Sandgrouse

Sandgrouse is the common name for Pteroclidae (Template:IPAc-en), a family of sixteen species of bird, members of the order Pterocliformes<ref name="IOC">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> (Template:IPAc-en). They are traditionally placed in two genera. The two central Asian species are classified as Syrrhaptes and the other fourteen species, from Africa and Asia, are placed in the genus Pterocles. They are ground-dwelling birds restricted to treeless, open country, such as plains, savannahs, and semi-deserts. They are distributed across northern, southern, and eastern Africa, Madagascar, the Middle East, and India through central Asia.Template:Cn The ranges of the black-bellied sandgrouse and the pin-tailed sandgrouse even extend into the Iberian Peninsula and France, and Pallas's sandgrouse occasionally breaks out in large numbers from its normal range in Asia.

Description

Sandgrouse have small, pigeon-like heads and necks and sturdy compact bodies. They range in size from Template:Convert in length and from Template:Convert in weight. Their feathers' colours blend in with their desert environment.<ref>Template:Cite book</ref> The adults are sexually dimorphic with the males being slightly larger and more brightly colored than the females. They have eleven strong primary feathers and long pointed wings, giving them a fast and direct flight. The muscles of the wings are powerful and the birds are capable of rapid take off and sustained flight. In some species, the central feathers in the tail are extended into long points.Template:Cn

The legs are short and members of the genus Syrrhaptes have feathers growing on both the legs and toes, and no hind toes, while members of the genus Pterocles have legs feathered just at the front, no feathers on the toes, and rudimentary hind toes raised off the ground.<ref name=Campbell>Template:Cite book</ref>

The plumage is cryptic, generally being in shades of sandy brown, grey and buff, and variously mottled and barred, enabling the birds to merge into the dusty landscape. There is a dense layer of under down which helps insulate the bird from extremes of heat and cold. The feathers of the belly are specially adapted for absorbing water and retaining it, allowing adults, particularly males, to carry water to chicks that may be many miles away from watering holes.<ref name=EoB>Template:Cite book</ref><ref name=Gooders>Template:Cite book</ref> The amount of water that can be carried in this way is 15 to 20 millilitres (0.5 to 0.7 fluid ounces).<ref name=Creagrus>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>

Distribution

File:Syrrhaptes paradoxus 1.JPG

Pallas's sandgrouse in a field in the Gobi Desert

Members of the genus Syrrhaptes are found in the steppes of central Asia. Their range extends from the Caspian Sea through southern Siberia, Tibet, and Mongolia to northern and central China. They are normally resident, but Pallas's sandgrouse can be locally migratory and very occasionally is irruptive, appearing in areas well outside its normal range. This happened in 1863 and 1888, and a major irruption took place in 1908 when many birds were seen as far afield as Ireland and the United Kingdom where they bred in Yorkshire and Moray.<ref name=Gooders/><ref name=Creagrus/>

Members of the genus Pterocles are mainly found in the drier parts of northern, eastern, and southern Africa, though the range of some species extends into the Middle East and western Asia. The Madagascar sandgrouse is restricted to Madagascar. The black-bellied sandgrouse and the pin-tailed sandgrouse also occur in Spain, Portugal, and southern France. Most species are sedentary though some make local migrations, typically to lower altitudes in winter.<ref name=Creagrus/>

Behaviour and ecology

Diet and feeding

File:Sandgrouse flock.jpg

Namaqua sandgrouse are gregarious and feed and drink in large flocks

Sandgrouse are principally seed eaters. Other food items eaten include green shoots and leaves, bulbs, and berries. Insect food such as ants and termites may also be eaten, especially during the breeding season.<ref name=Campbell/> The diet of many sandgrouse is highly specialised, with the seeds of a small number of plant species being dominant. This may depend on local availability but in other cases it reflects actual selection of favoured seeds over others by the sandgrouse. Seeds of leguminous plants are usually an important part of the diet. In agricultural areas oats and other grain are readily taken. Seeds are either collected from the ground or directly from the plants.

Foraging techniques vary between species that coexist, which reduces competition; in Namibia, double-banded sandgrouse feed slowly and methodically whilst Namaqua sandgrouse feed rapidly, exploring loose soil with their beaks and flicking it away sideways.<ref name=Biodiversity>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> Grit is also swallowed to help grind up food in the gizzard.<ref name=Campbell/>

Sandgrouse are gregarious, feeding in flocks of up to 100 birds. As a consequence of their dry diet, they need to visit water sources regularly. Drinking times vary among the species. Ten species drink at dawn, four at dusk, and two at indeterminate times.<ref name=Campbell/> When drinking, water is sucked into the beak, which is then raised to let the water flow down into the crop. By repeating this procedure rapidly, enough water to last twenty four hours can be swallowed in a few seconds.<ref name=Campbell/> As they travel to water holes, they call to members of their own species and many hundreds or thousands synchronise their arrival at the drinking site despite converging from many different locations scattered over hundreds of square miles (kilometres) of territory.<ref>Template:Cite journal</ref>

