Monday, October 26, 2020

Special book review: Ageing and Sexing of Migratory East Asian Passerines

 A few days ago I received this wonderful new book, sent to me by Avium Förlaga Swedish publisher: Ageing and Sexing of Migratory East Asian Passerines.

Authors: Gabriel Norevik, Magnus Hellström, Dongping Liu and Bo Petterson.

423 pp, 1420 colour photographs, text in English and Chinese.

The book arrived in a huge box, amply coated and protected. It is a large book, handbook-sized; at 31*24.5 cm, weighing 2.4 kg, it does not fit in a ringer's box, nor into a backpack. Its price tag of £94.99 on NHBS, and SEK899 on Natur Bokhandeln make it rather heavy for the individual ringer and birder. The book is aimed towards use at ringing stations and bird observatories with generous shelf space and a book budget, or as a reference for 'well-established' field ornithologists, ringers and birders, returning home or to the office from the field. The book covers (only) 62 species, those most prominent at East Asian migration hotspots like Beidahe, where research for this book took place. The other side of the detail versus size trade-off is a huge selection of superb, neat, full-size, hi-res images, covering different ages and sexes. Species accounts typically include 20-30 images per species! The different sections for specific identification, moult, ageing and sexing in autumn and spring, organised in a standard structure, make the information accessible and easy to find. Check this splendid account of an elegant bunting (p.361):

This book was produced through a collaboration between Swedish and Chinese ringers. The text is bilingual, with all text appearing side-by-side, English in left column, Chinese in right. I have no problem with that at all, understanding that the book is there for Chinese and Chinese-reading ringers to use. The introduction contains important information about the basics of bird ringing, including bird topography and terminology in moult. This is crucial, because advanced ringing literature readily available to European ringers for decades, such as Svensson's Identification Guide to European Passerines, first published in 1970 and updated since (maybe even a 5th edition one day?), are unavailable to Chinese ringers, especially if they can't read English. Hopefully, this publication will aid Chinese ringers to catch up in detail and professionalism with their Swedish partners.

It becomes clear when reading the text, concise and coherent, and viewing the photos, sharp, illustrative and instructive, that this book is of the highest professional standards. It includes some pieces of information that may seem trivial to advanced ringers. For example, the sections on feather positions and wing length (p. 23) are there for ringers during their training process:

However, the book mainly contains top-quality data and information about moult, identification and ageing that will increase its appeal to the most serious ringers and birders. This book is based upon years of research, collecting data from thousands of birds, photographing and documenting, mainly at the world-famous migration hub of Beidahe in eastern China. It is evident that the expertise developed by generations of top-class Swedish ringers was transferred to the rich avifaunal region of the Orient. I have not had the chance to read each and every word in the entire text. However, I read very carefully accounts of species I am well familiar with, and found the text to be very accurate, detailed and coherent. I assume this level is maintained throughout the book. I did not spot any errors, though I am sure there are few, as in any detail-packed book.

I wrote above 'only 62 species', because this is another aspect of the trade-off between detail and size. The book focuses only on a small subset of species, and does not include information on many other species of migratory East Asian passerines that were left out. I understand this decision, but acknowledge that this is not a full reference book for the region, unlike those available for European ringers, such as Demongin's 2016 Identification Guide to Birds in the Hand (see my review in Dutch Birding). There's still a need for a full reference for in-hand identification, ageing and sexing of East Asian passerines, migratory and non-migratory, which hopefully will get published in the not-so-distant future.

In my opinion the essence of the book is in the photos, and this is its main advantage. As mentioned above, the book contains many photographs, and they are spectacular. From personal experience, I can testify that producing such high-quality photographs of birds in the hand, standardised in colour balance and position, neat and tidy, is a huge and extremely challenging task. Almost without exception, I think the authors succeeded in this task. I am especially impressed by the photos demonstrating moult limits, that are often extremely slight and difficult to illustrate in photos. A good example for clear display of tricky-to-spot moult limit is Brambling (p. 293):

Another good example for display of moult limit is in Grey-backed Thrush (p. 361):

In photographic guides, accurate colour balance is important too, for example when comparing feathers of young birds versus adults. I found colour separation very good, well-printed, and accurate, for example the difference in base colour of Siberian Accentor coverts of different generations (p. 256):

There are very few exceptions to this, where colour balance is not optimal, for example photos of Eastern Crowned Warbler (p. 81) that are too bright yellow-green:

The ability to display feather wear in photographs is not a trivial task either. In this book, variation in wear is well-displayed, for example in Black-faced Bunting wing photos (p. 384):

While this is mainly a book for ringers, aiding identification, sexing and ageing in the hand, it will surely become popular among avid birders in Europe and North America, keen on finding/identifying/twitching East Asian vagrants on e.g. islands such as Shetland, Scilly, Helgoland, Ouessant, Utsira, Attu and Farralon. The specific identification text and photo section is useful for this. I also found the comparative plates of species-groups very illustrative and helpful, for example grey flycatchers (p. 410-411):

I hope that American birders will cope well with ringing autumn moult grey colours, and use of calendar-years and European moult terminology.

To conclude, I find this book an important reference for ringers, essential for East Asian ringers, but also for European and North American ringers and birders. It is instructive, of high-quality, attractive and accurate. It is indeed big, heavy and expensive; yet, even in our changing world of online publications, I find this book an important addition on any keen book shelf.

Thanks to Avium Förlag for generously providing me with this opportunity to review the book.