Trials confirm chevron skinks thriving in Glenfern

Scientific research undertaken in Glenfern Sanctuary suggests that rat control in the sanctuary is benefiting the nationally endangered chevron skink.

Chevron skinks inside Glenfern in general have better body condition and no direct evidence of predator attack compared to those discovered outside the study area. There is also relatively more juvenile and sub-adult skinks inside the sanctuary when compared to outside, which suggests a recovering population. This is great news and a significant achievement for one of New Zealand’s largest and rarest lizards.

children welcoming robins

Chevron Skink


Two months ago Ben Barr of Massey University installed four 9ha grids of 50m x 50m tracking tunnels and traps, two in Glenfern and two in the adjacent Department of Conservation estate. This is part of his masters programme looking at the impacts of rats on chevron skinks.

This month the 56 tunnels (and 98traps) in Glenfern and 56 tunnels (and 98 traps) in DoC estate were baited with peanut butter for 6 consecutive nights. No rat or mice tracks were found in any of the tunnels in Glenfern and almost every tunnel outside Glenfern had multiple rat tracks. The rat traps were baited for 4 consecutive nights. In total, 88 rats were caught in the DoC estate while only one rat was caught in Glenfern sanctuary.

Now that the gates and culvert screens have been closed on the pest fence, we are confident that these low rat densities bode well for the future of our chevron skinks, and also our robins in this year when we will not be rat baiting inside the fence. There should be no incursion of rats to add to the sparse resident population inside the fence.

We have ascertained that Glenfern Sanctuary is a significant hotspot for chevron skinks, and the predator control work undertaken to date seems to be playing a role in this. There is no stronghold for chevrons where they are completely free of predators unlike other endangered species. A successful eradication of pests inside Glenfern Sanctuary should see greater recruitment into the adult population over the next 5 years, and we expect to create a healthy and robust population.

More importantly, an eradication of pests will see Glenfern Sanctuary graduate from being a chevron hotspot, to a chevron stronghold… indeed the only one in the world, and one that is desperately needed for this fascinating and charismatic species.

Tony Bouzaid