IBIS - 149 (3) July 2007

IBIS 149 (3) July 2007

DEL HOYO, J., ELLIOTT, A. & CHRISTIE, D. (eds) Handbook of the Birds of the World. Volume 11. Old World Flycatchers to Old World Warblers.

  • 798 pages, 55 colour plates, 343 colour photographs, 733 distribution maps.
  • Barcelona: Lynx Edicions, 2006. Hardback, £138.00, ISBN 849655306X and 9788496553064.

The 11th volume (out of 16 planned) of this major work covers an impressive 724 species in the following families: Muscicapidae (Old World flycatchers: 116 species), Platysteiridae (batises and wattle-eyes: 30), Rhipiduridae (fantails: 44), Monarchidae (monarch-flycatchers: 97), Regulidae (kinglets and firecrests: 6), Polioptilidae (gnat-catchers: 17), Cisticolidae (cisticolas and allies: 144), and Sylviidae (Old World warblers: 270). For the most part, the Editors of these volumes are, very sensibly, following a fairly conventional order of families. However, the current state of understanding of relationships both within and between families means that one can hardly hope to pro¬duce a definitive list of families and their constituent parts. It is, for example, difficult to know how to handle a situa¬tion where there are two fairly distinct groups except for a few species, which fall intermediate between the two. One option is to keep the two groups as families, knowing full well that some species lie very close to the dividing line. The alternative is to say that it is wiser to encompass the whole lot within a single, large family, such as the Fringillidae (close to 1000 species) created by Sibley and Monroe (1990).

This same problem is immediately apparent in this volume. Sibley and Monroe created two large families: Muscicapidae (449 species) and Sylviidae (552). The Editors of these volumes have - in my view wisely - taken the other route, going for smaller families and discussing the problem species in each case. The Sylviidae, here reduced to 270 species, will almost certainly undergo many transformations before there is a consensus - some of the species may be more closely related to the bulbuls (Pycnonotidae) or the babblers (Timaliidae), themselves fairly ragged families. Indeed, the type genus of the family, Sylvia, seems to be more closely related to the babblers than it is to other warblers. Although the groupings are not likely to be the final ones, Sylviidae as here defined comprises four subfamilies: Megalurinae, Acrocephalinae, Phylloscopinae and Sylviinae. One of the large groups split off is the Cisticolidae, containing the 49 species of Cisticola, but also around a hundred others, including the Madagascan Neomixis, the tailorbirds (Artisornis and Orthotomus], Apalis, Prinia and a number of smaller genera, some of less certain affinities.

There is currently no solution to these complex issues, but the Editors have done a good job in keeping HBW up to date and in making clear the reasons for their decisions. One other problem that arises in these large groups of passerines is that potentially related groups may fall into different volumes, so that it may not be immediately clear to researchers in which volume they will find all the birds for which they are searching. The global index for the series on the HBW website is useful in this regard. A plastic-coated single sheet supplied for the non-passerine volumes, which I use all the time, makes it easy to locate which volume contains which groups of birds, and I hope a second will be produced for the passerines.
All the families covered by this volume are from the Old World with the exception of the exclusively New World gnatcatchers (Polioptilidae: 17 species). This may not be the result of some invasion of the New World from one of the other families covered here as determining the closest relatives of the gnatcatchers is far from resolved. Indeed, one possibility is that they are a sister group of the indisputably New World wrens (Troglodytidae). Nor is it entirely clear that the birds included here in the Polioptilidae are all close relatives; the extraordinarily long-billed Microbates (two species) and Rhamphocaenus (one species) may not be so.

Problematic systematics apart, the book deals with the species covered in its standard and well-tried format. There are detailed introductions to each family, including systematics, morphology, habitat, voice, habits, foods and feeding, and breeding, movements (many are longdistance migrants), relationships with humans (not a lot with the groups in this volume), status and conservation; the whole illustrated with a large array of impressive photographs. The family 'introductions' are impressive texts; for example, that for the Sylviidae exceeds 80 pages. Individual treatment of the species then comprises paintings of the birds, distribution maps and a text. The texts normally run 2-3 to a page (but small print on a large page!), but for species as well studied as the Pied Flycatcher Ficedula hypoleuca, there is a full page.

The topical essay in this volume is entitled 'Ecological significance of bird populations' by Çagan Sekercioglu, a 35-page thought-provoking synthesis of the importance of birds to the world's ecology and the implications of reductions in numbers. The part birds play in the environment is immense, including pollination, seed dispersal, predation (on invertebrates, terrestrial vertebrates and fish); to say nothing of the current problems associated with the spread of diseases such as avian influenza. The implications of the decline or total disappearance of some of these species on the world's environments could be far-reaching.

Finally, a bibliography of close on 7000 references completes a worthy addition to the series.

CM. Perrins