Cyanoramphus forbesi

The Chatham parakeet (Cyanoramphus forbesi), also known as Forbes' parakeet, is a rare parakeet endemic to the Chatham Islands group, New Zealand. This parakeet is one of New Zealand’s rarest birds and is classified as Vulnerable on the IUCN Red List, as a result of a range of threats to the species survival, including habitat loss, predation, and hybridization. A number of conservation methods have been employed to assist the recovery of this species, and currently the population trend is considered stable. Forbes’ parakeet is one of ten species in the genus Cyanoramphus, a genus consisting of parakeets from New Zealand and surrounding islands. Originally classified as a distinct species (Cyanoramphus forbesi) Forbes’ parakeet was later thought to be a subspecies of the Yellow-crowned Parakeet Cyanoramphus auriceps and was renamed Cyanoramphus auriceps forbesi. Forbes’ Parakeet has since been the subject of a range of molecular tests to determine the correct classification of the bird. These tests have resulted in C. forbesi being reinstated as a separate species to C. auriceps, on the basis of genetic variations, as well as morphological differences such as size and vocalisations. Mitochondrial DNA analysis has also indicated a high degree of hybridisation between Forbes’ parakeet and the Chatham Island Red-crowned Parakeet (Cyanoramphus novaezelandiae chathamensis), which is also found on Mangere Island in the Chatham Islands. Forbes’ parakeet is found only on Mangere and Little Mangere (Tapuaenuku) Islands in the Chatham Islands group. The Chatham Islands are sovereign land of New Zealand, and lay to the South-east of Wellington Historically, Forbes’ parakeet was documented in the 1800s to have travelled to nearby Pitt Island and southern Chatham Island. The species was extinct on Mangere Island by 1930 as a result of significant deforestation. However, the species persisted on Little Mangere Island, until recolonizing Mangere Island in the 1960s after the removal of introduced species (such as cats, rabbits and grazing livestock) and after the native vegetation had a chance to grow back. The parakeet is found in dense forest and scrub, and utilizes tree hollows and rock crevices to nest. Forbes’ parakeet has faced a number of threats to its survival, with the population once falling as low as 20–30 individuals. These threats include deforestation and habitat destruction, the introduction of predators, and the fact that the entire population is confined to two small islands in the Chatham Islands group-Mangere and Little Mangere Islands, which are only 112ha and 16ha respectively. Massive deforestation of Mangere Island has had a significant impact on the population of Forbes’ parakeet, as the environmental boundaries (like differing habitat preference) that once separated Forbes’ parakeet from the Chatham Island Red-crowned parakeet were no longer in place. Deforestation and the creation of open farmland meant Forbes’ parakeet was being deprived of the forest habitat it prefers. As the Chatham Island Red-crowned parakeet was better able to adapt to these new changes in habitat than Forbes’ parakeet, they were able to colonize new areas of the island, including habitat that was previously only occupied by Forbes’ parakeet. As a result, competition for habitat and breeding resources (such as mates) has driven the increased rate of hybridisation between these two species, effectively affecting the genetic makeup of the population of both of these Cyanoramphus species. This is particularly threatening to the C. forbesi population as it is not found anywhere else and therefore runs the risk of essentially being bred out as a species.