rising@utzoo.uucp (Jim Rising) (11/30/88)
It's a big order to list field guides for everywhere, but there are
guides for most places. Any region that you're particularly
interested in?
Concerning the Tundra Swan, look at the picture of the Whistling Swan
in your North American field guide. The "Whistling" swan of the
New World and "Bewick's" swan of Eurasia are tundra-breeding
geographical representatives (generally considered subspecies)
of the same species or superspecies. The A.O.U. at present considers
them to be conspecific, and uses the name Tundra Swan for the two
combined. In the field you might be able to tell Bewick's Swan from
Whistling. Adult Whistling Swans usually have a yellow area confined
to the lores whereas in Bewick's the lores and basal half of the
upper mandible are usually yellow (this generally terminates at about
the nostril). Bewick's Swan is illustrated in any of the guides to
birds of Britain and Europe, such as:
Bruun, B. 1970. The Hamlyn Guide to Birds of Britain and Europe.
Hamlyn Publ. Group, London.
British birders have told me that they like the Collins guide best,
but I don't have one at hand to give reference.
The A.O.U. Check-list lists Bewick's Swan as "casual or accidental"
in the Aleutians, Oregon, California, Saskatchewan, Maryland.
Whistling Swans should winter regularly in central California--so
your Tundra Swan is probably a "Whistling Swan." Look for the yellow
on the bill.
--Jim Rising
--
Name: Jim Rising
Mail: Dept. Zoology, Univ. Toronto, Toronto, Ontario, Canada M5S 1A1
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