Rock wren are part of an ancient family of New Zealand wrens. There were once at least seven species in this family, but now only the rock wren and the rifleman remain.
Rock wren are our only true alpine bird. It is unknown how they survive the harsh climate above the tree line all year round, but it is likely they continue to forage on rocky bluffs where snow has not collected and amongst large boulder fields. Some have suggested they may have a period of semi-hibernation.
They build their nests out of snow tussock, moss and line it with many feathers (sometimes hundreds) to keep it well insulated against the cold. The average temperature within a rock wren nest can be as warm as 25–30 degrees, when outside it is below freezing!
A small reclusive bird, rock wrens are poor fliers, nest on the ground and are easy targets for introduced predators.
Rock wren have very large feet and no tail, which makes them excellent rock climbers.
They are largely insectivorous, though they also eat the berries of alpine plants and have been seen drinking the nectar of mountain flax.
Until recently, it was assumed rock wren were relatively safe from predators in their alpine habitat. However, rock wren are now absent or very rarely seen in many areas where they were once commonly found.
Researchers using nest-cameras have identified stoats as the main predator of rock wrens.
Climate change is also anticipated to affect rock wren in the future. As the temperature warms, their alpine environment becomes more suitable for other potential predators, such as rats.
Extreme snow fall events have also caused nest failures in rock wren.
We have been monitoring rock wren nesting success at several alpine locations throughout the South Island within Fiordland, South Westland and Kahurangi National Parks.
In areas where there is predator control, around 85% of nests are successful in fledging young. In areas where there is no predator control, nesting success is 0 – 30% and populations are at risk of extinction.
We are currently developing methods of predator control targeted specifically to protect rock wren. Between 2008 and 2011, 41 rock wren were transferred from the Murchison Mountains, Fiordland to Secretary Island, a largely predator free island with sub-alpine habitat in Fiordland. Rock wren are now breeding well on Secretary Island.
You can help
- Help the New Zealand Alpine Club, Routeburn Dart Wildlife Trust and Friends of the Cobb, who are carrying out predator control in accessible rock wren habitats.
- Report sightings of rock wren to your local DOC office or to NatureWatch NZ.
Help protect New Zealand's native birds
- Volunteer with DOC or other groups to control predators and restore bird habitats.
- Don’t throw rubbish into water ways or storm drains.
- Set traps for stoats or rats on your property. Get more information from your local DOC office.
- Put a bell on your cat's collar, feed it well, and keep it indoors at night.
- Plant a range of native plants that provide food year-round to encourage birds into your garden.
When visiting parks and beaches
- Only take dogs to areas that allow them, and keep your dog under control.
- Prevent the spread of pests. Check your gear for mice and rats when visiting pest-free islands.
- Use available access ways to get to the beach. Stay out of fenced-off areas. Leave nesting shore birds alone.
- Get your dog trained in avian awareness, and help save forest birds like kiwi and weka.
- Follow the water care code. Keep water craft speed to 5 knots within 200 metres of the shore.