With their robust bodies, small heads, and short legs, sandgrouse can be mistaken for pigeons in silhouette, but their markings are very different beautifully colored and patterned for camouflage in their open, usually arid, habitat.
Most sandgrouse species are cryptically spotted, barred, or streaked: they crouch on the ground to avoid detection, but their long, pointed wings also enable them to make a quick getaway in swift, direct flight, rather like that of a plover. Their plumage is dense; the entire body is covered with a thick undercoat of dark down, and even the base of the bill and the legs are feathered(only in front in Pterocles, all round and down to the toes in Syrrhaptes). This insulates the bird against the temperature extremes of night and midday, winter and summer, and protects the nostrils against windblown sand and dust. The hind toe is lost (Syrrhaptes) or reduced (Pterocles) and the three short front toes are stout and fairly broad for walking on loose sand.
To judge from their feather structure general biology, behavior, and plumage patterns, the sandgrouse appears: to have arisen from a wader (shorebird ancestor, probably from the courses (p18 3). By contrast, the skeleton resembles very closely that of the doves to which they are undoubtedly related, but which arose earlier from the same evolutionary line.
Sandgrouse eats mainly small seeds withal relatively high protein content (in particular those of legumes) and a low water content (less than 10 percent water as a rule). These they pick up by walking with small steps. Pecking frequently with their short bills. The crop of an adult Black-bellied sand-grouse was found to contain about 8, 700indigo plant seeds, while that of a Namaquasandgrouse chick just a few days old con-tainted 1,40o tiny seeds. Sandgrouse takes up grit to help break down the seeds in the gizzard. They feed for most of the daylight hours, resting only in the extreme heat of midday in summer, usually in the shade of a bush.
Sandgrouse needs to drink every 2-3 days, possibly every day in hot weather. Large flocks of hundreds or thousands of birds gather daily at set times (depending on the species) at water holes. Most species drink the morning only, but four are exclusively night-time drinkers (Painted, Lichtenstein’s, Four-banded and Double-banded sand-grouse) and form a subgenus Nyctiperdix, characterized also by barred plumage in both sexes, and bold black-and-white frontal patches in the males.
Sandgrouse may fly up to 8 ohms (5omi)one way to water, though seldom more than 20-30 km (1 2-2 omit). They assemble in ever-increasing numbers near the water, then fly or run to drink quickly, taking about 10 gulps of water, raising the head to swale-low between each gulp. Some species, like Burchell’s sandgrouse of the Kalahari, land right at the water or even on the surface, floating like ducks while drinking, and taking off without effort.
Sandgrouse will not normally drink water with a salt content higher than about 40 percent of that of seawater, since their kidneys are poorly adapted to excreting high salt concentrations. Furthermore, they lack a salt gland, unlike most shorebirds, with which to excrete excess salt. In high temperatures (above about 37°C/99°F) sandgrouse tend to become inactive, seek shade and cease feed-in, drooping their wings and holding their wrists well away from the body to increase heat loss.
Courtship involves head-down, tail-up chasing displays, similar to some threat dies-plays. All species so far studied are mono-famous, but are not very territorial. Northern Hemisphere species breed inspiring and summer, Southern Hemisphere species mainly in winter; but in the Namibian Kalahari deserts of southern Africa times may vary depending at least partly on rainfall.
The female usually incubates by the way and the male at night, though this pattern may be somewhat different in the four members of the subgenus Nycliperdix. The chicks begin to feed on small seeds within a few hours of hatching. Seeds are shown to them by the pecking movements of the female parent. The young can fly little at about four weeks but are provided with water by the male format for at least another, month when they can fly well enough to accompany the parent’s tithe water hole. They attain sexual maturity at about a year.
Non-breeding flocks of thousands of birds are known (such as in Tamaqua sand-grouse), but these are exceptional other than at water holes. Flocks usually number 10-100 birds on their feeding grounds. Sandgrouse is among the favorite prey of raptors, especially the Lanner falcon which hunts mainly at the water holes, as well as of such carnivores as fixes, jackals, and mongooses, to which they are particularly vulnerable when nesting.
Sandgrouse is no longer in great demand for the pot and for sport, as they once were (attempts to introduce them from India and Pakistan into arid regions of these for sporting purposes have failed). Poor agricultural practices, exacerbated by drought, may be increasing the extent of suitable habitat. Combined with the provision of watering places fed by boreholes, conditions for most sandgrouse species have undoubtedly been improved by man’s activities.
See more: HUMMINGBIRDS AND THEIR FLOWERS