Aspects of the ecology and behaviour of White-winged Fairy-wrens on Barrow Island

We studied White-winged Fairy-wrens (Malurus leucopterus edouardi) on Barrow Island (20 degrees 43 '5, 115 degrees 28 'E) during September and October 1998. Birds were most abundant (occurring every 1-2 ha of habitat) on ridges in upland areas where Triodia wiseana was the dominant vegetation and was interspersed with open areas. They were less abundant in foredune areas and on red dunes, and were rare in other habitats. Males were significantly larger than females in most morphological measurements. Reproductive males (those with enlarged cloacal protuberances) had significantly shorter tails than non-reproductive males (individuals without cloacal protuberances). Group size averaged 2.4 individuals (Ir = 9; range 2-3) with six of nine groups consisting of just one male and one female. In one of nine groups, the only male present was a completely brown male. Sex ratio of adults in those nine groups was 0.83 (males/females). The display vocalisation was nearly identical in structure to that of birds on the mainland. Three nests were each approximately 0.5 m high in a shrub adjacent to a Triodia angusta plant. In most aspects of their behaviour and ecology, White-winged Fairy-wrens on Barrow Island appear to be almost identical to birds on the mainland.