D. P. Wijesinghe - CBCN May 2007 page 83 to 95

When the first modern field guide to tropical Asian birds, A Field Guide to the Birds of South-East Asia by Ben F. King, Edward C. Dickinson and Martin W. Woodcock, appeared in 1975 birdwatchers in the Indian sub­continent and Sri Lanka looked forward eagerly to the publication of a similar guide to the birds of South Asia.

By 1975 Ali and Ripley's monumental 10-volume Handbook of the Birds of India and Pakistan had been completed and the time seemed ripe for a more portable work to meet the requirements of the birding commu­nity. Indeed, Collins, the publisher of the South-East Asian book, was planning to bring out a field guide to the birds of the Indian subcontinent but delays in the descriptive text eventually resulted in the artist pub-lishing the plates with only the briefest annotated text (Ali, Ripley and Dick, 1983).

Today a very different situation exists, with at least three comprehen­sive field-guide format accounts of the birds of this region being avail­able: Grimmett, Inskipp and Inskipp (1999), Kazmierczak and van Perlo (2000), and Rasmussen and Anderton (2005).

Since the publication of Pamela Rasmussen and John Anderton's Birdsof South Asia many reviews of the work have appeared (e.g., Pittie, 2005; Harvey, 2005; Grimmett, 2005; Islam, 2006; Dickinson, 2006; Inskipp, 2006; Rahmani, 2006; de Silva Wijeyeratne, 2006) and the book's author has provided an illuminating account of the actual process of producing it (Rasmussen, 2005a). The following comments refer mainly to Volume 2, which contains the introductory material, detailed species accounts (in­cluding audio spectrograms of vocalisations), appendices, and list of ref­erences.

Notwithstanding the spectacular recent discoveries of distinctive new bird species from Sri Lanka and India (Warakagoda and Rasmussen, 2004; Athreya, 2006), it should be noted that the vast majority of spe­cies and subspecies of South Asian birds (i.e., morphologically distinct taxa) recognised today were known to ornithologists by the early twenti­eth century. One may therefore legitimately ask, in what significant manner has the taxonomy of South Asian birds changed over the last century?

Some taxonomists believe that the adoption of the subspecies cate­gory and trinomial nomenclature in ornithology in the early decades of the twentieth century, with the later application of the so-called biologi­cal species concept, has been detrimental to bird taxonomy. The subpe­cies category provided a loophole for describing many 'new' taxa (races or subspecies) on the most flimsy evidence. More damagingly, these views were used to justify 'lumping' together many previously known morphologically distinct allopatric (geographically non-overlapping) spe-cies as 'subspecies' of widespread 'polytypic' species. If the subspecies category was adopted consistently as the unit of diversity in ornithology little harm would have resulted. Instead, a strange double-standard came to be applied in the study of birds.

Even while admitting that many subspecies were diagnosably distinct forms, ecological and other studies on birds tended to focus on species rather than subspecies, and the literature for bird identification dealt inadequately with the differences between the individual subspecies of polytypic species. Over the years non-taxonomists and birders have come to view subspecies as of significance only to museum-based orni­thologists, minor variations of widespread species that could safely be ignored, overlooking the fact that many so-called 'subspecies' are often distinguishable even in the field and had previously been treated as valid species.

Since discussions of bird diversity also focus on species, rather than subspecies, and the hidden diversity represented by polytypic species is routinely ignored these developments naturally lead to a significant underestimation and misrepresentation of bird diversity globally. 'Lump­ing' together of previously recognised species to form polytypic species was invariably done (mainly in the 1920s to 1950s) in the absence of phylogenetic analysis and as a result most currently recognised polytypic species are merely subjective aggregates of populations which are assumed (but not shown)  to be monophyletic.

Biodiversity conservation relies on precise recognition and documenta­tion of the organismic diversity it seeks to conserve. If, however, differ­ences between taxa are downplayed and morphologically diagnosable species are downgraded to mere 'subspecies' what might the conse­quences be? Given that many of these forms are narrowly endemic and occupy places and habitats threatened with destruction we will very likely lose these unique taxa without even being aware of our loss and before we understand their particular significance in the history of life. (For a recent critique of polytypic species and the biological species con-cept see Zink, 2006.)

