A perky, upright wren restricted to alpine regions in the South Island of New Zealand. Has a very short tail and rounded wings, but distinctive long legs and toes. Male is a mossy green above and pale gray below, with noticeable yellow flanks and a creamy eyebrow. Female has duller plumage. Stance is often erect; constantly bobs up and down, flicking its wings, before hopping and running. Flies very short distances. Seen out in the open in rocky boulder fields, hence its common New Zealand name of “rock wren.” Gives a high-pitched three-note call which travels well in the open alpine terrain. Pairs will sometimes duet.