Ash-throated Flycatcher Myiarchus cinerascens Scientific name definitions

The Ash-throated Flycatcher is a familiar sight and sound during spring and summer across much of western North America as far north as central Washington, Idaho, Wyoming, and western Colorado and south to central Mexico, occurring in a variety of lowland to mid-elevation habitats, including desert scrub; open deciduous, coniferous, and mixed woodlands; and riparian forest. Except for year-round presence in parts of extreme southeastern California and southern Arizona, Baja California, and Sonora, the species is completely migratory. Ash-throateds move south during late summer and early fall, generally departing the United States by mid-September. Most winter on the Pacific slope from Mexico to Honduras, with some found regularly on the northeastern coastal slope of Mexico and irregularly in the desert lowlands of the extreme southwestern United States. Throughout most of the breeding range, especially at high elevations and at more northerly latitudes, where breeders arrive relatively late in the spring (mid-April to May), only a single brood is raised. In more southerly low-elevation desert areas, breeders arrive much earlier (March to mid-April) and, at least locally, are able to raise 2 broods.

Because Ash-throated Flycatchers are tolerant of high temperatures, do not need to drink water, and can nest in relatively small cavities, they can breed even in sparse desert scrub as long as adequate food resources and nest sites are available. Territory size varies substantially depending on habitat structure and quality and nest-cavity availability. Highest densities and smallest territories tend to be associated with riparian corridors. A secondary cavity nester, this species will readily use human-made cavities such as nest boxes and hollow metal fence poles; this adaptability has probably resulted in population increases (or at least helps offset loss of natural habitat), and has allowed some local expansion into previously unoccupied areas.

The slightly shorter-winged, longer-billed, non-migratory population of central and southern Baja California is considered a separate subspecies. Otherwise, there is only minor geographic variation in size and practically no detectable variation in plumage coloration within the species. Over much of its breeding distribution in the western United States, this flycatcher is the only regularly occurring member of the difficult-to-identify genus Myiarchus . Identification can be more challenging, however, in more southerly and southeasterly breeding areas and in winter, where extensive distributional and habitat overlap can occur with other superficially similar species: Brown-crested (M. tyrannulus), Great Crested (M. crinitus), Dusky-capped (M. tuberculifer), and Nutting's (M. nuttingi) flycatchers.

As with many other common North American species, the Ash-throated Flycatcher is surprisingly understudied, despite being widespread in the American West and a somewhat more accessible subject than its more canopy-dwelling relatives, the Brown-crested and Great Crested flycatchers. Our knowledge of the species is generally anecdotal in nature, with the exception of thorough analyses of morphological and vocal systematics by Lanyon (Lanyon 1961 Lanyon, W. E. (1961). Specific limits and distribution of Ash-throated and Nutting flycatchers. Condor 63:421-449. Close , Lanyon 1963a Lanyon, W. E. (1963a). Experiments on species discrimination in Myiarchus flycatchers. American Museum Novitates 2126. Close , Lanyon 1963b Lanyon, W. E. (1963b). Notes on a race of the Ash-throated Flycatcher, Myiarchus cinerascens pertinax, of Baja California. American Museum Novitates 2129:1-7. Close ), community-oriented studies of nest-site selection, territory size, and nesting success (Carothers et al. 1974a Carothers, S. W., R. R. Johnson, and S. W. Aitchison (1974). Populations structure and social organization of southwestern riparian birds. American Zoology 14:97–108. Close ; Stamp 1978 Stamp, N. E. (1978). Breeding birds of riparian woodland in south-central Arizona. Condor 80: 64–71. Close ; Brush Brush 1981 Brush, T. (1981). Response of secondary cavity-nesting birds to manipulation of nest-site availability. Master's Thesis, Arizona State Univ., Tempe. Close , Brush 1983 Brush, T. (1983). Cavity use by secondary cavity-nesting birds and response to manipulation. Condor 85:461-466. Close ; Seavey Seavey 1997 Seavey, J. (1997). Nest site selection and nesting success of the Ash-throated Flycatcher in south-central Washington. Master's Thesis, Univ. of Washington, Seattle. Close , Seavey 2000 Seavey, J. (2000). Nesting success of the Ash-throated Flycatcher in Washington. Wash. Birds 7:38-44. Close ), and foraging ecology (Landres and MacMahon 1980 Landres, P. B. and J. A. MacMahon. (1980). Guilds and community organization: analysis of an oak woodland avifauna in Sonora, Mexico. Auk 97:351-365. Close , Rosenberg et al. 1982 Rosenberg, K. V., R. D. Ohmart and B. W. Anderson. (1982). Community organization of riparian breeding birds: response to an annual resource peak. Auk 99:260-274. Close ), and more specific studies of nestling growth and energetics (Mock et al. 1991 Mock, P. J., M. Khubesrian and D. M. Larcheveque. (1991). Energetics of growth and maturation in sympatric passerines that fledge at different ages. Auk 108:34-41. Close ) and effects of high temperatures on nests in metal poles (Dunning and Bowers 1990 Dunning, Jr., J. B. and Jr. Bowers, R. K. (1990). Lethal temperatures in Ash-throated Flycatcher nests located in metal fence poles. Journal of Field Ornithology 61:98-103. Close ).