I have discussed these issues before (1994, 1998) but feel compelled to repeat them here for one reason: Pamela Rasmussen's Birds of South Asia is a step in the right direction towards rectifying the excesses of the past.

Sidney Dillon Ripley (1913-2001) was very much part of the subspe-cies / polytypic species movement and his Synopsis (1961, revised 1982) and Ali and Ripley's (1968-1974) Handbook are products of this trend in ornithology. Although Birds of South Asia traces its origins to Ripley, it differs substantially from that author's work in its treatment of bird taxa at the species level. Though not critical of the biological species concept, Rasmussen has taken a more evidence-based approach to delimiting spe-cies and, thanks to her painstaking museum-based research and analysis of vocalisations, we have here not only an excellent manual for the identification of South Asian birds but also a valuable reassessment of species-level taxa in the region.

Pamela Rasmussen (who received her Ph.D. from the University of Kansas in 1990 and is currently an assistant curator in mammalogy and ornithology at the Michigan State University Museum) joined Ripley's South Asian field guide project at the Smithsonian Institution as a re-placement for Bruce M. Beehler, Ripley's long-time assistant, with no previous experience of the birds of tropical Asia. To a relative newcomer to South Asian birds faced with the task of producing a field guide to the subregion it might have been appealing to simply accept Ripley's (1982) taxonomy and concentrate on getting all the birds to be included illus­trated in a field guide format, with a brief descriptive text.

Fortunately, Rasmussen is a perfectionist who is apparently not put off by the prospect of hard work. Detecting problems with distribution records and taxonomy and unprepared to accept at face value much of the published information on South Asian birds she has done an enormous amount of work gathering material for this book through original speci­men-based research. She realised early in the project that it would be impossible to undertake a serious study of the South Asian avifauna without reference to the bird collection of The Natural History Museum, formerly British Museum (Natural History), at Tring, in Hertfordshire, UK. Making use of material in that and other institutions with substantial holdings of South Asian bird specimens in Europe, the USA and South Asia (and forming collaborative links with colleagues in South Asia and elsewhere) she has been able to undertake a review of South Asian birds on a scale rarely attempted before.

Following from this work a significant number of morphologically dis­tinct taxa that are treated as subspecies in other publications are restored to their original status as valid species. In most of these cases new evidence from vocalisation has been used to corroborate what had previously been established from morphology and such revisions of status can hardly be considered controversial.

Endemic Sri Lankan species resulting from these revisions are: Pompa­dour (Ceylon) Green Pigeon Treron pompadora, Crimson-backed Wood-pecker Chrysocolaptes stricklandi, Ceylon Swallow Hirundo hyperythra, Ceylon Woodshrike Tephrodornis affinis, Ceylon Scaly Thrush Zoothera imbricata, Ceylon Scimitar Babbler Pomatorhinus melanurus and Ceylon Crested Drongo Dicrurus lophorinus. In addition, the Ceylon Small Barbet Megalaima rubricapillus and the Black-capped Bulbul Pycnonotus melan­icterus are treated as specifically distinct from related mainland forms (as in Wijesinghe, 1994), though somewhat inexplicably the Ceylon Hill Munia Lonchura kelaarti is not considered specifically distinct from L. jerdoni (and vernayi) of south India.

The last seems somewhat reactionary, since there is at least as much morphological difference between Lonchura kelaarti and L. jerdoni (and vernayi) as, for example, between Treron pompadora of Sri Lanka and related mainland populations, or between Columba torringtonii of Sri Lanka and the Indian C. elphinstonii. Problems such as this merely serve to illustrate the subjectivity involved in the treatment of taxa when applying the biological species concept and should be sufficient reason to abandon this concept altogether and adopt diagnosable distinctness of populations as the only criterion for delimiting species.

Other Sri Lankan endemic species agree with previous treatments, and the celebrated Serendib Scops Owl Otus thilohoffmanni, discovered by Deepal Warakagoda in 2001 and described by Warakagoda and Rasmus­sen in 2004, makes its first appearance in a book here.

