Subject: another Sibley comment
Date: May 19 16:41:49 2001
From: Netta Smith - nettasmith at home.com


Every time I look closely at range maps in field guides, I find errors. For
example, I just realized the map of the distribution of the Ruddy Duck in
Sibley's field guide makes it look as if it's resident in the Rockies of
southern Canada and northern Idaho. Not only is it not *resident* there
(all water bodies probably freeze in winter), but I doubt if it even breeds
in much of that area. It's definitely not a mountain duck (to me, it's
always been more of a bathtub duckie). Birds of Canada shows it as absent
from the Canadian Rockies, Peterson shows it absent from both Canadian and
Idaho Rockies, and Kaufman and NGS show it breeding throughout the mountains
(their maps are too small to show such gaps) but not wintering there. This
is probably a slip of the paintbrush by Sibley. I think the best published
range maps are still those of Peterson, which are just large enough to be
able to show such details well.

David Sibley has said he is working on revising his range maps. It would be
a great exercise if every day someone sent in a range-map correction for a
much-used field guide!

Dennis Paulson
--
Netta Smith and Dennis Paulson
1724 NE 98 St.
Seattle, WA 98115