Te Papa vertebrate curator Dr Colin Miskelly recently led a team that visited Takapourewa / Stephens Island Nature Reserve, to select and gather up 100 fairy prion chicks to move to Mana Island near Wellington. This is the second in a series of blogs about the project and the wildlife of Takapourewa.
Takapourewa is best known as the home of New Zealand’s largest tuatara population, but it holds a rich diversity of other wildlife, including seven other reptile species. Unlike the tuatara (which is not a lizard), all the seven other species are lizards, comprised of four skinks and three geckos.
Tuatara, all four skinks and one of the geckos are frequently found inside bird burrows, and so we often encountered them while searching for fairy prion chicks. The entire island is riddled with fairy prion burrows, and tuatara and raukawa geckos are similarly found all over the island. In contrast, the six other lizard species have narrower habitat preferences, and some are much harder to find.
All seven lizard species have long been recognised as being present on Takapourewa. However, rapid developments in genetic research (in particular) have resulted in most species being considered as members of species complexes (groups of similar-looking, closely related species), requiring new names to allow lizard scientists to label each newly identified entity. Some of this work is still in progress, and so further name changes are likely.
The two largest skink species are currently known as the speckled skink (Oligosoma infrapunctatum) and the spotted skink (O. lineoocellatum). Both are members of diverse species complexes, and it is likely that the Takapourewa forms of both will require different names. Spotted skinks were common among the grassland where we searched for fairy prions, while speckled skinks were most often seen in the low shrub-forest, wherever the sun hit the forest floor. Speckled skinks from Takapourewa were translocated to Maud and Mana Islands in 2004.
The two smaller skink species (northern grass skink O. polychroma, and glossy brown skink O. zelandicum) had a similar habitat segregation, with the glossy brown skinks in damper forested areas, and northern grass skinks abundant in the rank grassland that was grazed by sheep until about a decade ago. Both species occur in the southern North Island and the northern South Island, including the Marlborough Sounds.
The raukawa gecko (Woodworthia maculata) was formerly known as the common gecko – but that ‘common’ name is now known to have concealed at least ten species, some of which are decidedly not common. Raukawa geckos are active by night, but many retreat into bird burrows during daylight.
The southern striped gecko (Toropuku stephensi) is a rare nocturnal gecko, most often found among vegetation a metre or so off the ground at night. The same species elsewhere is known only from Maud Island in the Marlborough Sounds, but a related species (the northern striped gecko) occurs on the Coromandel Peninsula.
The third gecko species on Takapourewa is the day-active Marlborough green gecko (Naultinus manukanus). They are well camouflaged among the shrub and vine leaves where they live, and are certainly more abundant than the 3-4 sightings that we made would indicate. Marlborough green geckos from Takapourewa have been introduced to nearby Wakaterepapanui and Puangiangi Islands after these islands were cleared of rats.
Tuatara mainly eat medium and large insects, e.g. beetles and weta, but will eat larger prey items at times. Fairy prions are hugely abundant on Takapourewa, with an estimated 1.8 million pairs attempting to raise a single chick each year. The eggs hatch in early December, with chicks departing the island in late January through to early February. The growing chicks provide a bountiful food supply for the larger tuatara (particularly adult males), which consume small downy chicks in burrows, and pursue and catch fledgling prions on the forest floor at night.
Takapourewa Nature Reserve is co-managed by Ngati Koata and the Department of Conservation. We thank both for permission to visit and to undertake the fairy prion translocation project.
Related blogs
A box of fluffy birds – moving fairy prions from Takapourewa / Stephens Island to Mana Island
Birds and mammals of Takapourewa / Stephens Island
Insects of Takapourewa / Stephens Island
Nukuwaiata / Inner Chetwode Island – 1936 and 2011 – In the footsteps of Edgar Stead (Part 2)
Critters of Titi Island Nature Reserve, Marlborough Sounds
Really interesting to see these geckos and skinks. I’m impressed that they stay still long enough for you to photograph them! I’d really like to read a similar blog about the lizards of Mana Island now, to help me with identifying them next time I’m there, or will I find some of the same ones?
Hi Gillian
Thanks very much for your comments. I probably do have enough information and images to write about Mana Island lizards, so will give that idea some thought.
There are ten species on the island, of which six occurred there naturally, and four have been introduced (or re-introduced) as part of the ecological restoration programme. Of these, only four are known from the vicinity of the seabird restoration site where the fairy prion team were working. The two seen most often there are the super-abundant raukawa gecko (formerly known as common gecko), and the fast-moving, sun-loving northern grass skink (formerly known as common skink). Copper skinks rarely emerge into sunlight, but can be found inside damp burrows (particularly the older ones used up to 2004). Very occasionally a glossy brown skink is found in these old burrows, but you need to know what to look for to pick it out from the similar-looking northern grass skinks and copper skinks.
Copper skinks do not occur south of Cook Strait, and so are absent on Takapourewa.
The six remaining species are mainly found more than a kilometre from where you were working, although occasional goldstripe geckos have been found on flax at night within a few hundred metres of the site. They are easier to find near the buildings and around Waikoko wetland.
Cheers
Colin
A great story Colin. I’m impressed with you finding all species as well as getting such good images – given that you were really there to do bird stuff!
Pete
Thanks Pete
You know the island, its wildlife and our work programme too well! Yes, it would have been a challenge to find and photograph all seven lizard species in the limited time we had.
I saw six of them during our four-day stay, and photographed five species. I did not knowingly see a glossy brown skink, but they may have been among the many small skinks that scuttled out of our way on sunny days.
To illustrate the two smaller skink species, I used photographs taken on previous visits to islands in the outer Marlborough Sounds. The glossy brown skink image was from Titi Island, and the northern grass skink image was from North Brother Island.
I did manage to get a few shots of speckled skinks, but the image that I chose to use in the blog was taken on Takapourewa in 2004 when we were catching speckled skinks to translocate to Mana and Maud Islands.
Cheers
Colin
Far too honest!