A significant number of species that occur in South Asia are treated in a much more circumscribed manner than in recent regional (e.g., Inskipp, Lindsey and Duckworth, 1996) or world (e.g. Sibley and Monroe, 1990; Dickinson, 2003) lists. Among the many changes proposed are the sepa­ration of the western and eastern forms of the Cattle Egret, Water Rail and Stone-Curlew, the separation of the Jungle Nightjar of peninsular India and Sri Lanka from the Grey Nightjar, the separation of the Bay Owl of southwest India and Sri Lanka from the form found further east, and the separation of the Blackbird of peninsular India and Sri Lanka from the palearctic species. In some cases taxonomic changes are pro­posed in a tentative manner, perhaps due to insufficient data on all of the relevant forms. Although the taxa thus established have been recog­nised as valid species in the older literature many have not been treated as such in recent publications. Additional justification for some of these changes are provided by the author in other publications (e.g., Rasmus­sen, 2005b). Users of this work will need to pay careful attention to these changes that affect both resident as well as migrant taxa.

In the light of my comments above one could argue that Rasmussen should have gone further, certainly in all cases involving widely sepa­rated populations with discrete morphological differences. Nevertheless, Birds of South Asia marks an important change in direction with regard to species level taxonomy that one hopes will help reverse the wholesale 'lumping' together of distinct allopatric populations that took place in the past.

Problems with the accepted taxonomy are discussed under each spe-cies, at least briefly, even when no changes are made. In a small num-ber of cases (e.g., Corvus macrorhynchos complex) uncertainty regard­ing specific status is expressed by inserting the more inclusive name in square brackets between the generic and specific names, e.g. Corvus [macrorhynchos] levaillantii, Corvus [macrorhynchos] culminatus. This practice is sometimes employed in taxonomy to indicate superspecies groupings but it is unclear if that is intended here. In following this convention for species in the Pomatorhinus horsfieldii - Pomatorhinus schisticeps complex the name schisticeps is used for the more inclusive taxon. However, since Pomatorhinus horsfieldii Sykes, 1832 antedates Pomatorhinus schisticeps Hodgson, 1836, the former specific epithet should be employed to denote the more inclusive taxon. (This error probably comes from the first edition of Ripley's Synopsis and Ali and Ripley's Handbook.)

A curious phrase used by Rasmussen as a qualifier of statements on distribution and endemicity (partially explained in the Glossary) is "taxonomy-dependent." In fact, a statement about the distribution (and endemicity) of any taxon is dependent on its taxonomy. For example, the Chestnut-backed Owlet Glaucidium castanonotum and the Ceylon Hill-Mynah Gracula ptilogenys have been treated in the past by some authors as subspecies of Glaucidium radiatum (or G. cuculoides) and Graculareligiosa, respectively, so their status as Sri Lankan endemics is taxon­omy-dependent. Of course, endemicity statements in Birds of South Asia refer to the entire subregion, rather than particular countries. It would appear that the phrase is used in cases where the species limits adopted in Birds of South Asia differ from those in previous standard publications, thus affecting endemicity or extralimital distribution.

Much has been written on the higher classification of birds since the publication of Sibley and Ahlquist's (1990) classification based on DNA-DNA hybridisation. In recent years many contributions to this subject have been made from both morphological and DNA sequence studies using direct character evidence, rather than measures of overall (phe­netic) similarity. While some of the conclusions of Sibley and Ahlquist have received support from these recent studies other points in their classification have been shown to be unfounded and, as a result, we are still far from a well-supported modern classification of the world's birds. (See Cracraft et al. [2004] and Jønsson and Fjeldså [2006] for refer­ences and synthesis.) Given this state of affairs authors of regional works must decide whether to use an out-dated 'traditional' classification that may be faulty but has the advantage of familiarity, follow the prob­lematic novel Sibley and Ahlquist classification, or adopt more rigorous but still incomplete recent findings.

The classification and systematic sequence in Birds of South Asia is a relatively conservative one derived (according to the introduction) from the scheme in Manakadan and Pittie (2001), which itself is based on Ripley (1982). There are, however, some significant deviations from that work that involve generic limits as well as family composition and sequence where an attempt has been made to incorporate some recent findings. Among these changes, grouping the chats and robins with the Old World flycatchers (as the Muscicapinae) separate from the typical thrushes (Turdinae) appears to be a well supported feature of the Sibley and Ahlquist classification. Significant changes with respect to the generic and familial classification of Old World warblers and babblers are expected in the near future, some of which are anticipated in this book.

