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Home , Namaqua sandgrouse, Pterocles, Sandgrouse, Spotted sandgrouse, Syrrhaptes, Tibetan sandgrouse

Studies of less familiar IJ6 Pin-tailed I. J. Ferguson-Lees Photographs by Eric Hosking and Carlos Melgarejo Plates 7 2-J 4 The sandgrouse (Pteroclididae) are an African, south Asiatic and marginally European family of 16 in two genera: 14 in and two in (which has no hind toe, feathered feet, and tarsi covered at back as well as front). They are usually placed with the pigeons in the Columbiformes, but this is surely a false relation­ ship suggested by the convergent of anatomical characters and inaccurate observation of behaviour (see later). Indeed, Maclean (1967) has proposed, on behaviour and -albumen studies, that the sandgrouse be included in the , in their own suborder Pterocli close to the Charadrii (waders). They are plump, terrestrial birds with a superficial resemblance to partridges. On the ground their carriage is nearly horizontal (plate 72b) and they walk quite fast with a clumsy waddling gait on short legs. In the air, on the other hand, their rapid flight recalls Golden Plovers Pluvialis apricaria, though their long, pointed wings seem set too far forward owing to the disproportionate silhouette of a small head, a retracted neck and a long or very long tail. Their bodies are cryptically coloured to blend with the arid habitats in which they live, but they tend to have distinctive patterns on the head and under-parts, and the upper-parts barred, spotted, flecked and marbled with olive, yellow, buff, brown, grey, blue, purplish and black. Pallas's Sandgrouse S. paradoxus is the only species ever recorded in Britain, and several were reported in 1969 (Brit. Birds, 62: 452- 453). Two other sandgrouse, the Black-bellied P. orientalis and the Pin-tailed P. alchata, have limited ranges in south-west Europe, however, and the latter is the subject of the photographs on plates 72-74. In Europe the Pin-tailed breeds only in , Spain and the extreme south of . Otherwise its range extends across north from to and across south from the Syrian and Arabian through and to Turkestan and (see Vaurie 1965). The Afro-Asian race P. a. caudacutus is distinguished from the typical form of south-west Europe by paler coloration and broader white edges to the coverts, particularly of females (compare plates 73-74 with 72). Throughout much of its range

533 534 Pin-tailed Sandgrouse studies the Pin-tailed is the commonest sandgrouse, sometimes occurring in vast flocks of several thousands. The species is mostly sedentary, but some wander south in winter, particularly to north-west . The numbers in any area also vary greatly from year to year with avail­ ability of food and water. Vagrants have straggled to , Sicily, Malta and Cyprus, but not north of the breeding range in Europe. Although less bulky than the Black-bellied Sandgrouse, the Pin- tailed is brought to i2| inches by its greatly elongated central tail- (partly visible in plates 72b and 73 a). Its most striking feature otherwise is the pattern of the under-parts, described for the female on plate 72; the male is more brightly coloured with a black patch on the throat in winter (becoming mottled with white in summer) and lacks the thick and rather broken black band down the sides of the neck and across the lower throat. The upper-parts of the two sexes are also very different: whereas the female is barred with yellow and black and flecked with blue-grey (plate 74b gives the best impression) and her wing-coverts are white fringed with black (especially plate 73 a), the male has a grey crown, an orange-yellow face, rich chestnut wing-coverts and a barred rump and tail. His mantle, back and scapulars are mottled olive-yellow in winter, be­ coming more cryptically barred with yellow and black in summer. In having differently coloured upper-parts and throat in winter and summer (though the change from one to the other is not always complete), the male Pin-tailed is unique among sandgrouse. In flight both sexes also show conspicuous white under-wings edged and tipped with black. In general, however, characters are of little value in identifying distant or high-flying sandgrouse and the sounds they make are of more help: fortunately, they call frequently in flight and the Pin-tailed has a particularly loud and distinctive 'catar-catar'. The Pin-tailed Sandgrouse occurs in a wider range of habitats than some of the other species. In Europe it overlaps with the Black- bellied in such semi- areas as stony plateaux and dusty plains, as well as at the edges of cultivation, but it is typically more of a desert in north Africa and south-west Asia. There it