Hermit warbler

The hermit warbler (Setophaga occidentalis) is a small perching bird. It is a species of New World warbler or wood-warbler. They are a migratory bird, the breeding range spanning the majority of the west coast of the United States. Their winter range includes parts of Mexico and Central America as well as parts of the southern California coast.

Description
Hermit warblers are dark gray in coloration on top, and white below, and their flanks are streaked with black. The wings have two diagonal white wing bars. The majority of the hermit warbler's head is yellow, and males have a dark black throat, while females have much less black on their throat bib and immature birds have no black throat. Both males and females measure 5.5 in in length, 0.3 to 0.5 oz in weight, and 7.9 in in wingspan.

Diet
Like most warblers the hermit warbler eats a strict diet of insects and spiders, and can often be found hanging upside-down from the ends of conifer branches, like a chickadee, probing for food.

Reproduction
Nests are neat and cup-shaped, constructed from stems, grass, twigs, and pine needles positioned near the tip of a branch high in a conifer tree. The female will lay between three and five eggs, which are white in color and heavily spotted with brown and lilac speckles. Other incubation habits are mostly unknown.

Habitat
Hermit warblers are common, but incredibly shy, birds that dwell in open coniferous forests. They are also found in wetter habitats for nesting, and in various mountain habitats. Their summer breeding range is the majority of the west coast of the United States up to Washington. They will sometimes winter in south-west California, but they are migratory and will winter in Central America as far south as Panama. Other nesting habits are mostly unknown. During migration they can be found in both coniferous and deciduous habitats as well as water lined wooded areas, desert oases, and in suburban areas. You can usually find these birds in Tall Coniferous forest, Douglas fir, Pine, Redwood, and in the mountain like areas.

Effects of climate change
The range of the hermit warbler is expected to change as the climate warms, the breeding range expected to expand north and east but lose much of the current range in Northern California as well as some range in parts of Oregon, Washington, and Canada. Extreme warming will put them at risk of heat waves as well as flooding during the nesting season.

Books

 * Pearson, S. F. 1997. Hermit Warbler (Dendroica occidentalis). In The Birds of North America, No. 303 (A. Poole and F. Gill, eds.). The Academy of Natural Sciences, Philadelphia, PA, and The American Ornithologists’ Union, Washington, D.C.

Thesis

 * Marcot BG. Ph.D. (1985). HABITAT RELATIONSHIPS OF BIRDS AND YOUNG-GROWTH DOUGLAS-FIR IN NORTHWESTERN CALIFORNIA (SILVICULTURE, DIVERSITY, COMMUNITY, CLEARCUTTING, AVIAN). Oregon State University, United States, Oregon.
 * Pearson SF. Ph.D. (1997). Behavioral and ecological tests of four models explaining narrow hybrid zones between hermit and Townsend's warblers. University of Washington, United States, Washington.