The laughing-thrushes usually placed in Garrulax (e.g., Ripley, 1982) have been allocated to several smaller genera in this work based, according to Rasmussen, on Baker (1922) and Alice Cibois's (2003) in­complete molecular studies. Rasmussen states: "The generic groups used here are those of Baker (1922), which are based on defined morpho­logical characters (a few exceptions are noted in individual accounts); this is largely concordant with a recent DNA phylogeny (Cibois 2003)." This statement is a little misleading, as Cibois's study did not include many laughing-thrush taxa covered in Birds of South Asia, and the com­position of Baker's genera is significantly different to the one adopted here. Baker placed the Ashy-headed Laughing-thrush (cinereifrons) in the genus Turdoides, not Garrulax, and placed its close mainland rela­tives the Wynaad Laughing-thrush (delesserti) and Rufous-vented Laugh­ing-thrush (gularis) in Garrulax. The generic allocation of the endemic Ashy-headed Laughing-thrush in Birds of South Asia remains unchanged from Ripley (as Garrulax cinereifrons), yet delesserti of the Western Ghats and several other taxa are placed in Dryonestes. Long ago in his original description of the species Edward Blyth (1852) expressed the view that the Ashy-headed Laughing-thrush of Sri Lanka was closely related to delesserti of southwest India. It remains to be seen whether additional morphological studies and molecular data will add support to this hypothesis.

New studies published since this work went to press affect the classi­fication and nomenclature of South Asian birds. Based on their phylo­genetic analysis of the terns Bridge et al. (2005) placed the Sooty Tern and Bridled Tern in the genus Onychoprion and species of the Little Tern group in the genus Sternula. That the Rufous Woodpecker should be returned to the monotypic genus Micropternus (as done by Rasmussen) and not placed with the Neotropical Celeus woodpeckers has recently been confirmed (Benz et al., 2006). The Grey Tit (Parus cinereus) of tropical Asia must once again be recognised as a species separate from the Great Tit (Parus major), according to Päckert et al. (2005). R. B. Payne is credited with showing that the correct spelling of the specific name of the Green-billed Coucal should be chlororhynchos; in fact, this spelling has been in use in Sri Lanka for many years (see Gehan de Silva Wijeyeratne's notes to Martin Wijesinghe's [1999] account of nesting in this species).

The decision to follow a more traditional classification and sequence of species will please birders who found the Sibley and Monroe (1990) clas­sification and sequence in Grimmett, Inskipp and Inskipp's (1999) other­wise excellent guide an inconvenience.

Common (i.e., English) names in Birds of South Asia are said to follow Mankadan and Pittie (2001) but there are many differences. As in that work, 'Ceylon' instead 'Sri Lanka' appears in the English names of most taxa traditionally so designated, except in the case of the Ceylon Warbler, which is called Sri Lanka Bush-warbler. Readers who require lists of spe­cies endemic to various portions of South Asia according to the taxon­omy followed in Birds of South Asia (e.g., South Asian mainland, Sri Lanka, etc.) should consult the review by de Silva Wijeyeratne (2006) which is available online.

A noteworthy aspect of Birds of South Asia is that it is entirely up-to-date as far as Sri Lanka is concerned with regard to new records of occurrences of rare or vagrant birds, thanks, no doubt, to the contribu­tions of Deepal Warakagoda. These records are mentioned not only in the text but indicated also on the distribution maps. The amount of comprehensive coordinated revision required to maintain consistency throughout the work as it progressed must surely have been very con­siderable.

Recently there has been much excitement among some birdwatchers in Sri Lanka at the prospect of a second species of iora existing in the island. An iora specimen from Nilgala, Bibile (Uva Province, Sri Lanka) in the collection at Tring (registration number BMNH 1948.57.54) has been re-identified as Marshall's Iora Aegithina nigrolutea by Wells et al. (2003). Following the publication of Birds of South Asia, where this record is mentioned, there have been several sightings in Sri Lanka of ioras with nigrolutea-like features. Additional field studies and examina­tion of specimens should clarify the status of this taxon in Sri Lanka.

