>Most unusual were Nashville Warblers widespread in conifers, especially in
>regenerating lodgepole pine, but also grand fir, as well as the expected
>willow, aspen and deerbrush thickets.
(snip)
I wonder if an insect outbreak might cause this
>species to temporarily colonize different habitats? Curson et al. in *Warblers
>of the Americas* state: "breeds in sparse, young deciduous and mixed woods,
>especially in areas of aspen and birch; also second-growth clearings and
>spruce
>bogs."
(snip)
The density of Nashville Warblers in
>this habitat was exceptional - I could always hear 5-7 at any one point.
(snip)
Perhaps...coincidentally, Evening Grosbeaks were as numerous
>or more so than Nashville Warblers in these areas - as well as everywhere else
>where I birded.
(snip)>
>I'd be very interested if anyone out there can explain what seemed to me to be
>extraordinary with these Nashville's!
>
>Andy Stepniewski
>Wapato, WA

Several kinds of warblers (Cape May, Bay-breasted that I recall) are known
to home in on outbreaks of insects in conifers, especially spruce budworms
but also others. Evening Grosbeaks are well known to do this, and I have
seen Western Tanagers in great abundance under such a circumstance; I
haven't observed any warblers doing this in WA, but why not? Perhaps the
grosbeaks point toward an insect outbreak. Did you look for insects in the
lodgepoles? Lodgepole loopers (there should be such a bug, if there
isn't)?

Dennis Paulson, Director phone: (206) 756-3798
Slater Museum of Natural History fax: (206) 756-3352
University of Puget Sound e-mail: dpaulson at ups.edu
Tacoma, WA 98416