An adult male tuatara at Karori Sanctuary.
Image: Karori Sanctuary

Conservation staff at Wellington’s world-first Karori Sanctuary have found what is almost certainly the first confirmed tuatara nest on mainland New Zealand in over 200 years. The discovery came during routine maintenance work near the Sanctuary’s unique mammal-proof fence, when staff uncovered the four ping-pong ball sized leathery white eggs.
 
‘This time last year we found a gravid (egg-carrying) female’ said Sanctuary Conservation Manager Raewyn Empson.

‘We knew of two suspected nests but didn’t want to disturb them to confirm whether or not they contained eggs. The nest in this photo was uncovered by accident, and is the first concrete proof we have that our tuatara are breeding. It suggests that there may be other nests in the Sanctuary we don’t know of.’

The eggs were immediately covered up again to avoid disturbing their incubation. Although only four eggs were unearthed, it is likely that there are more in the nest – an average clutch contains around ten. The eggs would have been laid almost exactly one year ago in a shallow trench dug by the female and then backfilled.

Tuatara are the only extant members of the Order Sphenodontia and endemic to New Zealand. Every other species in this Order became extinct about 60 million years ago, leading scientists to refer to tuatara as ‘living fossils’.

It is uncertain exactly how long tuatara have been absent from mainland New Zealand but they rare if not extinct by the late 1700s due to egg predation primarily by rats (especially the kiore or Pacific rat). The re-establishment of a population at the rat-free Karori Sanctuary in 2005 was a breakthrough in re-establishing this species in the wild on mainland New Zealand. It has also made the species a lot more visible to the public.