The introductory material, among other matters, deals with problem­atic records originating from two individuals. The ornithological frauds of Richard Meinertzhagen, which came to light largely in the course of research for this book, have received a good deal of publicity, even out­side ornithology (see the excellent article by John Seabrook in The New Yorker, which includes an interesting account of Pamela Rasmussen her­self). Surprisingly, it seems that many problematic records and question­able observations are attributable to E. C. Stuart Baker, author of the highly influential second edition of the Fauna of British India: Birds. The introduction and one of the appendices contain brief historical accounts of the study of birds in the region. That Salim Ali's many contributions to Indian ornithology receive little recognition in these accounts is puzzling.

Birds of South Asia is the first work on the region to carry an exten­sive series of audio spectrograms of vocalisations. Audio spectrograms (or sonagrams) are graphic depictions of sound that graph the distribu­tion of frequency (vertical axis) with time (horizontal axis), with loud-ness indicated by the intensity of the graph. (A waveform is a simpler visual depiction of sound in which amplitude or loudness is graphed against time.) Spectrograms were first introduced for the purpose of field identification of birds in a North American book (Robbins, Bruun and Zim, 1966), but have appeared rarely in field guides since then. They are indispensable for the analysis and comparison of audio signals and have been used extensively in describing, analysing and comparing the calls and songs of many kinds of animals, especially birds and frogs. Rasmussen has made excellent use of spectrograms in Birds of South Asia for describing the vocalisations of a large number of birds included. As mentioned above, these have also served as evidence for delimiting species in several groups of closely related birds.

In addition to the spectrograms (not available for all species) the vocalisation accounts for individual species include transcriptions taken directly from audio recordings. Readers unfamiliar with spectrograms may initially find these transcriptions easier to compare with verbal descriptions of calls and songs provided by previous authors. Even these transcriptions (which follow a consistent set of conventions) provide far more information than most previous descriptions.

The transcriptions and spectrograms enable comparisons to be made between different species or between different vocalisations of the same species. The spectrograms all follow the same format and scale, with the vertical axis generally showing a frequency range of 0-11 kHz, except for some birds with very low-pitched vocalisations (e.g. some pigeons and owls) for which the range is 0-4 kHz. The time represented by each spectrogram varies from species to species, from 1 second to as much as 8 seconds or more. Many of the spectrograms are composed of multiple segments (divided by vertical lines) and each such segment pertains to a different individual bird or recording, though the time scale somewhat confusingly runs continuously.

Deepal Warakagoda, a major contributor to Volume 2, has provided most of the recordings from Sri Lanka and his extensive knowledge of birds in the field and experience and expertise in recording birds have ensured that species that occur in Sri Lanka are particularly well-covered by the new transcriptions and spectrograms.

The attention given in this work to vocalisation and the audio spectro­grams provided in it make this book one of the most significant contribu­tions to tropical Asian ornithology. One minor complaint: some of the spectrograms appear overly 'cleaned', with fainter but quite distinct harmonics barely visible or missing altogether (e.g., spectrogram for Tephrodornis affinis at the bottom of page 331), perhaps as a result of adjusting too much the contrast feature in the spectrogram-generating sound analysis software.

The species accounts contain meticulous descriptions of plumages (including variation) and details of distribution. The accuracy and preci­sion of these descriptions appear to be of a very high standard. As a result, Birds of South Asia is far more than a conventional identification guide: it is a comprehensive descriptive synopsis of bird diversity in South Asia that supplements and corrects the information in Ali and Ripley's Handbook.

Volume 1, Field Guide, with its 180 plates by John Anderton and eleven other artists is, of course, aesthetically the more pleasing of the two volumes. The illustrations are of a high standard, capturing accu­rately not only form and pattern but also natural posture in life. My only serious criticism is of the illustration of the Common Mynah of Sri Lanka (form melanosturnus, plate 177, figure 6-SL), which is quite misleading, with the extent of the visible facial skin greatly exaggerated.

With the publication of Grimmett, Inskipp and Inskipp (1999), Kaz-mierczak and van Perlo (2000), and Rasmussen and Anderton (2005), and excellent regional works such as Harrison and Worfolk (1999), birders in the Indian subcontinent and Sri Lanka are now enjoying 'an embarrass­ment of riches' in high-quality identification-oriented books. Let us hope that this will result in higher standards of birding and greater accuracy in field identification.

Acknowledgement

I thank Udaya Sirivardana for his many helpful comments on an earlier version of this article.

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