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Range DescriptionApteryx owenii occurred in forested areas throughout New Zealand prior to European settlement, but is now restricted to seven offshore islands to which it has been introduced, and one mainland site where it has been reintroduced (H. A. Robertson in litt. 1999). The stronghold is Kapiti Island (20 km2), where birds are believed to have been introduced in the early 1900s. In the 1980s, birds were released on Red Mercury (2 km2), Hen (5 km2) and Long Islands (2 km2), and to Tiritiri Matangi Island (2 km2) in 1993 and 1995 (Colbourne and Robertson 1997). Recently birds have also been released on Motuihe Island in 2009 (Anon. 2009) and Chalky Island in 2008 and 2009 (Edmonds 2010). The population was estimated at 1,500 individuals in 2008 (Holzapfel et al. 2008), with 1,200 on Kapiti and 300 spread amongst the other populations. This is an increase from 2000, when the population was estimated at 1,150 individuals (2000) (Robertson and Colbourne 2004). On Kapiti the species is considered to be at carrying capacity and annual survivorship is estimated at 97.5% (Robertson and Colbourne 2004). This population is being used to increase populations on other islands or to establish new populations (Holzapfel et al. 2008). At the same time more recently established populations are increasing.