About Geophaps plumifera Gould, 1842
The Spinifex pigeon (Geophaps plumifera Gould, 1842) is a small, compact pigeon. Adults weigh 80–110 g (2.8–3.9 oz), have a mean body length of 200–235 mm (7.9–9.3 in), and a wingspan ranging from 300–350 mm (12–14 in). Males are slightly larger than females, and the two sexes are generally hard to tell apart visually. This species has distinctive rufous-brown plumage marked with thin black bars across the wings and back. Its forehead, sides of the crown, and ear coverts are grey, and its bill is black. It has bold, distinctive facial markings: a bright red facial mask is bordered by a black supercilium and a black moustachial stripe. A white band runs from the chin to behind the eye, and the throat is black. A white stripe appears on the breast, and the legs and feet are grey. There is no seasonal variation in this species' plumage. Substantial geographical variation exists in the color of belly plumage, which is reflected in the taxonomic separation of western brown-bellied birds from other recognised subspecies.
Spinifex pigeons are found across most of arid and semi-arid northern and central Australia. They inhabit arid and semi-arid stony habitats including rocky hills, mountainous terrain, gorges, dry rocky creek beds, and nearby gibber plains. The environments they occupy typically experience extreme daytime heat, extreme nighttime cold, large seasonal fluctuations in rainfall, and extended periods of severe drought. This species is most often found in habitats that contain hummock-forming grasses from the Triodia and Plectrachne genera, which are commonly called 'spinifex grasses'. These grasses can form extensive grasslands, and make up the understorey in low open savannah and woodlands of Desert Oak (Allocasuarina decaisneana), eucalypts, and Mulga (Acacia aneura). While the species is strongly associated with spinifex in reported observations, it is rarely seen in spinifex in some areas and prefers other types of sparse grassland instead. It is rarely found near urbanised areas, but does occur in natural habitats used by humans, and has been recorded foraging on food provided to domestic fowl on at least one occasion. Spinifex pigeons do not travel long distances to reach water, so they require permanent water close to their foraging areas. They use both natural and man-made water sources, including waterholes, watercourses, and stock drinking troughs.
Unlike many other desert birds, Spinifex pigeons are sedentary, specialist inhabitants of arid spinifex habitat. They can tolerate extreme environmental conditions; the availability of drought-resistant seed plants in their range varies greatly with seasonal conditions, and often drops substantially during extended drought. They forage on the ground alone, in pairs, or in small flocks, searching for seeds, vegetable matter, and insects. Most foraging happens in bare areas between clumps of grasses, and occasionally in dry rocky watercourses or dry wetland margins. Their diet is made up almost entirely of seeds from drought-resistant grasses and herbs; surprisingly, spinifex is not an important overall food source for the species, as noted by Frith and Barker. Animals and other vegetative material only make up trace amounts of their diet. Spinifex pigeons will also accept some foods provided by humans, particularly around camping areas. Foraging mostly takes place early in the morning and late in the afternoon, during the cooler parts of the day, and close to water sources.
