robins look similar to each other, although newly independent juveniles may not yet have the more lightly coloured breast patch. However, male North Island robins are almost black with a white spot just above the beak, as well as the greyish-white lower breast. Females and juveniles are greyer with more variable pale patches on their breasts and throats. Male South Island robins are dark grey, except for the distinct yellowish-white lower chest, while females and juveniles are again lighter grey with a less distinct breast. Finally, Stewart Island robins look similar to North Island robins (both males and females). New Zealand robins are relatively long-lived; life-spans of at least 14 years have been recorded in the wild. Distribution Historically, the South Island robin inhabited much of the lowland of New Zealand's South Island, but its distribution has become much more patchy in the last century due to habitat loss and introduced predation. There are two populations on the east coast of the South Island, and they are slightly more common in the north and west. It has fared slightly better than the Stewart Island robin, which has been relegated to 3 subpopulations, all of which are in Leptospermum swamp scrubland—although this is not their preferred habitat, it is less heavily populated by mammalian predators. Total population was lower than 500 individuals at one point. A programme of translocation to predator-free islands (such as Ulva Island, Motuara Island, and Nukuwaiata Island) was instituted and proved relatively successful at establishing new populations (around 600 individuals on Motuara alone). In the South Island, P. australis has a strong affinity for Douglas fir plantations, instead of the native forests (kanuka trees) or Monterey pine plantations. This is apparently due to forest structure rather than strict food availability or viable nesting sites, as the species prefers structurally simple forests with dense, even canopies, and ground covered with leaf litter. When the population was introduced to Ulva Island, nesting was positively correlated with the presence of broad-leaved coastal vegetation. Behaviour and ecology Breeding South Island robins are genetically monogamous, and extra-pair paternity is rare. As they do typically remain monogamous, are non-migratory, and remain on their breeding territories year-round, a male and female in one territory will compete for food resources during non-breeding times. Competition is reduced somewhat by slightly different foraging methods; however, they will steal from their mate's cache if given the opportunity. Males