The males weigh on average 13.5 g, whilst the females weigh on average 11.0 g. Brown creepers are about 13 cm in size. Distribution and habitat South of Cook Strait, New Zealand Widely distributed but patchy in forests of the South Island, with some isolated populations persisting in places such as Banks Peninsula, Mt Peel, Hunters Hill and locations throughout Otago. Common on some off shore islands in Fiordland (Secretary, Resolution and Chalky) and Marlborough Sounds (D’Urville, Arapawa and Maud). Widely common on Stewart Island and its surrounding islands (Ulva and North-East Muttonbird). Brown creepers are particularly abundant on Cod Fish Island. Brown creepers inhabit a diverse range of habitats. These include native beech and podocarp forest, exotic plantations as well as willow, gorse and broom, regenerating forest, manuka/kanuka scrub forests, the river flats of the east and the higher altitude mountain/silver beech and red/silver beech forests in the mountains. They will happily live in areas from the sea to the treeline. Their preferred area of the South Island is to the west and north of the Southern Alps as well as Fiordland. The dry scrub forests of Marlborough and Canterbury are also common habitat for brown creepers. When it comes creating nests for raising young, brown creepers prefer dense vegetation up in the canopy of the forest. They drastically declined when Europeans arrived in New Zealand and it is thought that this was caused by the destruction of lowland forest. One would assume that if there were significant enough patches of lowland forest remaining in New Zealand then they would also be found there. Life cycle/Phenology Mating and Breeding behaviors Brown creepers are monogamous and display high rates of mate fidelity. They will usually only change mates if their previous mate dies as opposed to just general mate swapping or divorce. Pairs will strongly defend their territory during the breeding session and to a lesser extent during the rest of the year as well. Pairs will perform duets to maintain and strengthen their bond. In September females will build a nest out of bark, twigs, grass, moss, leaves, leaf skeletons and lichen, all of which is bound together with cobwebs and lined with grasses, feathers and wool. The nest is a deep cup shape and usually takes between 5–17 days to construct. The nest is built in dense canopy vegetation, scrub or low trees between 1m and 10m above