Years ago I found an Audubon's Warbler nest with eggs in the lower branches of a Douglas fir here on the farm at Thornton Creek, Lincoln, but it is the only breeding record I have had at this location.
Oh- as far as I can tell they are not breeding in the Doug-fir/ hemlock forest that make up much of the Coos Coast Range but do breed in the Siskiyous where the forest are more open and there are one or more pine species present.
Audubon’s Warblers are regular breeders in Coos County in areas with shorepine along the coast- but much less common than Orange-crowns though. They’re also regular breeders in areas with lodgepole in the Cascades. These two trees species are varieties of Pinus contorta of course. Interesting!