is found in a variety of sites from areas of scattered tamarisk, Ketama and other bushes, and patches of wretched cultivation in the dried-out flashes of the winter rains, to the 'hammada' of limestone chips with or without scattered xerophytic plants and other dwarf vege­ tation (plate 74) and totally barren hard-baked clay or flat sand. On the other hand, it also nests around marshes where the receding water has left dried mud and sometimes a good cover of grass and bushy vegetation, as in the Spanish 'marismas' (plate 72). Like most sandgrouse, the Pin-tailed is entirely vegetarian, feeding mainly Pin-tailed Sandgrouse studies 535 on the seeds of chenopods, grasses and other wild plants, and grain, and occasionally taking shoots and green leaves. In some areas it regularly picks seeds from the droppings of camels. It also swallows much grit, quartz and sand: 'sometimes one-third in weight of stomach content' (Meinertzhagen 1964). Although so well adapted to desert conditions, sandgrouse must have regular access to water and this has resulted in the evolution of some remarkable behaviour. First, however, it is neccessary to understand the general pattern of breeding. The winter flocks of Pin-tailed Sandgrouse start to break up in late March and early April, and the gradual separation into pairs continues in May. The start of nesting varies from season to season as a result of tempera­ ture and winter rainfall, and in an early year the first clutches are laid from late (or even mid) April, but the normal peak in north Africa, the and south France is from the second week of May through to late June, though egg-laying continues into August (Guichard 1961, Marchant 1961, 1963, Meinertzhagen 1954, personal observation, etc.). Two broods have been recorded in cap­ tivity (Meade-Waldo 1906), but it is not known whether fresh clutches in July are second broods or replacements (Marchant 1961). Like other sandgrouse, this species is strongly gregarious out of the breeding season and for drinking purposes, and often several pairs nest quite close together in loose groups, but many others are more isolated. Little has been recorded of display postures, but I have twice watched a male following a female, both of them walking de­ liberately with heads held low and tails raised and partly fanned. This seems to be similar to what Maclean (1968) described as 'strutting' in the P. namaqua of southern Africa and which he suggested might be connected with pair formation. The Pin-tailed Sandgrouse nests I have seen have been shallow scrapes 10-12 cm across, 1-4 cm deep and devoid of any lining (plate 73b) apart from wind-blown material. Marchant (1961), however, em­ phasised that 15 out of 23 nests he found were in unaltered hoof- marks, probably all of camels, 'up to three inches or so below the general surface': it proved worthwhile to follow a line of hoof- marks across the desert because 'somewhere along it' he often came across a nest. Even where a sandgrouse makes its own scrape, it does not show the same tendency as many other desert birds to locate it beside a shrub: although some nests may be shaded for part of the day (plate 72a), most are entirely exposed to the full sun (plate 74b). Like all other sandgrouse so far studied, the Pin-tailed seems almost invariably to lay three and, despite the statements of a number of authors (e.g. Meinertzhagen 1954), clutches of two are probably rare in normal conditions. For instance, Marchant (1963) found that 23 out of 24 complete clutches in Iraq had three eggs, although 536 Pin-tailed Sandgrouse studies he also quoted a report from B. L. Sage that all the nests he saw in that country held two eggs, so there may be local variation due to food or climate. All sandgrouse eggs are elliptical and rather shiny, and those of the Pin-tailed vary from stone or pale brown to pinkish, with smears and blotches of dark or reddish brown and underlying grey (plate 73 b); Hue and Etchecopar (1957) gave maximum and minimum measurements of 30 eggs as 50 X 31 mm and 4Z X 29.5 mm. Maclean (1968) found that Namaqua Sandgrouse generally lay at z4-hour intervals and Meade-Waldo (1897) stated that Pin-tailed eggs are laid 'with the interval of a day between each'. Marchant (1961) pointed out that the latter statement is ambiguous, however, and pro­ duced evidence to suggest that there may sometimes be 48 hours between eggs (i.e. a clear day's interval). Eggs seem to be laid in the first half of the day, but not particularly early. The male Namaqua Sandgrouse covers the nest from the first egg until the clutch is complete (Maclean 1968), but in the case of the Pin-tailed Sandgrouse Marchant (1961, 1963) concluded that until the