behaviour has stopped due to low numbers and habitat modification, which also has implications for re-establishment of the species. Prior to 2000, the parrot's population numbered in the hundreds in the South Island, but fell from 500–700 individuals to an estimated 100–200 by 2004, due to significant increases in rat and stoat populations, in particular a rat plague during 2001. The Hawdon River valley houses the largest population, with 70–200 individuals reported in 2013, but numbers are apparently decreasing. The Poulter valley population also declined in 2013, with approximately 40–80 individuals now occurring in this region. The South Branch Hurunui River valley population is even smaller, as few as 20–40 birds. The world population of this species was estimated to be 290–690 individuals in 2013, with translocated island populations making up 160–420 of these birds. Determining exact numbers of the parakeet is difficult, however, due to their rarity, quiet nature, and similarities to C. auriceps. Threats The original decline in population was most likely due to habitat destruction and fragmentation by human activity, hunting, and predation from exotic species. Hunting has ceased and their habitat is protected, but habitat fragmentation may also continue to threaten the orange-fronted parakeet. Orange-fronted parakeets evolved in isolation from land mammals, so are especially vulnerable to introduced predators. Their current decline is due to predation from stoats (Mustela ermine), rats (Rattus spp.), and brushtail possums (Trichosurus vulpecula) which target eggs and nestlings. One population was reduced by 85% in 2001 due to predator irruption after a beech mast (a season of high production by southern beech). Deer and possums also contribute to C. malherbi decline through forest destruction. Competition for food may also be a factor. Introduced birds, mice, wasps, and rats are considerably reducing invertebrate numbers, which the parakeet relies on during winter and spring. The parakeet is however a food generalist and may compensate with other food sources, as observed on Maud Island. This dietary flexibility is promising for species recovery. Inbreeding depression and low genetic diversity may affect the viability of these small populations by reducing their capacity to adapt threats and diseases. The specialised nesting habitat of the orange-fronted parakeet increases its vulnerability to extinction. The reasons for this include: (1) a single nest opening means that incubating females may be unable to escape from invading predators and will also be killed, (2) because only females incubate, predation may cause a