Articles

 * Airola DA & Barrett RH. (1985). Foraging and Habitat Relationships of Insect-Gleaning Birds in a Sierra-Nevada USA Mixed-Conifer Forest. Condor. vol 87, no 2. pp. 205–216.
 * Anthony RG, Green GA, Forsman ED & Nelson SK. (1996). Avian abundance in riparian zones of three forest types in the Cascade Mountains, Oregon. Wilson Bulletin. vol 108, no 2. pp. 280–291.
 * Buskirk WH. (1973). 4 New Migrants for Costa-Rica. Condor. vol 75, no 3. pp. 363–364.
 * Easterla DA. (1970). Hermit Warbler in Missouri. Wilson Bulletin. vol 82, no 4.
 * Eckert KR. (1982). The Spring Migration March 1-May 31 1982 Western Great Lakes Region USA. American Birds. vol 36, no 5. pp. 854–857.
 * Erickson RA & Wurster TE. (1998). Confirmation of nesting in Mexico for four bird species from the Sierra San Pedro Martir, Baja California. Wilson Bulletin. vol 110, no 1. pp. 118–120.
 * Gilbert FF & Allwine R. (1991). Spring Bird Communities in the Oregon Cascade Range USA. U S Forest Service General Technical Report PNW. vol 285, pp. 145–159.
 * Granlund J. (1994). Winter Season: Western Great Lakes Region. National Audubon Society Field Notes. vol 48, no 3. pp. 299–302.
 * Greenberg R, Gonzales CE, Bichier P & Reitsma R. (2001). Nonbreeding habitat selection and foraging behavior of the Black-throated Green Warbler complex in Southeastern Mexico. Condor. vol 103, no 1. pp. 31–37.
 * Greenberg R, Keeler-Wolf T & Keeler-Wolf V. (1974). Wood Warbler Populations in the Yolla-Bolly Mountains of California. Western Birds. vol 5, no 3. pp. 81–90.
 * Hagar JC. (1999). Influence of riparian buffer width on bird assemblages in western Oregon. Journal of Wildlife Management. vol 63, no 2. pp. 484–496.
 * Huff MH & Raley CM. (1990). Classification of Breeding Bird Communities in Young Mature and Old-Growth Douglas-Fir Forests of Washington and Oregon USA. Bulletin of the Ecological Society of America. vol 71, no 2 SUPPL.
 * Jackson WM, Wood CS & Rohwer S. (1992). Age-Specific Plumage Characters and Annual Molt Schedules of Hermit Warblers and Townsend's Warblers. Condor. vol 94, no 2. pp. 490–501.
 * Janes SW & Ryker L. (2006). Singing of Hermit Warblers: Dialects of type I songs. Condor. vol 108, no 2. pp. 336–347.
 * Lovette IJ, Bermingham E, Rohwer S & Wood C. (1999). Mitochondrial restriction fragment length polymorphism (RFLP) and sequence variation among closely related avian species and the genetic characterization of hybrid Dendroica warblers. Molecular Ecology. vol 8, no 9. pp. 1431–1441.
 * Manuwal DA & Huff MH. (1987). Spring and Winter Bird Populations in a Douglas-Fir Forest Sere. Journal of Wildlife Management. vol 51, no 3. pp. 586–595.
 * Morrison ML. (1982). The Structure of Western Warbler Assemblages Eco Morphological Analysis of the Black-Throated Gray Warblers Dendroica-Nigrescens and Hermit Warblers Dendroica-Occidentalis. Auk. vol 99, no 3. pp. 503–513.
 * Morrison ML. (1984). Influence of Sample Size and Sampling Design on Analysis of Avian Foraging Behavior. Condor. vol 86, no 2. pp. 146–150.
 * Munson CR & Adams LW. (1984). A Record of Ground Nesting by the Hermit Warbler Dendroica-Occidentalis. Wilson Bulletin. vol 96, no 2.
 * Owen-Ashley NT & Butler LK. (2004). Androgens, interspecific competition and species replacement in hybridizing warblers. Proceedings of the Royal Society Biological Sciences Series B. p. 6) S498-S500, December 497, 2004.
 * Owen-Ashley NT, Butler LK, Rohwer S & Wingfield JC. (2001). The role of testosterone in a moving avian hybrid zone. American Zoologist. vol 41, no 6.
 * Pearson SF. (1997). Competition and reproductive success in a narrow, moving hybrid zone. Bulletin of the Ecological Society of America. vol 78, no 4 SUPPL.
 * Pearson SF. (2000). Behavioral asymmetries in a moving hybrid zone. Behavioral Ecology. vol 11, no 1. pp. 84–92.
 * Pearson SF & Manuwal DA. (2000). Influence of niche overlap and territoriality on hybridization between Hermit Warblers and Townsend's Warblers. Auk. vol 117, no 1. pp. 175–183.
 * Pearson SF & Rohwer S. (1998). Determining clutch size and laying dates using ovarian follicles. Journal of Field Ornithology. vol 69, no 4. pp. 587–594.
 * Pearson SF & Rohwer S. (1998). Influence of breeding phenology and clutch size on hybridization between hermit and Townsend's warblers. Auk. vol 115, no 3. pp. 739–745.
 * Pearson SF & Rohwer S. (2000). Asymmetries in male aggression across an avian hybrid zone. Behavioral Ecology. vol 11, no 1. pp. 93–101.
 * Ralph CJ, Paton PWC & Taylor CA. (1991). Habitat Association Patterns of Breeding Birds and Small Mammals in Douglas-Fir-Hardwood Stands in Northwestern California and Southwestern Oregon. U S Forest Service General Technical Report PNW. vol 285, pp. 379–393.
 * Rappole JH, King DI & Barrow WC Jr. (1999). Winter ecology of the endangered Golden-cheeked Warbler. Condor. vol 101, no 4. pp. 762–770.
 * Ratti JT. (1984). Selected Avian Systematic Problems in the Northwest the 1983 American Ornithologists Union Checklist. Northwest Science. vol 58, no 3. pp. 237–242.
 * Rising JD. (1988). Phenetic Relationships among the Warblers in the Dendroica-Virens Complex and a Record of Dendroica-Virens from Sonora Mexico. Wilson Bulletin. vol 100, no 2. pp. 312–316.
 * Rohwer S. (2004). Using age ratios to infer survival and despotic breeding dispersal in hybridizing warblers. Ecology. vol 85, no 2. pp. 423–431.
 * Rohwer S, Bermingham E & Wood C. (2001). Plumage and mitochondrial DNA haplotype variation across a moving hybrid zone. Evolution. vol 55, no 2. pp. 405–422.
 * Rohwer S & Wood C. (1998). Three hybrid zones between Hermit and Townsend's Warblers in Washington and Oregon. Auk. vol 115, no 2. pp. 284–310.
 * Rohwer S, Wood C & Bermingham E. (2000). A new hybrid warbler (Dendroica nigrescens x D-occidentalis) and diagnosis of similar D-townsendi x D-occidentalis recombinants. Condor. vol 102, no 3. pp. 713–718.
 * Smith CE & Rohwer S. (2000). A phenotypic test of Haldane's rule in an avian hybrid zone. Auk. vol 117, no 3. pp. 578–585.
 * Yocom CF. (1968). Status of the Hermit Warbler in North Western California USA. Murrelet. vol 49, no 2. pp. 27–28.

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