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GAP Analysis Predicted Distribution Map

Hermit Warbler (Dendroica occidentalis)

Species Code: DEOC

Click to enlarge Range map

= Core Habitat
= Marginal Habitat

Breeding Range Map
The green area shows the predicted habitats for breeding only. The habitats were identified using 1991 satellite imagery, Breeding Bird Atlas (BBA), other datasets and experts throughout the state, as part of the Washington Gap Analysis Project. Habitats used during non-breeding months and migratory rest-stops were not mapped.

Metadata (Data about data or how the map was made)

Click to enlarge distribution map

Other maps & Information:
  • Breeding Bird Atlas
  • NatureMapping observations
    during breeding season
  • NatureMapping observations
    throughout the year

This species is locally common in Western Hemlock forests of the eastern and southern Olympic Peninsula, becoming more common and widespread in Western Hemlock and Silver Fir forests of the western Cascades, south of Mount Rainier. It is a rare possible breeder in southwestern Washington in the Willlapa Hills (AR). It can be found locally in stands of Lodgepole Pine and Subalpine Fir on the slopes of Mount Adams.

Most authorities consider the Townsend Warbler to be monotypic, i.e. the sole member of its group, but possibly birds breeding on the Queen Charlotte Islands and Vancouver Island in British Columbia are distinct subspecies. The two forms are separable by wing measurements. Modeled similarly to the Townsend’s Warbler, zones within its range limits and above the (peripheral) Ponderosa Pine zone were core. Mid-to late-seral conifer forests were good, and mixed forests and early-seral conifer forests were included.

Much confusion surrounds the identification and distribution of Hermit Warblers with mixed respect to hybrids and Townsend’s X Hermit ancestry: any yellow on the breast below the black chin, any dark barring on the sides or flanks, olive on the back, and any hint of dark facial markings. Any of those characteristics indicates a hybrid bird, not a pheneticlly "pure" Hermit Warbler. Additionally, the popular practice of separating these two species by vocalization is inherently flawed, as individuals throughout the hybrid zone sing song types from both species. In the Willapa Hills, Hermit Warblers are rare breeders, and are much more common in the southwestern Cascades. In the Olympics, a curious elevational "sandwiching" effect occurs, in which Townsend’s Warblers occur below and above Hermit Warblers. Much suitable habitat is found on the Yakima Indian Reservation near Mount Adams (Yakima County), but access restrictions limit our knowledge of this area.

Translated from the Washington Gap Analysis Bird Volume by Uchenna Bright
Text edited by Gussie Litwer
Webpage designed by Dave Lester