They are vulnerable to attack while watering but with a large number of birds milling about, predators find it difficult to select a target bird and are likely to have been spotted before they can get close to the flock.<ref name=Gooders/> The choice of a watering site is influenced by the topography of the nearby ground. The sandgrouse tend to avoid sites with cover for mammalian predators and their greatest risk is usually from predatory birds.<ref>Template:Cite journal</ref>

Sandgrouse travel tens of miles to their traditional water holes and tend to disregard temporary water sources which may appear periodically. This clearly has a survival value, because a dried up water source in an arid region could result in dehydration and death.<ref name=Gooders/> The Burchell's sandgrouse in the Kalahari Desert sometimes travels over Template:Convert daily to reach a water source.<ref name=Creagrus/> Not all species need to drink every day, and the Tibetan sandgrouse does not need to travel to drink, because of the abundance of water from melting snowfields in its habitat.<ref name=Gooders/>

Breeding

File:Painted sandgrouse chick.jpg

Painted sandgrouse chick

Sandgrouse are monogamous. The breeding season usually coincides with a crop of seeds after the local rainy season and at this time the feeding flocks tend to break up into pairs. The nesting site is a slight depression in the ground, sometimes lined with a few pieces of dry foliage. Most typically, three cryptic eggs are laid, though occasionally there may be two or four. The intricately patterned, precocial downy young, and egg colouration (though not shape) closely resemble those of many Charadriiformes. Eggs are near elliptical.<ref name=Hackett/> Incubation duties are shared; in most species, the males incubate at night while the females sit on the eggs during the day. The eggs usually hatch after 20–25 days.

The precocial chicks are covered with down and leave the nest as soon as the last hatchling has dried out. The parents do not provide them with food and they learn, with parental guidance, what is edible and what is not. The chicks obtain their water from the soaked downy feathers on the adults' breasts. Chicks are too small and young to thermoregulate at first, and their parents shade them during the hottest part of the day, and brood them to keep warm at night. The chicks remain with their parents, as a family group, for several months.<ref name=EoB/>

Taxonomy

The Pteroclidae was formerly included in the Galliformes due to the similarities the family shares with the true grouse. However, it was later discovered that these similarities are superficial and a result of convergent evolution.<ref>Template:Cite journal</ref> Sandgrouse were later placed near the Columbiformes largely due to their reported ability to drink by the "sucking" or "pumping" action of peristalsis of the esophagus, an unusual characteristic.<ref name = lorenz>Template:Cite journal</ref> More recently, it has been reported that they cannot suck up water in this way,<ref>Template:Cite journal</ref> and they are now treated separately in the order Pterocliformes. They have been considered near passerine birds, and are thought by some to be closer to the shorebirds (Charadriiformes).<ref name="Grzimek">Template:Cite book</ref>

In the DNA-study by Fain and Houde (2004)<ref>Template:Cite journal</ref> they were included in the Metaves, together with the Columbiformes. In the larger study by Hackett et al. (2008)<ref name=Hackett>Template:Cite journal</ref> they were once again positioned close to the Columbiformes, in Columbimorphae, but also with the Mesites.

Phylogeny

Living Pterocliformes, based on the work by John Boyd.<ref name="Boyd">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>

