Stoat density, diet and survival compared between alpine grassland and beech forest habitats

摘要: In New Zealand, alpine grasslands occur above the treeline of beech forest. Historically stoat control paradigms in Zealand's montane natural areas have assumed grassland is a marginal habitat that limits dispersal between forest populations. We compared summer-to-autumn (January-April) density, weight, diet and winter survival stoats these two habitats during years low seedfall. Stoats were live-trapped, marked released low-altitude Borland Valley, Fiordland National Park, 2003 2004, caught euthanased for necropsy 2005. Stoat density was estimated using spatially explicit capture-recapture (SECR). The proportion one year but recaptured next used as measure 'observed survival'. Prey remains identified from scats collected 2004 stomachs killed similar both over years, about per square kilometre. Observed 2003-2004 also similar, 2004-2005 higher than 2003, male on average heavier forest, although weights other years. Diet differed significantly habitats, with eating mainly ground weta (a large invertebrate) (72%) hares (23%), while ate birds (31%) mice (19%). Collectively results suggest are not poor quality stoats. Traditionally it has been thought cannot survive invertebrate prey alone. This research demonstrates relying largely can at densities equivalent to vertebrate prey.