The Hermit Warbler (Dendroica occidentalis) reaches the northern limit of its breeding range in Washington, where its status has been unclear. The Hermit Warbler frequents treetops where it is difficult to observe, and its song resembles those of the Black-throated Gray Warbler (D. nigrescens) and Townsend’s Warbler (D. townsendi). Other than a few references to a preference for tall conifers (Bowles 1906, Dawson and Bowles 1909, Rathbun 1916), mature coniferous forests (Pough 1957), and moderately dense coniferous forests (Cogswell 1957), little was known of its habitat requirements. The few scattered records of Hermit Warblers in Washington prior to 1970 provided little indication of its status, and most authors classified it as uncommon in coniferous forests of western Washington.
In the 1970s the number of records increased substantially as the number of field observers increased. Consequently, Wahl and Paulson (1977) concluded that the Hermit Warbler’s principal range in Washington was the southern Cascade Range and that it was common in that area. However, its status in other parts of the state and its specific habitat requirements were still uncertain. The purpose of this study was to delineate Hermit Warbler habitat requirements and to synthesize existing information on its distribution and abundance in Washington.