Lizards

Our first night on Puangiangi, 31 April 2012, was frightening. It wasn’t the scary 12-volt electrics, which were way dodgier than anything William Heath Robinson might have concocted, or getting to grips with how the water might be directed to the inside tap, but rather the things that went bump in the night.

That day, we had arrived with the locksmith, gained entry and gotten to understand the infrastructure as best we could in the fading light, eaten and went to bed. Soon enough a lot of thumping and scrabbling came from the ceiling and walls of the house. This was frightening as it could have meant that Peter’s hard work in 1999 to eradicate rats had been undone. It turned out though, that this is possibly what walls and ceilings are meant to sound like on the mainland, if they were full of geckos.

Poking around the following day, we discovered that all the geckos were common geckos (now raukawa gecko, Woodworthia maculata), and that they liked the shed as well as the house. There was not a box or a nook that didn’t house a gecko, or several. Our tools and gear in the shed now need a regular clean lest they disappear beneath piles of sticky gecko droppings. They are also numerous in piles of corrugated iron outside, and Ross Webber’s various mussel-float constructions are popular too. It was a bit of a party trick to show visitors the hundreds of geckos gathered under a corrugated iron stack, but Lynn Adams and I got a shock when a robin showed up and began swallowing not-so-small geckos whole when we lifted the iron.They also get into our various rainwater drums scattered about the island to provide water for birds, and often could not climb out and drowned, until we worked out they needed a length of rope coming out the top of the drums to escape by. Dad was quite taken when he visited by the sight of little gecko faces peering over the edge of the spouting on the house, where they would gather at night probably to get a drink of the dew collecting from the roof. A look on tree trunks at night will show them on their way to catch insects, or take nectar and fruit. We’ve also seen them in the house in the daytime popping up from gaps near the windows to try to grab flies on the glass. At this time of year they are pretty torpid on the cool mornings, and they need careful rescuing if we are opening and closing doors and find them in the cracks. They wake up within a few seconds when given some warmth from a hand, and make a break for it. Peter noted only a few common gecko when he first visited Puangiangi, and the recovery since rat eradication has been explosive.

A sunny day early on soon also revealed glossy brown skink (Oligosoma zelandicum), and northern grass skink (Oligosoma polychroma). These common skinks certainly should be there, but we often remark that numbers seem quite low compared with what we have seen on similar islands, and are also a surprisingly low proportion of the known lizard population. Late summer, however, shows good numbers of young skinks in the grass. Perhaps the adults are more circumspect given the moderate numbers of kingfisher around, or maybe sunny skink habitat is slowly shrinking as the pasture becomes more rank and is taken over by shrublands.

 

What else should be there? Forest gecko would have a similar ability to common gecko to persist in the face of rat predation, and would be expected to recover at the same rate, but so far we have not found any. They are on Maud Island/ Te Hoiere and some of the other Sounds islands, although they were last reported from Takapourewa in 1897. It’s only a few tens of thousands of years since Puangiangi would have been connected to the mainland, so I think they must have been there at some point, if not now.

Marlborough green gecko would be another possibility, although again we haven’t seen any yet. When Sue and I went to Auckland to visit Ross and Jean Webber in 2012, though, Jean said she had seen a green gecko by the island’s house where they sat in 2009-10 contemplating where the interim owner, and their money, might be. Jean is not a lizard expert and I wondered whether she might have seen a dull-greenish common gecko which are, er, common, but when pressed as to the type of green she confidently pointed to a tissue box with an apple-green graphic on the side, the colour of the Marlborough green. They are pretty elusive and who knows if we might corroborate her observation one sunny morning when walking past a kanuka and see one contrasted against the foliage. Other lizards that are nearby and might have a chance of remaining on Puangiangi are striped gecko and spotted and speckled skink. All of these lizards made it into our management plan as candidates for translocation if they were not found in the meantime.

In the 1980s when Peter visited Ross, the party was shown an old photo of a gecko which Ross had kept as a pet. The photo was most likely of a Duvaucel’s gecko. The nearest current population of this threatened species is on Kuru Pongi/ The Trios. Ross was clear in conversation with me that it was the only one of its type on Puangiangi and that he had collected it from a “stack”. Conscious that I might wear out my welcome with my incessant questioning, I wasn’t able to establish for sure that he might have meant, say, North Trio. His reticence might have been because, if he had been allowed pet geckos then, he certainly would not be now without a permit.

When present, Duvaucel’s stand out because of their size and are easy to find after dark when they come out to feed. A careful look around confirmed Ross’ comment that they were very unlikely to be on Puangiangi. I imagine their size and docility would have had them eaten by rats early on if they had been there historically.

Both for our ecological restoration and to assist the species, a Duvaucel’s translocation would make good sense. Peter’s translocation proposal was approved by both Ngati Koata and DOC, and we arranged to visit Kuru Pongi over several nights in early March 2014. Jim Williamson came out from Nelson with Brigadoon and he was to be the ferryman over however many trips it took to get the permitted number of animals. Jim kindly covered all his expenses for his trip and saved us a considerable sum in transport costs.

