Caprimulgiformes strikes again

The "Handbook of the Birds of the World" is a super-encylopedia spanning 16 volumes, published by Lynx Edicions and BirdLife International. It really does cover all living species of bird known to science. All 9,000 of them! Well, almost all. A supplemental volume with about 60 entirely new species will be published at some point next year.

This is the fifth volume of the HBW. It describes three very different orders: the Owls (Strigiformes), the Nightjars and allies (Caprimulgiformes) and the Swifts, Tree-Swifts and Hummingbirds (Apodiformes). I always find it fascinating that the screeching, fast and even somewhat bizarre swifts outside my window are actually related to hummingbirds! But the most absurd birds in this volume are surely the Caprimulgiformes. It includes the Potoos, which are perfect mimics of tree stumps - a large color photo shows this strange ability (try to spot the bird in it!). Further, there are the strictly nocturnal Oilbirds, which communicate in bat-like manner through eco-location. Apparently, scientists who visit the caves where the Oilbirds live have to wear protective masks - the damp caves are a haven for a fungus that causes the lung disease known as histoplasmosis.

The text in the HBW is rather heavy and takes some time to get used to. These books, after all, are primarily intended for ornithologists (with or without protective gear). However, the large amounts of illustrations and color photos might appeal to a more general audience. Unfortunately, these books are extremely expensive, no doubt precisely because of the color (and colorful) photos.

I tend to give these books five stars hands down, and so is the case with volume 5.

Bizarre birds

The order Caprimulgiformes may be *the* most bizarre group of birds known to science. It includes nocturnal birds making weird noises easily confused with the song of crickets, birds that actually hibernate, other species that mimic tree-branches, and the ultra-bizarre oilbird, which lives in caves, echolocates like a bat and only eats fresh fruit.

"Nightjars and their allies" is a 773-page book, or rather encyclopaedia about the Caprimulgiformes. This "night jar bible" (as the other reviewer called it) is part of a series called "Bird Families of the World", published by Oxford University Press. The volumes published so far only cover a smaller amount of all extant bird families, however. OUP's series is intended to cover essentially the same ground as "Handbook of the Birds of the World" (HBW). If it will succeed is another matter entirely, since the HBW already covers all bird families in 16 volumes and have more photos and colour plates, giving it a very commercial appearance. "Nightjars and their allies" doesn't even come close, and look more like a boring reference work. The editors of the OUP series seem resentful of HBW's success, suggesting that their references really are better! There's nothing wrong with "boring" reference works about nightjars, provided you are an ornithologist with distinctly nocturnal habits, but most libraries would probably prefer the flashier HBW (which covers the Caprimulgiformes in volume five).

That being said, I don't deny that this mastodon book really does cover everything you ever wanted to know about caprimulgiform birds. How about the timing of their radiations in relation to continental drift, clinal patterns of variation in wing-length of Tawny Frogmouths in Australia, the number of beetles consumed by Common Poorwills, or the relation of moult to the annual cycle of nesting and migration in populations of Chuck-Will-Widows nesting at different latitudes (according to Rohwer 1971). And this just in the introductory section!

The species accounts are just as bizarrely detailed as the ones in HBW. I admit I was impressed by the length to which scientists are ready to go in their study of even the most obscure species. Faeces and stomach-content is studied to see what kind of insects the nightjars have devoured, the scientist sometimes subjecting the poor bird to a technique known as "stomach-flushing". Every preserved museum specimen is analyzed to get insights about moulting. Expeditions are launched to the interior of New Guinea to map the exact range of various species. Indiana Jones and the Crocodile Hunter, please sign in to the left! Despite this, some nightjars have managed to escape the attention even of these thorough ornithologists. The elusive New Caledonian Owlet-nightjar is known only from one museum specimen collected in 1880, a confirmed observation in 1998 and...late Quaternary fossils! It's good to know that there are still some mysteries out there (others would include the relationship between consciousness and matter, the existence of God or the election bylaws of the State of New York, but I'm digressing).

In summary, I can only concur with the other reviewer: if you're writing a PhD thesis on oilbirds, frogmouths, potoos, owlet-nightjars or nightjars, this is definitely a must-have. The rest of us are gasping...or busy checking out the photos in HBW, volume 5.