|Owls are easily recognized; most everyone in the world knows about owls. They are considered creatures of mystery or doom or good luck, depending on where you are. They are wonderful birds to discover during the day, like this huge Great Gray Owl (left) in Yosemite Nat'l Park. But they are primarily nocturnal birds, hunting in the dark by using exceptional hearing and eyes that gather light much better than our own. This Buffy Fish-Owl (below right) was hunting over the tennis courts at the Danum research station in lowland Borneo, where I caught it in a flash.|
|Worldwide, a third of world's owl species are of the genus Otus
(scops-owls & screech-owls); there are at least 55 species, ranging
from abundant species to some of the world's rarest (eg, Seychelles Scops-Owl
insularis). These are almost entirely nocturnal birds and day-roosts
are changed from day to day, like the Western Screech-Owl (below
left). In contrast, among the most diurnal of the owls is the Northern
Hawk-Owl (below center) found in boreal forests, often hunting from
the top of a tree during the long days of the northern arctic summer. Owls
of the genus Glaucidium (pygmy-owls & owlets) are primarily
crepuscular but can occasional appear in broad daylight to the surprise
of all, as did this Northern Pygmy-Owl (below right) that I found
sitting on top a telephone pole at mid-morning.
|Photos: The Great Gray Owl Strix nebulosa was photographed near Crane Flat, Yosemite Nat'l Park, California, on 22 May 1987. The Buffy Fish-Owl Ketupa ketupu was in Danum Valley Reserve, Sabah, Malaysian Borneo, on 8 Aug 1988. The day-roosting Long-eared Owl was in Vineyard Canyon, Monterey Co., California, on 20 Feb 1995. The Western Screech-Owl Otus kennicottii was in Sacramento, California, in Apr 1980. The Northern Hawk-Owl Surnia ulula was along the McKinley Highway, Alaska, on 9 June 1980. The Northern Pygmy-Owl Glaucidium californicum was in the Warner Mts., Modoc Co., California, in Feb 1981. The pair of Burrowing Owls Speotyto cunicularia were in eastern Contra Costa Co., California, 11 Apr 1998. The Great Horned OwlBubo virginianus was nesting in Wildhorse Canyon, Monterey Co., California, on 5 Apr 1996. The pair of Crested OwlsLophostrix cristata was at La Selva, Ecuador, on 27 July 1990 (photo by Ed Harper). The Fraser's Eagle-Owl Bubo poensis was at Makoukou, eastern Gabon, 15 July 1996. All photos © D. Roberson, except Crested Owls © W. Edward Harper.|
Family Book: I rating (out
of 5 possible)
This is not a successful book for those interested in owl identification, taxonomy, distribution, or vocalizations (ie, birders). But it doesn't really aim at that audience -- as one can tell from its title -- and its text may fulfill that goal for a general audience. It just happens that the book attempts to have illustrations of all the world's owls -- some nice photos intermixed with some marginal art and some zoo shots -- and range maps. There apparently is a new edition that I've not seen.Because there was no overshadowing world book, there are many books that cover bits of the world. Some examples are Voous' (1989) Owls of the Northern Hemisphere -- which does have some very fine artwork, including field sketches, by Ad Cameron, and a good solid text on biology -- and Karalus & Eckert's (1974) The Owls of North America -- which is similar is style but has a sparser text and tries (not always successfully) to illustrate by paintings all the races of North American owls. I am aware of similar books on South Africa, or Australia, etc. All these are "coffee-table" books, but many other types of book exist. The literature on owls is extensive.
There is a new book by Koenig, Weick & Becking (advertised as due out Dec. 1998) entitled Owls: A Guide to the Owls of the World, which looks in advertising to be in the same genre as the Pica Press books. I have not seen this book, but I note the advertising claim that it covers "all 206 world species." This suggests to me that the authors (who appear to be European) have adopted some variation of the phylogenetic species concept and essentially split all island forms out as separate "species." This could be a disaster; a fairly recent survey of the owls by Amadon & Bull (1988) which included a reassessment of the genus Otus by Joe Marshall & Ben King (splitters both who emphasize vocalizations) detailed only 162 species (a few more have been discovered since then). As I say, I've not seen the new Owls book, but treat it with caution. It apparently comes with a double CD with voices of many species.
Vocalizations of owls are important. A useful cassette accompanied Marshall's (1978) work on Asian owls. For the New World, the tape by Hardy et al. (1990) is outstanding.
Other literature cited:
Amadon, D., and J. Bull. 1988. Hawks and owls of the world: a distributional and taxonomic list. Proc. West. Found. Vert. Zool. Vol. 3, No. 4: 295-357.
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