last egg is laid it is the female who broods by day only, though often accompanied by the male. Moreover, Guichard (1961) found that in France the female began incubating with the first egg while the male stood guard at about 100 metres; that she left the nest unattended while feeding and drinking with the male for periods of about half an hour; and that the different stages of development in the three eggs of one clutch suggested a prolonged hatching period. These French observations are completely at variance, however, with those from the Middle East and Africa, and with others on captive birds. In the first place, both sexes of most, if not all, sandgrouse have brood-patches and, once the clutch is complete, they incubate in turns, the female by day and the male by night (Meade-Waldo 1897, 1906, St Quentin 1905, Marchant 1961, Maclean 1968, etc.). In Iraq Marchant found that the female Pin-tailed sits from about 08.00 to 18.00 (ten hours) and the male from around 18.00 to 08.00 (14 hours). Incubation is certainly continuous in hot desert conditions and various authors have suggested that this is necessarv to orevent the ee-s-s from being baked. On the other hand, Bannerman (1959) quoted P. Sushkin's belief that the embryo development of Pallas's Sandgrouse was helped by the sun. Perhaps there are differences according to latitude and temperature, in which case the European race of the Pin-tailed may, as suggested by Guichard's observations, behave rather dif- ferendy. The more cryptic summer plumage of the male Pin-tailed raises the possibility that he may take a greater share by day (see also Meinertzhagen 1954). I know of no such evidence, however, and only rarely in the Middle East does he come near to the nest by day once the clutch is complete (not even the 100 metres of Guichard). Pin-tailed Sandgrouse studies 537 The female Pin-tailed Sandgrouse generally incubates with head low and body flattened (plate 74b), usually facing into the wind. She may raise her head and neck into an upright posture if suspicious and she will sometimes ruffle her feathers (plate 74a) as a comfort movement or flutter her throat as a means of cooling. (Sandgrouse also have thick undercoats of downy bases which may act as a protection against solar radiation.) At least in desert areas she does not normally leave the nest by day unless disturbed. If a man approaches on foot, she usually bobs her head (a common action before running or flying) and then walks or runs from the nest when the intruder is 100-200 yards away, but she may sit very tight when the eggs are near hatching and will allow the approach of a car to within a few yards. Then she may fly up with a loud clatter, accompanied by the male if he is anywhere near, or run off with dragging wings, spread tail and a high-pitched croaking churr. Nest relief does not seem to include any ceremony. Marchant (1961) found that the male alighted 20-300 metres from the nest, that the female flew directly from the eggs when he was still up to 60 metres away, and that he settled on the nest 3-15 minutes later, staying there all night (as Marchant proved once by keeping a continuous watch from his car). In the mornings the female landed 200-300 metres away and then took 6-28 minutes to run to the nest; before departing, the male usually waited at a distance of about one metre until the female was settled. Meade-Waldo (1906) gave the incubation period as 21-23 days for captive Pin-tailed, but, on incomplete evidence from one nest, Marchant (1961) suggested that it might only be 19-20 days in the wild. The eggs hatch on the same day or over a period of 48 hours or more (suggesting variation in the regularity of incubation while the clutch is incomplete) and the adults carry off the shells. The cryptically coloured young leave the nest as soon as they are dry, within 12- 24 hours, and are able to feed themselves from then on; this is very different from young pigeons, of course, nor are young sandgrouse fed or watered by regurgitation as stated by Meinertzhagen (1964). They feed entirely on minute seeds: Maclean found that a week-old Namaqua had 1,400 such seeds in its crop. They seek the shade of shrubs in the heat of the day, but otherwise follow their parents closely at first; often only two survive and each then tends to follow one parent. Apparently they soon become independent, though they still remain loosely with the adults and must rely on the male for water (see later). Maclean found that at three weeks young Namaqua were almost fully feathered and used their wings to balance when running from danger; at four weeks they could fly a few yards and at six weeks they were capable of full flight. Young Pin-tailed