The rock wren is a very small, almost tailless bird that prefers to hop and run on its long legs, and uses its rounded wings to fly only short distances.

Rock wrens, unlike many alpine birds, do not migrate to lower elevations in winter;[5] instead, they seem to shelter and forage in rockfalls beneath the snow layer.

[2] The rock wren is a poor flier, rarely flying more than 2 m off the ground or for distances of more than 30 m. It prefers to hop and run with distinctive bobbing and wing flicks.

[5] Writing in the 1930s,[11] Herbert Guthrie-Smith declared, Xenicus gilviventris, I am glad to think, is one of the species likely to survive changes that from the forester’s and field naturalist’s point of view have desolated New Zealand.

The ravages wrought elsewhere by deer, rabbits, opossums, birds, and other imported vermin are unlikely to affect the welfare of the rock wren.

Even weasels and rats — and I know they ascend to great heights — are hardly likely to draw sufficient recompense in prey from such unpeopled solitudes.… With cover and food supplies unmodified, the rock wren may be considered relatively safe.This was not to be.

Since European settlement in the South Island, rock wrens have become more patchy in their distribution; a study of over 2,100 sightings between 1912 and 2005 showed the area they inhabit had declined significantly since the 1980s.