The weather wasn’t great on the evening of the 3rd, but we made the 7 km trip to Kuru Pongi anyway. Alison Cree in her 2014 book on tuatara quotes Hugo Schauinsland, a museum director from Bremen, who collected in the area with his wife and assisted by George Webber in December 1896 and January 1897, landing on Kuru Pongi- “an undertaking which…could almost have cost me my life”. We were to land on the western side in Jim’s inflatable but just before we were ready to go, a squall blew up. We didn’t want to go one better than Schauinsland and land on the rocks upside down and we were ready to head back to Puangiangi for the night. Luckily though, Jim found a little bay on the northeastern side that was sheltered enough to get to land and that appeared to give access to the top. Peter ferried the catching party ashore in the inflatable and Lynn Adams and Chris Birmingham from DOC, and I, got ourselves and our bins of gear up a tight scree onto the main ridge of the island before nightfall.

The going on Kuru Pongi is very slow, with low, scratchy scrub. On the main ridge there was a hint of a flagged route from earlier parties, of which there have been few, and we found a flat site and sorted out our gear. Lynn gave me and Chris a refresher on how to tell a small Duvaucel’s from a large Common, and males from females (we wanted more females), and we began catching just before dark. Lynn withheld crucial habitat information and established a handy lead in the catch race by grabbing drowsy geckos from under rocks while Chris and I were concentrating on the trees. As it got properly dark we all started to contribute to the steadily growing pile of animals in individual calico bags in their fish bin. The scrub was so impenetrable that there was little point trying to move around much, and we did pretty well by standing still and listening for them moving, and watching for them on the trees. They could be distracted by our head lamps while an unseen hand gathered them up easily without any sudden lunges that might have harmed them or caused them to shed their tails. The island is also home to tuatara and burrowing petrels, and it was nice to see them on their island going about their nightly activities, or inactivities in the case of tuatara.

By midnight it was clear that we could catch the full complement in a single night and so we decided to keep going. By 3:00 we had 51 animals, all with their tails, back at base and Lynn checked each for over-all health, and identity given that I was catching too. We slept for a few hours and dawn revealed that Lynn had ended up uncomfortably close to a drop-off, which two of us found quite amusing. A bit of grunting and heaving got the boxes and us down to the beach and Jim and Peter picked us up at 7:00.

Back on Puangiangi, Peter and Lynn weighed and measured each animal and marked them for future identification using the recommended toe-clipping method. Hugh Blank from Pure Science kindly donated the electronic balance we have for weighing animals. The proportion of females was just right at 70%, but with relatively few gravid, and all were in robust health when examined more closely in daylight. By early afternoon we were able to release them at the chosen site in the northeastern forest. We had chosen a place where there are some solid rock slabs with gecko-sized cracks. They all made for the cracks with little encouragement.

This was a good moment to reflect on the contribution the late Tony Whitaker made to this project. He gave advice to Peter just days before his untimely death, and the techniques we used, and getting the whole thing done in under 24 hours, owe much to his work on lizards over many years. The kohekohe canopy is reasonably high and we won’t stand much chance of seeing them in numbers for a while. We’ve looked for them twice in the intervening months and have seen a single one, sitting quietly on its rock after dark. I don’t want to disturb any of the animals unnecessarily and the geckos don’t benefit from us knowing their every movement, so checking for translocation success will be of the low-impact variety. The obvious threat to them will be if predators get on to the island, and it will remain important to keep weka numbers vanishingly low, although the northeastern forest is not especially favoured by weka as far as we can work out.

To my knowledge, this is the first translocation of any species from Kuru Pongi, possibly save for early “collecting” trips for tuatara where the animals were released into a garden or suchlike, or indeed Ross Webber’s pet gecko.

Lizard diversity would be a good marker of ecosystem health, and we wanted to get some more professional advice on what if any other lizards are and should be there. An expert team of Lynn Adams, Sue Keall (Victoria University), Peter, Rod Hitchmough and Ivan Rogers (both DOC) visited for a week in mid-March 2015, equipped with binoculars with torches taped to them, Gee’s minnow traps and pitfall traps. They confirmed what we thought about the state of common gecko and the two widespread skink species.

One evening Lynn rang me and said they had found something significant, and demanded that I guess. I immediately suggested that they had found spotted skink (Oligosoma lineoocellatum), which turned out to be right and they all thought I was very brainy. Lynn doesn’t know that Peter and I had already considered that spotted skink ought to be there and it was probably just a matter of the people with time and the right identification skills showing up. My reputation won’t be punctured by putting this on the internet because that is a great place to keep secrets. After finding the first spotted skink, the team quickly found more and have concluded that it is at least moderately abundant.

The team did not find any forest gecko, Marlborough green gecko, striped gecko or speckled skink, but noted that ongoing survey effort would be needed to say they were not there for sure. In the meantime, they said we should go ahead and translocate striped gecko, a species found on Te Hoiere and Takapourewa and in need of insurance populations. Peter has completed the first stage of the permit application as of last month.

Title photo, common gecko in a corrugated iron stack. Courtesy Roy Grose.