can fly 538 Pin-tailed Sandgrouse studies quite strongly when 'feathered and a third to a half grown' (Marchant 1961). During fledging there is an increasing tendency for families to join and adults to flock. In their first autumn young Pin-tailed are mainly yellowish-buff with dark crescentic markings on upper-parts and breast, and the belly is white with a few black bars, but they assume full adult plumage within a few months. So far the importance of water has been mentioned only briefly. Sandgrouse, and their young, must normally drink at least once a day and this is most commonly from one to three hours after sunrise, the times varying somewhat between species. Some may then drink again in the evening from one to two hours before sunset, especially in hot weather. In the breeding season the pattern is set by the incubation behaviour and, again, has been best studied by Maclean (1968) for the Namaqua Sandgrouse. Then the first flights to water in the morning consist largely of females which feed and drink before relieving the males at the nests. The second wave involves chiefly males which afterwards return to the general area of their nests to feed. Follow­ ing a period of inactivity in the heat of the day, the males then feed again before relieving the females who, having been exposed to the full sun for some ten hours, often fly to drink once more before returning to the vicinity of their nests for the night. Sandgrouse flying to water gather in flocks first and are joined by others as they go. Where they are common, therefore, hundreds or even thousands will fly to a large oasis in a steady stream of smaller parties. They are conservative about their drinking sites and become confused if the normal place is unavailable through disturbance, drought or flooding (Meinertzhagen i960). The longest flights to water recorded by Meinertzhagen (1964) were 38 miles 'at a rate of a little over 40 miles an hour' and Maclean (1968) similar recorded Namaqua Sandgrouse travelling up to 40 miles at 45 miles an hour. This maximum of about an hour's flight would thus involve an absence of two hours from the nest area. Sandgrouse call continuously on their way to drink, presumably thereby attracting others to join the flight, but are more silent on the way back. Sandgrouse are often stated to drink like pigeons by sucking or pumping the water up through the immersed bill in one continuous draught (e.g. Meinertzhagen 1964) and this has been one of the reasons for regarding the two families as closely related. It has now been established, however, that at least four species of sandgrouse, includ­ ing Pin-tailed, drink by taking in a short draught and then raising their heads to swallow like most other birds (Cade, Willoughby and Maclean 1966 and personal observation). Sandgrouse usually drink for less than half a minute (often only five to ten seconds) before Pin-tailed Sandgrouse studies 5 39 flying straight up and away, but in that time they take five to 20 or more sips totalling 5-30 ml in the cases of Namaqua and Burchell's Sandgrouse P. burchelli (Cade, Willoughby and Maclean) or up to a 'cup' (about 150 ml) in Black-bellied (see Salt and Zeuthen 1966). The normal morning intake appears to be around 15% of the body weight (Maclean 1968). Sandgrouse seem very vulnerable to predators while drinking (Meinertzhagen 1959, Cade 1965): they are especially alert then, often circling before landing and watching before entering the water, and the whole process is very hurried. The most remarkable part of the drinking behaviour of sandgrouse is their method of supplying the essential water to the young. At the end of the 19th century Meade-Waldo (1896, 1897, 1922) first described how, as soon as the young were out of the nest twelve hours after hatching, the males of captive pairs of Pin-tailed (51 pairs during 1895-1915), Chestnut-bellied P. exustus and Black-bellied Sandgrouse would rub their breasts on the ground until the feathers were awry and then saturate these by standing in their drinking water before running back to the female and young, whereupon the latter would run out and suck the water by running the feathers through their bills—'the appearance being that of a suckling her young'. Meade-Waldo's observations were borne out by St Quentin (1905). Yet for 70 years, although many people saw male sandgrouse wetting their feathers at water holes, it was doubted that water could possibly be carried thus to the young in the wild. Even within the last 15 years Hue and Etchecopar (1957) wrote that 'cette theorie releve du domaine de la fantaisie' and Meinertzhagen (1964) cate­ gorically stated 'that is not so'. In 1960-61, however, Marchant (1961, 