Tweeters,

The winter abundance of Townsend's and Yellow-rumped Warblers is
intriguing, because it varies in different parts of western Washington
and southwestern B.C. As Eric Kraig notes, Yellow-rumped Warblers
winter in large numbers around Ocean Shores and elsewhere along the
southwest Washington coast, where their main food is probably the
fruit of the wax-myrtle or California bayberry-- in the same way that
a related species is the main winter food of the "Myrtle" warbler on
the Atlantic and Gulf coasts. Away from the immediate coast,
Yellow-rumps are generally uncommon to rare in winter, but I would
have said they were more frequent than Townsend's in most areas.

I had a look at the Olympia CBC results from 1990 through 1999,
and contrary to Eric's impression, they suggest that Yellow-rumped is
a bit more numerous than Townsend's. The totals for the 10-year period
were 138 Yellow-rumps (including both "Audubon's" and "Myrtle" forms)
and 116 Townsend's. I'm not sure if this is typical for the Puget
Sound area. Comments, anyone?

In the Vancouver, B.C. area, by contrast, Townsend's is very rare
in winter-- despite temperatures which are very close to those in
Seattle or Olympia. The Ladner CBC (which includes Point Roberts)
recorded its first Townsend's in its 40-year history this winter, and
the Vancouver CBC has logged Townsend's only 3 times in the last 31
years. On the other hand, the Ladner CBC has recorded Yellow-rumps 21
of the last 38 years, and the Vancouver CBC, 18 of 31 years.
Yellow-rump totals average fewer than 10 birds on both CBCs, but have
been as high as 87 for Vancouver and 39 for Ladner.

The second most frequent wintering warbler at Vancouver is easily
the Orange-crowned (seen 11 out of 31 years at Vancouver, and 11 out
of 38 at Ladner.)

Townsend's Warblers are seen much more often in winter even at
Bellingham than at Vancouver, and are also much more frequent in the
Gulf Islands and around Victoria (which are a couple of degrees warmer
in winter.) The rarity of Townsend's in winter around Vancouver is
anomalous, but it seems to be real.

Aren't Christmas Bird Counts wonderful? It is easy to speculate
about the status of certain species based on one's own experience, but
you can make much more definitive statements by reviewing Christmas
Bird Count data, which summarize the experience of hundreds of
observers over a period of decades. Thank goodness we have this
wonderful data source. The efforts of the thousands of birders who
slog it out through the woods and fields every winter really are
worthwhile!

Wayne C. Weber
Kamloops and Delta, B.C.
Phone: (250) 377-8865
wayne_weber at bc.sympatico.ca
(Former CBC compiler for Vancouver, 1973-1994, and CBC editor for
Western Canada, 1980-1984)