Kakapo Codfish / Whenua Hou and Anchor, where they are closely monitored, and Little Barrier / Hauturu Island is being trialled as a third home for the species. The common English name "kakapo" comes from the Māori "kākāpō", from "kākā" ("parrot") + "pō" ("night"); the name is both singular and plural. "Kākāpō" is increasingly written in New Zealand English with the macrons that indicate long vowels. The kakapo was originally described by English ornithologist George Robert Gray in 1845 and named "Strigops habroptilus". Its generic name "Strigops" is derived from the Ancient Greek "strix", genitive "strigos" "owl", and "ops" "face", while
Flightless bird free to increase in abundance until the population was limited by food and territory. A study looking at energy conservation and the evolution of flightlessness hypothesized intraspecific competition selected for a reduced individual energy expenditure, which is achieved by the loss of flight. Some flightless varieties of island birds are closely related to flying varieties, implying flight is a significant biological cost. Flight is the most costly type of locomotion exemplified in the natural world. The energy expenditure required for flight increases proportionally with body size, which is often why flightlessness coincides with body mass. By reducing large pectoral muscles