1962) watched both Pin- tailed and P. senegallus watering their young thus: the male came back 'flying awkwardly and not with its normal ease. As soon as it landed, it walked to where the chick was with a waddling, open-legged gait and not in the usual manner in which each foot appears to be placed more or less in front of the other'. The chick or chicks would then run to the male who 'stood erect and the young nestled around and below him, with heads inwards, like a litter of suckling puppies'. They remained in this position for one to three minutes during each of four separate observations. Two Pin-tailed broods were 'three-quarters grown and well able to fly'. Then Cade and Maclean (1967) confirmed this behaviour in detail with Namaqua Sandgrouse in the and they also studied the feather soaking of both this species and Burchell's Sand­ . After rubbing the abdominal feathers on the ground, probably to 'de-oil' them, the male squats in the water with feet crossed and rocks his body 'in short, rapid bursts of five to six rocks at intervals 540 Pin-tailed Sandgrouse studies varying from a few seconds to a minute or more'; head and tail are held high and the body is lifted so that only the tips of the feathers touch the water. The soaking process lasts from a few seconds to more than 15 minutes: 'Some individuals .. . appear to be in a kind of dazed or trance-like state, similar to that often seen in sun-bathing or anting birds . . .' Cade and Maclean's description of the behaviour when the male returns to his family is similar to Marchant's, but they were able to see that the young clustering round the male's belly 'take the wet feathers in their , and remove the absorbed water by a "stripping" motion'. Young Namaqua do not themselves fly to water until almost two months old (Maclean 1968) and so this daily process is presumably continued for some four weeks after they take their first flights. Cade and Maclean then studied the structure of the belly feathers, which are slightly curved and unusually long in relation to their breadth. They found that these have specialised barbules whose structure is unlike that recorded for any other species. The barbules on the proximal four-fifths of each feather have no hooks or grooves, but are coiled into spirals terminating in straight hair-like tips. The spirals intertwine to form a network that is 'very resistant to mechanical disruption'. On contact with water, the coiled barbules spring open and project their hairy tips. Water is held 'in this meshwork by interfacial tension, and possibly also by capillarity'. After the water evaporates, the coils spring back to form a strong web. The feathers retained their structure after repeated wetting and stripping with the fingers, whereas belly feathers of other birds and other feathers of sandgrouse quickly became frayed and matted. These specialised belly feathers are a feature of all but one of the 16 species of sand­ grouse, the exception being the high montane S. tibetanus which breeds at 12,000 to 16,000 feet and apparently does not fly to water as regularly as the others; it seemingly has a greater need for insulation than water-carrying and has soft, downy belly feathers. Finally, Cade and Maclean also investigated the water-holding capacity of sandgrouse feathers. The belly feathers of the males of four species were found to hold 15-20 times their own weight (two or three times as much as a paper towel or the corresponding feathers of other birds tested) and those of the females about 11-15 times. The females' feathers have the same structure as the males', but the area of specialised barbules is smaller and thev have a more develooed downy part at the base. In this connection, female sandgrouse do sometimes soak their belly feathers in the same way as the males do and it seems likely that they will occasionally transport water to the Pin-tailed Sandgrouse studies 54i

young, but probably only if the male is dead or injured. A male sandgrouse can hold 25-40 ml of water (about a sixth to a quarter of a cup) in his belly plumage, and, allowing for different rates of evaporation according to temperature and humidity, Cade and Maclean calculated that he should be able to deliver 10-18 gm (= ml) for a distance of 20 miles in the early part of the morning when air tempera­ ture has not yet reached a maximum and humidity is still likely to be high from the night-time effect of cooling and condensation. This dependence on water, and particularly the amount that may effectively be carried to the chicks, must limit the areas in which sandgrouse can nest. In some parts, however, the sinking of wells and bore-holes has probably made extensions of range possible.

