Date: 4/5/17 7:04 pm From: Joel Geier <joel.geier...> Subject: [obol] Re: Nashville Warbler breeding status in Coast Range
Paul & All,
As the observer with the observation responsible for that one "POSSIBLE" hexagon in the Polk County Coast range for the Oregon Breeding Bird Atlas -- this was the 1999 sighting near Laurel Peak that I mentioned -- after 18 years of reflection I'm inclined to view that as a case of post-breeding, upslope dispersal.
But dispersal from where? I suspect that if Nashville Warblers nest anywhere west of the Willamette River and north of the Umpqua, it's mostly likely in the drier Coast Range foothills, in south-aspect, oak/madrone situations.
Checking my notes for the Corvallis area in Benton County, in recent decades there have been a couple more records of birds singing for multiple days in late May or June, from around Bald Hill and Witham Hill on the west side of town. There are some older reports of Nashville Warbler detections in the same general area in the middle of the last century, from an old OSU master's thesis.
There are similar habitats in the Coast Range foothills as far north as Dallas, though mostly on private property that's difficult to access.