British Birds - Volume 91, no. 7; July 1998

British Birds
Volume 91, no. 7
July 1998

Handbook of the Birds of the World. Volume 4. Sandgrouse to Cuckoos.
Edited by Josep del Hoyo, Andrew Elliott & Jordi Sargatal.

Lynx Edicions, Barcelona 1997. 679 pages; 70 colour plates; 250 colour photographs; 850 distribution maps. ISBN 84-87334-21-0. £ 110.00.

This series is a reviewer's nightmare. By vol.3, all the superlatives have already been used. It is even appearing quickly, on a tight schedule, and is solidly bound.

First, however, we should consider the good points. The texts describing family characteristics are not only informative and comprehensive, but are also beautifully written, so that they are a pleasure to read. The species texts are succint, but remarkably comprehensive and well referenced, and, although they are in a tiny type, are made readable by good design and use of clear print which could hardly be bettered. The maps are small, but cover an appropriate portion of the Earth's surface in each case, so that they, too, are ideal for reference.

The paintings (by 18 artists in this volume -half of whom are, notably, Bird Illustrators of the Year) are all good as individual portraits, but also provide splendid comparisons between species (e.g. 16 pigeons on a page); many plates could fairly be described as beautiful, and some are exquisite.

The photographs -yes, there are photographs as well! -portray behaviour as well as plumage, are reproduced exceptionally well and many are simply stunning.

Recently, while judging Bird Photograph of the Year, a typical ornithological question came up (as we were looking at Dr Jens Eriksen's photograph of a male Chestnut-bellied Sandgrouse Pterocles exustus rising from a pool): Do female sandgrouse ever carry water on their breast feathers to the nestlings in this way? Turning to the recently received volume, we read:

'How water is brought to the chicks is perhaps the most surprising and most written-about aspect of sandgrouse breeding behaviour. It is curious too that although the truth was discovered at the end of the last century, it was not generally accepted until fairly recently. In 1896, Meade-Waldo published an account in The Zoologist (British Birds' precursor), that was both lively and accurate, of how a male Pin-tailed Sandgrouse (P.alchata) entered a drinking pool, saturated his belly feathers with water and then proceeded to run back to his recently hatched chicks, whereupon they crept beneath him and sucked at his feathers. In several later works, up to 1922, Meade-Waldo continued to insist on the reality of this phenomenon, which had been observed in other species by other bird-fanciers, such as St Quentin who had seen it in the Chestnut-bellied Sandgrouse. However, for some strange reason it was repeatedly asserted that the whole story was pure fantasy and that one could only go as far as saying that sandgrouse might possibly regurgitate like other birds. This state of affairs continued until, in July 1960 near Baghdad, Iraq, S. Marchant happened to observe a male Spotted Sandgrouse (P.senegallus) in the wild giving water to his two chicks. The following year, the same author made a similar observation, but this time of a Pin-tailed Sandgrouse, and then a few years later T. J. Cade and G. L. Maclean published a comprehensive study about the Namaqua Sandgrouse (P. namaqua), which cleared up the matter once and for all.

'Before taking water into their feathers, the males normally rub their bellies on the ground, presumably to get rid of or reduce the oily film on their feathers, then they enter the water and rufle their ventral feathers, at the same time rocking to and fro. Sometimes they drink at the same time, though not always. When they reach the chicks they walk with their legs wide apart, instead of placing one foot in front of the other, as they normally do. They then stand in a strange, erect "Watering Posture", which allows the chicks to strip the feathers of water. While the chicks are thus engaged they look rather like a "litter of suckling pigs", as somebody graphically reported. Once they have finished drinking, the males usually rub their bellies on the ground again, perhaps this time in order to get themselves dry.

'The male's belly feathers are specially adapted for carrying water. They are capable of holding up to 15-20 ml of water per gram dry weight, when the equivalent in a synthetic sponge would be little more than 5 ml. The feathers in the proximal sections have barbules without barbicels and are thus not interwoven; they are coiled several times spirally and instead of being arranged at right angles to the barbs, as is the normal arrangement, they are parallel. However, when the keratin is dampened, these barbules uncoil partially and proceed to lie at right angles to the plane of the feather vane or vexillum, so creating a special layer, a kind of felt, capable of holding water and absorbing it by capillary attraction in which an important part must be played by the hairy filament in which the barbules terminate, some tenths of a millimitre in length. Not all the water manages to reach the chicks, since some of it evaporates during flight, but at least a fair amount does. For the Namaqua Sandgrouse, it has been calculated that males can take in 25-40 ml, and that after a journey lasting 32 km and half an hour they would be able to give their chicks some 10-18 ml. If need be, they make some more trips: Pin-tailed and Black-bellied Sandgrouse (P.orientalis) in Spain at times make as many as three in a day; it is frequent to see males at the water-holes alone and not at the usual times.

'In the female too, specialized feathers appear, but they cover much less surface area, which tallies with the fact that the female is rarely seen to wet these feathers at the watering pools, perhaps only if the male has died, or if, as the chicks grow apace, the male's contributions need to be supplemented. Moreover, these feathers seem to be present in all the species except in the Tibetan Sandgrouse (Syrrhaptes tibetanus), which is also unique amongst sandgrouse in the special nature of its habitat; it does not visit watering pools on a daily basis.'

I have given this gigantic quote to demonstrate, by one example, just how readable the text is in this book, how interesting its content, and how valuable for reference purposes. The whole volume is a delight to the eye, and a pleasure for anyone who just enjoys good books.

Secondly, there must be some bad points. No book of this size can possibly be error-free. But, even if I had found one, I would not mention it here, for no-one should be deterred from looking at (and, preferably, owning) all the volumes in this series.