Hi Tweeters

Way back on July 03, Gene Hunn said:

(snip)
>I also noticed that above 5000 feet on the crest nothing but Yellow-rumped
>Warblers, while down at 4500 and below Townsend's Warblers were abundant
>and Yellow-rumpeds scarce. Might Yellow-rumped largely replace
>Townsend's in coniferous forests above 5000 feet?

Hmmm. Something odd here. In Vancouver BC, the highest mountains around the
city are the North Shore mountains, Mts. Seymour, Grouse, Hollyburn, and
Black, all over 4000' but less than 5000' (I'm tired of converting to metric
today), most covered in coastal doug fir, cedars, hemlocks, etc. If we have
breeding Townsend's Warblers (TOWA), they're from mid-mountain and on up;
the breeding Yellow-rumped Warblers (YRWA) nest in mature doug fir and red
cedar no closer to the coast than about 3 miles, but down near sea level. Go
figure.

Speaking of TOWA, I have a query I've already put to Jack Bowling. I was in
the forests (Engelmann spruce, subalpine fir, lodgepole pine old-growth--a
big tree there would be about 100'--150') in the NE part of BC about a
hundred miles NE of Fort St. John from early to mid-May this year in the
eastern foothills to the Rockies (going for the Guinness Record for the most
consecutive prepositional phrases). A couple of years earlier, I worked in
the forests about 90 miles to the W. In between, there's about 40-50 miles
of fairly low (5-7 thousand feet) glacially beaten-up mountains, and pretty
continuous habitat in between the two work sites. In the western site, Donna
Creek, breeding TOWA were the commonest forest warbler with *no*
Black-throated Green (incidentally, breeding YRWA were about 1/2 as common
in the same forest); at the eastern site, the opposite (with YRWA still
quite common). They seem to arrive roughly about the same time. Apparently,
there's little, if any, hybridisation. What keeps them apart?

Michael Price
Vancouver BC Canada
michael_price at mindlink.bc.ca