people asking questions and going home having achieved and learnt something.”
“It was also satisfying connecting children with nature and the predator control side of it. And some older people are now taking school groups around. Their confidence has grown and it is amazing to watch as well.”
Almost 1000 people visited the island over 12 months, including 15 schools and several adult groups.
“It is very rewarding. No matter what, you walk away with a grin on your face because everyone has had a good time.”
Bird counts and lizard surveys are continuing, and predator data is being applied to a future predator control plan under Predator Free Dunedin, which has funding from Predator Free 2050 for further predator control work.
Tracking cards work by placing bait in the centre of the card, which contains wet ink. The predator eats the bait and then imprints its distinctive footprints on the card as it exits the tracking tunnel.
About the project
This project is run by Quarantine Island Kamau Taurua Community with support from volunteers, staff at Orokonui Eco-Sanctuary and the Otago Participatory Science Platform.
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