diagnostics
30 cm, 350 g. A large, bulky sandgrouse with a characteristic call. Sexes similar in size, but dimorphic in plumage. Male has yellow throat and supercilium, accentuated by black collar and lores. Chest grey, belly chestnut. Remiges and underwing coverts black. Upperparts grey, washed yellow, with dark sub-terminal marks creating a scaly effect. Wing coverts tinted rufous. Bill pale blue-grey. Eyes dark, surrounded by grey orbital ring. Legs and feet pinkish brown. Female has plain pale yellow face, with dark mottling on nape and crown. Belly chestnut and finely barred black. Upperwings, back and lower chest mottled black, white and brown. Immature similar to female but mottled with finer mottling, plus narrow olive-buff bars on upperwing, back and lower chest (Lloyd 2005).
trophic
The ecology of this species was examined during a long-term study by Blane and Tarboton (1990) and Tarboton et al. (1999) in the Northam-Thabazimbi area. The Yellow-throated Sandgrouse is a monogamous, solitary nester with strong pair bonds (Tarboton et al. 1999). The nest is a scrape or hollow in the ground, sometimes a hoof-print, often partly hidden by a tuft of grass or stubble (de Juana 1997). Nesting pairs appear to be clustered, with up to five nests in a 6 ha field, and some nests may be only 40-45 m apart; conversely, some apparently suitable fields are not occupied (Tarboton et al. 1999). Egg-laying occurs April-October, with a peak in June (Tarboton et al. 1999). A generation length of 5.6 years is provided by BirdLife International (2014). Based on the well-studied Northam population, average productivity is estimated at 0.42-0.85 young/pair/year; mean clutch size is 2.85, and nesting success is 24.8% including clutches accidentally destroyed by ploughing, or 37.9% if ploughing losses are excluded. The daily nest predation rate is 2.55% (Tarboton et al. 1999). The species inhabits flat plains with dark-coloured clay ‘turf' soils that overlie the basic rocks of the Bushveld Igneous Complex, and avoids coarser sandy or rocky soils derived from quartzite, granite and felsites in surrounding areas (Tarboton et al. 1999). The documented preference for plains near swamps and rivers is thus more likely a reflection of the birds' dependence on fine alluvial soils, than the wetlands themselves; birds drink mostly from small stock-watering dams with a bare, flat beach on one side to facilitate easy approach and belly-wetting behaviour (Tarboton et al. 1999). However, before wide-scale habitat transformation through agriculture, the flooding and drying cycles on floodplains may have been important in preventing full plant succession in natural habitats (Tarboton et al. 1999). Within their South African range, Yellow-throated Sandgrouse almost exclusively forage and nest in agricultural landscapes, and especially in fields left fallow for a season or more, allowing for the establishment of pioneer plant communities which provide abundant food resources; seeds of Amaranthus and Crotalaria species appear to be of particular importance (Tarboton et al. 1999). However, if left undisturbed such fields rapidly revert to thornveld savannah, and after about four years become unsuitable for use by sandgrouse. In addition, foraging and nesting also occurs in recently harvested fields, especially of sunflower and soya-bean, and the birds sometimes forage in recently planted or ploughed fields, with the latter often used as night-time roosts (Tarboton et al. 1999).
