bright red facial mask is bordered by a black supercilium and moustachial stripe. A white band extends from the chin to behind the eye and the throat is black. A white stripe is present on the breast, and the legs and feet are grey. There is no seasonal variation in plumage. There is substantial geographical variation in the colour of the plumage on the belly, which is reflected in the separation of the western brown-bellied birds from the other subspecies recognised. Distribution and habitat The spinifex pigeon occurs throughout much of arid and semiarid northern and central Australia. It lives in arid and semi-arid stony habitats on rocky hills and mountainous terrain, gorges, dry rocky creek beds and nearby gibber plains. It occupies environments which often experience extreme heat during the day, extreme cold during the night, high seasonal fluctuations in rainfall, and extended periods of severe drought. This species is most often encountered in habitats containing hummock forming grasses of the Triodia and Plectrachne genera, which are colloquially referred to as ‘spinifex grasses’. These grasses may form extensive areas of grassland in comprise the understorey component of low open savannah and woodlands of Desert Oak (Allocasuarina decaisneana), Eucalypts and Mulga (Acacia aneura). Although strong associations with spinifex are reported, in some areas it is rarely sighted in spinifex and prefers other types of sparse grassland. Presence around urbanised areas is rare, however does occur in natural habitats occupied by humans and is reported to have foraged on food provided to domestic fowl on at least one occasion. Spinifex pigeons do not travel long distances to water, requiring permanent water in close proximity to foraging areas. Both natural and man-made water sources are exploited including waterholes and watercourses and stock drinking troughs. Behaviour This species is considered gregarious and sedentary, restricted to habitats within a few kilometres of permanent supply of surface water. They are most often found in pairs or small groups of between four and twenty birds, however, on a rare occasion, have been recorded in a large flock conservatively estimated to number four hundred birds. They are more frequently observed congregating around water sources in small groups for drinking prior to and during the hottest parts of the day around mid-morning and noon. Congregations of larger groups occur during favourable seasonal conditions, with dispersal during less favourable conditions or when numbers build up in good seasons. Flocks