The Enigma of the Owl: An Illustrated Natural History by Mike Unwin and David Tipling, with a foreword by Tony Angell Yale University Press, 288 pp., $40.00 Owls: A Guide to Every Species in the World by Marianne Taylor Harper Design, 256 pp., $50.00

Humans have always noticed owls. One of the earliest examples of Paleolithic art is an owl engraved on the wall of the Chauvet cave in France.1 Among the peculiarities of owl physiognomy is that owls have both eyes facing forward, unlike most birds. They can also turn their heads 270 degrees (making up for their inability to move their eyes). It has been easy to imagine that these creatures of darkness, mostly experienced as an ominous cry in the night or a disconcerting stare during the day, have personalities, and malign ones at that. Even today, the two books under review tell us, in many parts of the world owls are killed whenever they are encountered, for fear of their evil influence.

The Greeks perceived owls more positively, as embodiments of wisdom. The “owl of Athena” portrayed on Athenian coinage represents a real species, the little owl (Athene noctua), which can still be seen among Mediterranean ruins. Nowadays Europeans and Americans generally regard owls as benign but sometimes as pretentious, as in The Stuffed Owl: An Anthology of Bad Verse, which famously mocks poetry of “sentimentality” and “banality,”2 or the pompous know-it-all in A.A. Milne’s Winnie-the-Pooh who misspells his own name “Wol.”

The truth about owls is less fantastical but no less interesting than what humans project onto them. Owls’ remarkable physical attributes were shaped by the imperatives of the hunt. They are impressive killing machines, capable of dispatching other birds or animals larger than themselves. Central to this are big legs and claws, wing feathers designed for silent flight, and highly sensitive eyes and ears. Owls have acute binocular vision and, contrary to legend, can see in daylight.

Hearing is even more important to owls than seeing. Their ears make it possible for them to locate prey in total darkness. In some owls, one ear is larger than the other and located higher on the head, so they can locate rustling mice by aural triangulation. Some of the photographs in The Enigma of the Owl by Mike Unwin and David Tipling show arctic species, such as the great grey owl, diving deep into snow to capture rodents that they have located entirely by sound. The ear-like tufts on some owls’ heads have nothing to do with this superb hearing system, which is covered by feathers. The tufts probably evolved as a device for camouflage in daylight.

There are over two hundred species of owls, but the exact number keeps changing. Therefore Marianne Taylor’s rash promise to portray “every species in the world” is impossible to keep. On the one hand, vulnerable species are going extinct. The laughing owl of New Zealand…