A Turnaround for Tuatara

Forest and Bird, Issue 313, 1 August 2004, Page 28

A Turnaround for Tuatara

KATHY OMBLER

finds populations of

our ancient reptile are improving, thanks to teamwork.

here’s a cage on Little Barrier Island, that’s teeming with little tuatara. The temporarily caged juveniles represent hope for the future of their species. There are about one hundred of them, all descended from ‘natives’ of the island. None is more than 10 years of age, which is young for this celebrated ‘dinosaur’ of New Zealand reptiles. The tuatara are waiting in their island ‘holding pen’ tended and fed by the resident conservation officer, for the day Little Barrier/Hauturu is declared rodent free. Then it will be deemed safe to let them roam lose on this island ark, free of threats from rats, mice or any other mammalian predator. ‘Releasing over a hundred tuatara on Little Barrier will make a fantastic day, says Charles Daugherty of Victoria University, whose research colleagues Nicky Nelson and Sue Keall can take a fair amount of the credit for getting them all there. ‘It’s a really good outcome, considering 13 years ago they were thought to be extinct on the island and nobody was interested. In fact, the tuatara revival that’s occurred throughout New Zealand, on Hauturu and other islands in the Hauraki Gulf and in the Marlborough Sounds, ranks among our most successful species-recovery stories. It’s one that’s been achieved by cooperation between several organisations; the Department of Conservation, Victoria University, Zoological Society of San Diego, Auckland Zoo, Hamilton Zoo, iwi and conservation groups. It’s seen the establishment of new tuatara populations on several islands. It’s led to the discovery of a new species, the Brothers tuatara, or Gunther's tuatara. Academic research related to the incubation of eggs in captivity has attracted both international

interest and significant sponsorship. Much of the recovery work has been undertaken in line with the Department of Conservation’s Tuatara Recovery Programme, and has been made possible by rat eradications that have ensured the safety of tuatara on island habitats. Charles Daugherty tells this story: ‘Back in 1984, we started a three-year study on tuatara egg ecology. We visited 25 islands and in the process discovered that the Brothers Island tuatara (Gunther's tuatara or Sphenodon guntheri) on North Brother was genetically different, and that it was the only population of that species. We proposed to DoC that they mount a rescue programme by collecting eggs on the island [off

Marlborough Sounds] and incubating them here at Victoria. ‘For three years from 1989 we collected about 70 eggs per year from the island, incubated them here and raised them in captivity. The eggs have a low survival rate in nature so by incubating them here we were able to improve the rate of hatching success. ‘By 1995 half of those hatched and raised were taken to Titi Island in the Marlborough Sounds. In 1998 the rest went to Matiu/Somes Island. Thus we have been able to establish two new wild populations on ratfree islands and rescue what was a very rare species of tuatara’ In the mid-1990s, as rat eradications were carried out on Hauraki Gulf islands, tuatara

recovery attention turned northwards. ‘Populations on some of these islands were hugely reduced by rats, compared with Stephens Island for example where the tuatara density can be as high as 3000 per hectare. On Cuvier, only five very old animals were found. Rats had been eating the eggs and babies.’ ndrew Nelson, native fauna team leader at Auckland Zoo, takes up the tory: "During the island rat eradications the tuatara were caught and held in the zoo for their safety. While here they bred successfully and productivity was very high. We sent the eggs to Victoria University for incubation, then the young babies were returned to our "head start" programme. The youngsters were nurtured at the zoo for the first three to four years, to minimise losses from adult predation. The big "toots" will pretty much eat anything that crosses their paths, including young tuatara. So to give them the best chance of surviving in the wild they were kept here, closely monitored, then released onto their parents’ islands when they weighed about 80 grams and had a 120mm snout-vent measurement. That bigger size minimised potential risk. "To date we have released about 41 animals

through the zoo programme. Last year we released 20 on Cuvier and Stanley islands and we’ve actually now sent back all our animals from Red Mercury Island [off the Coromandel Peninsula] including the adults. ‘We're continuing with the project. What happens is the adults are kept in breeding groups. In March/April we watch for courtship and mating; come September/October we will x-ray the females

to see which are gravid, or carrying eggs. ‘We let them lay their eggs naturally then we recover them and send them to Victoria for incubation. Once the little tuatara have hatched they’re transferred back to our head start programme. Then we work with Waikato DoC staff with island placements. So it’s a real little tuatara kindergarten. ‘We also really push advocacy here at the ZOO, sO with the tuatara we are able to raise

awareness about why they are found only on offshore islands. They are part of our "daily encounter" where we talk about the uniqueness of New Zealand animals. ‘Some of the adults have been here for 14 years now. You definitely get to know them as individuals and see the little life dramas that go on, how they protect their territories, which males are going for which females during breeding. We have in house names; for example, two handsome males from Stanley Island are called Zeus and Dragon. ‘We really enjoy the tuatara programme. It is one of the nice programmes with multiple outcomes. As well as the conservation outcome it provides a good mix of field work, captive, research and advocacy components, and it’s a great little showcase of how different groups are working together to carry out species recovery work. We'll take our lead from the DoC Recovery Group; as long as they are keen for us to help we will keep going. Last year Auckland Zoo provided technical assistance for a translocation of 60 tuatara from the Mercury’s Middle Island to Tiritiri Matangi Island off Auckland. The last sighting of a tuatara there had been in 1902. Graham Ussher, who completed doctoral studies on the recovery of threatened species using tuatara as case studies, was involved in the translocation on behalf of the Supporters of Tiritiri Matangi: ‘After five years of preparation, 60 adult tuatara were captured on Middle Island in the Mercury Group, and released on Tiritiri Matangi in October last year; he says. "We already know that we have two nests on the island and we believe most, if not all, have survived. ‘While tuatara themselves are fascinating creatures, other aspects of this translocation

that interest me are that Tiritiri Matangi has started restoring smaller parts of our wildlife, a refocus from the bird-dominated restoration to date. The translocation has also generated a lot of goodwill between agencies and groups. There has been a whole raft of people involved — DoC (operational requirements), Auckland Zoo (disease screening), Auckland University (research), iwi (support and volunteer involvement) and of course the Supporters of Tiritiri Matangi. or Charles Daugherty, however, Little Barrier is a special story: ‘For years there was a famous old tuatara there and then he disappeared. No others had been seen for

some time and it was thought there were none left. In 1991 DoC gave us permission to search the island. About ten of us spent a week on the island. It was tough work, but we found four animals. The following year four more were captured. In 1994 they started producing eggs; since then all four females have been breeding, producing clutches of eight to 14 eggs every other year. ‘We have been incubating the eggs here at Victoria University with a pretty good success rate, and the young are sent back to the island. Sue Keall and Nicky Nelson have been working at the coal face, along with the DoC staff on the island who are taking care of the young animals. ‘The tuatara are being held on the island with the understanding they will be released when the rats have been eradicated. Little Barrier is ten times bigger than the next largest island with tuatara, the highest island and the only one with a cross section of vegetation that’s found on the mainland. To me, this feels like the biggest success story. Releasing over 100 tuatara on Little Barrier will be a fantastic day? For DoC’s part, the Tuatara Recovery Group leader, Peter Gaze, says the recovery programme has been successful because of effective partnerships with iwi, universities and captive breeding institutions. Looking ahead, he says that while the group continues to focus efforts on keeping tuatara islands free of rats, successes to date now allow the focus to shift towards extending the range of tuatara and facilitating public accessibility and enjoyment.