Species

Sandgrouse
Common and binomial names<ref>Template:Cite book</ref>	Image	Description, range and status	Egg
Pin-tailed sandgrouse Pterocles alchata (Linnaeus, 1766)	File:Pterocles alchata (cropped).jpg	Length Template:Convert There are two subspecies:<ref>{{#invoke:citation/CS1|citation	CitationClass=web }}</ref> P. a. alchata – Spain, Portugal, France, north west Africa P. a. caudacutus – Middle East, Turkey and eastward to Kazakhstan Status: Least concern	File:Ganga cata MHNT.jpg
Double-banded sandgrouse Pterocles bicinctus Temminck, 1815	File:Pterocles bicinctus -Northern Cape, South Africa -male-8.jpg	Length Template:Convert There are three subspecies:<ref>{{#invoke:citation/CS1|citation	CitationClass=web }}</ref> P. b. ansorgei – south west Angola P. b. bicinctus – Namibia, Botswana, north west Cape Province P. b. multicolor – Zambia, Malawi, Mozambique and Transvaal Status: Least concern
Burchell's sandgrouse Pterocles burchelli Sclater, 1922	File:Pterocles burchelli 1.jpg	Length Template:Convert Monotypic<ref>{{#invoke:citation/CS1|citation	CitationClass=web }}</ref> Angola, Namibia, Botswana, Zambia, Zimbabwe, South Africa Status: Least concern
Crowned sandgrouse Pterocles coronatus Lichtenstein, 1823	File:Pterocles coronatus.jpg	citation	CitationClass=web }}</ref> P. c. atratus – Saudi Arabia, Iran, Afghanistan P. c. coronatus – Sahara, Morocco to Red Sea P. c. ladas – Pakistan P. c. saturatus – Oman P. c. vastitas – Sinai, Israel, Jordan Status: Least concern
Black-faced sandgrouse Pterocles decoratus Cabanis, 1868	File:Tanzania 0607 cropped Nevit.jpg	citation	CitationClass=web }}</ref> P. d. decoratus – south east Kenya and east Tanzania P. d. ellenbecki – north east Uganda, north Kenya, Ethiopia, Somalia P. d. loveridgei – west Kenya, west Tanzania Status: Least concern
Chestnut-bellied sandgrouse Pterocles exustus Temminck, 1825 (Pictured on left)	File:Sandgrouse.jpg	citation	CitationClass=web }}</ref> P. e. ellioti – Sudan, Eritrea, north Ethiopia, Somalia P. e. erlangeri – Saudi Arabia, Gulf States, Yemen P. e. exustus – Mauritania to Sudan P. e. floweri – Egypt (almost certainly extinct) P. e. hindustan – south east Iran, Pakistan, India P. e. olivascens – south Ethiopia, Kenya, north Tanzania Status: Least concern
Yellow-throated sandgrouse Pterocles gutturalis Smith, 1836	File:Yellow-throated Sandgrouse Male.jpg	citation	CitationClass=web }}</ref> P. g. gutturalis – south Zambia, Zimbabwe, Botswana, South Africa P. g. saturatior – Ethiopia, Kenya, Tanzania, north Zambia Status: Least concern
Painted sandgrouse Pterocles indicus (Gmelin, 1789)	File:Painted Sandgrouse Male (50325876266).jpg	citation	CitationClass=web }}</ref> India Status: Least concern	File:Pterocles indicus's egg.jpg
Lichtenstein's sandgrouse Pterocles lichtensteinii Temminck, 1825	File:Lichtenstein's sandgrouse Loyangalani.jpg	citation	CitationClass=web }}</ref> P. l. targius – Sahara, Sahel, south Morocco to Chad P. l. lichtensteinii – Israel, Sinai, Egypt, Sudan, Ethiopia, Somalia P. l. sukensis – Sudan, Ethiopia, Kenya P. l. ingramsi – Yemen P. l. arabicus – Saudi Arabia, Iran, Afghanistan, Pakistan Status: Least concern
Namaqua sandgrouse Pterocles namaqua (Gmelin, 1789)	File:Pterocles namaqua -Kalahari-8-4c.jpg	Length Template:Convert Monotypic<ref>{{#invoke:citation/CS1|citation	CitationClass=web }}</ref> Angola, Namibia, Zimbabwe, Botswana, South Africa Status: Least concern
Black-bellied sandgrouse Pterocles orientalis (Linnaeus, 1758)	File:Pterocles orientalis 2018.jpg	Length Template:Convert |There are two subspecies:<ref>{{#invoke:citation/CS1|citation	CitationClass=web }}</ref> P. o. arenarius – Kazakhstan, Pakistan and western China P. o. orientalis – Northwest Africa, Canary Islands, Iberian Peninsula, Cyprus, Middle East, Turkey and Iran Status: Least concern	File:Ganga unibande MHNT.jpg
Madagascar sandgrouse Pterocles personatus Gould, 1843	File:Pterocles-personatus.jpg	citation	CitationClass=web }}</ref> Madagascar Status: Least concern
Four-banded sandgrouse Pterocles quadricinctus (Temminck, 1815)	File:Four-banded sandgrouse (Pterocles quadricinctus) female.jpg	Length Template:Convert Monotypic<ref>{{#invoke:citation/CS1|citation	CitationClass=web }}</ref> Central Africa Status: Least concern	File:Ganga quadribande MHNT.jpg
Spotted sandgrouse Pterocles senegallus (Linnaeus, 1771)	File:Pterocles senegallus 1921.jpg	Length Template:Convert Monotypic<ref>{{#invoke:citation/CS1|citation	CitationClass=web }}</ref> Northern Africa, Middle East and western Asia Status: Least concern	File:Ganga tacheté MHNT.jpg
Tibetan sandgrouse Syrrhaptes tibetanus (Gould, 1850)	File:Tibetan Sandgrouse Syrrhaptes Tibetanus.jpg	Length Template:Convert Monotypic<ref>{{#invoke:citation/CS1|citation	CitationClass=web }}</ref> Mountains of central Asia, Tibet and central China Status: Least concern
Pallas's sandgrouse Syrrhaptes paradoxus (Pallas, 1773)	File:Syrrhaptes paradoxus (Ján Svetlík) (cropped).jpg	Length Template:Convert Monotypic<ref>{{#invoke:citation/CS1|citation	CitationClass=web }}</ref> Mountains and steppes of central Asia Status: Least concern	File:Syrrhapte paradoxal MHNT.jpg

Relations with humans

Sandgrouse have little interaction with people, primarily because most species live in arid unpopulated areas and at low densities. They are not generally sought after as game birds as they are not especially palatable, although they have on occasion been taken in great numbers at water holes. An attempt to introduce them into Nevada failed but they have been introduced to Hawaii.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> No species is considered to be threatened although there have been some localised range contractions, particularly in Europe.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> A subspecies of the chestnut-bellied sandgrouse, P. e. floweri, was last seen in the Nile Valley of Egypt in 1979. It is thought to be extinct, but the reasons for this are unknown.<ref name="Extinct Birds">Template:Cite book</ref>

External links

• Sandgrouse videos on the Internet Bird Collection
• Template:Cite NIE