REFERENCES BANNERMAN, D. A. 1959. The Birds of the British Isles. Edinburgh and London, vol 8. CADE, T. J. 1965. 'Relations between raptors and columbiform birds at a desert water hole'. Wilson Bull., 77: 340-345. and MACLEAN, G. L. 1967. 'Transport of water by adult sandgrouse to their young'. Condor, 69: 323-343. , WILLOUGHBY, E. J., and MACLEAN, G. L. 1966. 'Drinking behaviour of sandgrouse in the Namid and Kalahari Deserts, Africa'. Auk, 83: 124-126. GUICHARD, G. 1961. 'Note sur la biologie du Ganga cata {Pterocles a. alchata L.). Oiseau, 31: 1-8. HUE, F., and ETCHECOPAR, R. D. 1957. 'Les Pteroclidides'. Oiseau, 27: 35-58. MACLEAN, G. L. 1967. 'Die systematische Stellung der Flughiihner (Pteroclididae)'. /. Orn., 108: 203-217. 1968. 'Field studies on the sandgrouse of the Kalahari Desert'. Living Bird, 7: 209-235. MARCHANT, S. 1961. 'Observations on the breeding of the sandgrouse Pterocles alchata and senegallus'. Bull. Brit. Orn. CI., 81: 134-141. 1962. 'Watering of young in Pterocles alchata'. Bull. Brit. Orn. CI., 82: 123-124. 1963. 'The breeding of some Iraqi birds'. Ibis, 105: 516-557. MEADE-WALDO, E. G. B. 1896. 'The sandgrouse breeding in captivity'. Zoologist, 1896: 298-299. 1897. 'Sandgrouse'. Avic. Mag., 3: 177-180. ——-—• 1906. 'Sandgrouse'. Avic. Mag., new series, 4: 219-222. 1922. 'Sandgrouse'. Bull. Brit. Orn. CI., 42: 69-70. MEINERTZHAGEN, R. 1954. Birds of Arabia. Edinburgh and London, pp. 460-461. 1959- Pirates and Predators. Edinburgh and London, p. 113. i960. ' of sandgrouse'. Ibis, 102: 475. 1964. 'Sandgrouse'. In A New Dictionary of Birds edited by A. Lands- borough Thomson. London, pp.711-712. ST QUENTIN, W. H. 1905. 'The breeding of Pterocles exustus'. Avic. Mag., new series 3: 64-66. "SALT, G. W„ and ZEUTHEN, E. i960. 'The respiratory system'. In Biology and Com­ parative edited by A. J. Marshall. London and New York. pp. 363-409. VAURIE, C. 1965. The Birds of the Palearctic Fauna. London, vol 2: 530-531. PLATE 72. Female Pin-tailed Sandgrouse Pterocles alchata at nest, Spain: compare this dry marshland habitat in the marismas of the Guadalquivir •with the stony desert site in plates 73-74. These photos show well the pattern of the under-parts of the female: white throat, buff surround, black band extending up and round to eye, then succes­ sively a buff band, a thin black line, a broad band of chestnut, another thin black line and, finally, all-white breast and belly (pages 533- 541) {photos: Carlos Melgarejo) PLATE 73. Female Pin-tailed Sandgrouse Ft erodes alchata, and her nest and eggs, , May 1965. This bird has a thinner, more broken neck band and broader white edges to the coverts (page 534). Three is the usual clutch: the eggs are elliptical, glossy, and pinkish-brown with darker markings (page 536) {photos: Eric Hosking) PLATE 74. The same female as in plate 73: above, squatting away from the nest with feathers ruffled as a comfort movement (page 537); below, incubating normally with head down and body flattened. The feathers of the upper-parts are beautifully barred yellow and black, flecked with blue-grey (page 534) {photos: Eric Hosking)