SUMMARYHarrison, C. J. O. 1976. Some aspects of adaption and evolution in Australian fan-tailed flycatchers. Emu 76: 115–119.In the genusRhipidura, the typical fan-tailed flycatchers such as the Grey FantailR. fuliginosaare arboreal and the erected and fanned tail appears to be used for scaring insects into flight so that they can be captured. The Willie WagtailR. leucophrysshows terrestrial adaptations. Vertical tail-fanning is replaced by wing-flashing and some characters of plumage-pattern, voice and nesting may be related to the more open habitat used by the species. Osteologically its leg-bones are longer and its pelvis slightly longer and narrower, which may be correlated with its terrestrial habits. The Northern FantailR. rufiventrisis a more sluggish arboreal species, capturing insects in short flights from a perch and lacking the tail-erecting behaviour. Its leg-bones are short relative to those of the Grey Fantail, but similar in proportion to those of some monarchine flycatchers, and this may be correlated with more sedentary behaviour. These behavioural differences linked with morphological divergence may justify the re-use, as subgeneric or generic divisions, of the namesLeucocircafor the Willie Wagtail andSetosurafor the Northern Fantail and related species. The Willie Wagtail probably evolved in Australia in a refuge area with a more open habitat but the Northern Fantail probably evolved in forests of the New Guinean region.