the mimicry of the lyrebird was "impressionistic" while that of the magpie was "realistic". Australian magpie One hand-raised Australian magpie (Gymnorhina tibicen) developed the ability to mimic human speech, including words and phrases. This individual mimicked a large number of (non-human) sounds, but a third of all mimicked sounds were of human speech. The author stated that mimicry by the magpie was far more accurate than that of the lyrebird. Ducks Musk duck Biziura lobata, a musk duck native to Australia also mimics human speech. Function Several theories have been proposed regarding the function of audible mimicry in general; however, these do not make a specific theory regarding why human speech is mimicked. Several of the theories will apply to only some species due to social structure, habitat and behavioural ecology. Mistaken copying It has been suggested that (general) mimicry of non-bird related sounds is simply a mistaken attempt to copy species-specific calls. Flock recognition In the wild, flocks of parrots develop distinct local dialects. Research indicates they use these to distinguish familiar members of their flock from unfamiliar birds of other flocks. Birds respond more to vocalisations that are familiar to their own, and they ostracize individuals that vocalise in a different way. Birds raised in captivity might mimic humans, particularly their owners, to gain acceptance as a member of the family (flock). If they hear a word or phrase repeatedly, they might interpret that as a vocalisation distinct to their flock. They then attempt to make the vocalisation themselves to maintain their membership of that flock. If the parrot gets no response when it squawks a natural parrot vocalisation, but receives attention or food when it mimics human speech, it has an extra incentive to repeat human words and phrases. Territoriality The territorial song of lyrebirds is relatively simple and substantially different from that of the sounds they mimic—including human speech. Sexual selection for large repertoire One proposed function for (general) mimicry is that mimics have evolved to have a wide repertoire of vocalisations to increase their reproductive success. The male lyrebird, for example, adorns his song with many different mimicked sounds, often the songs of other nearby birds, but can include car horns, chainsaws and barking dogs. Anti-predation General mimicry may help a bird prevent itself or its offspring from being preyed upon. For example, the Australian magpie mimics the call of the barking owl and the