Quick Dips

Snooping on Tuatara

A tuatara surveillance project, using a video camera to watch the reptiles in their burrows, has been launched by Tim Markwell, a Victoria University PhD student. The aim of the exercise is to investigate the relationship between the 50,000 tuatara and the hundreds of thousands of birds that live on Stephens Island in Cook Strait.

Scientists think the tuatara take over burrows that have been dug by the birds, mainly fairy prions, rather than excavate their own. Fairy prions are about the size of pigeons, and adult tuatara are able to eat these birds and their eggs, although they are no match for the larger sooty shearwaters that also use the island.

The birds are migratory, so between February and June there are very few birds there, and the tuatara can invade the burrows with impunity. The tuatara live individually in the burrows; the younger ones seem to move around but the older males stay permanently in one burrow.

Markwell has begun poking a small camera, at the end of what looks like a green plastic garden hose, down tuatara burrows. He works mainly at night, using infra-red lights on the camera to illuminate the tuatara homes and monitoring progress through a small screen.

An initial expedition proved that the technology worked, although the camera lens had a very short focal length and and could capture only close-up images -- such as a sooty shearwater chick, annoyed at the intrusion, attacking the camera.