Target threatened species: Rock wren / pīwauwau and Kea – Endangered
Key focus areas of the Southern Alps include; Lake Castalia, Lake Lucidus (north branch of the Wilkin), the Crucible Basin, Gillespie Pass and associated basins. ABT’s rock wren transect monitoring commenced during the 2017/2018 survey season for the north branch of the Wilkin and the Crucible basin featured below.
Rock wren Xenicus gilviventris is New Zealand’s only true alpine species belonging to the ancient family of eight endemic New Zealand wrens of which only two now survive. The rock wren occupies a unique ecological niche remaining above the bush line within alpine basins throughout its life cycle, nesting within rock and vegetation crevices close to the ground.
Often noted flitting between rocks and boulder fields, bouncing up and down on those long legs whilst flicking its wings. Invertebrates such as moths, flies, their larvae, spiders and the fruit of Comprosma species sustain the diet of this alpine passerine.
Similar to most New Zealand endemic birds, rock wren are particularly at risk from predation by invasive introduced mammalian predators mainly stoat now know to be present and impacting rock wren fledgling success within the alpine environment.