This common inhabitant of forest edge and lowland riparian, thorn, second-growth, and columnar-cactus woodlands from the southwestern United States to northwestern Costa Rica is also widely distributed in eastern South America peripheral to Amazonia. Populations that breed in the United States and northern Mexico are migratory, moving south into areas of southern Mexico and Central America, where the species also occurs as a permanent resident. Likewise, southernmost South American populations withdraw northward during the austral winter. In Arizona and northern Sonora, Mexico, breeders can occur in 2 radically different habitats: mature riparian forest and columnar-cactus woodland. Thus, overall habitat structure appears to be less important than the availability of relatively large trees or cacti and their associated woodpecker holes or natural cavities used for nesting. Vocally conspicuous on its breeding grounds, this species is otherwise rather shy, favoring canopy strata, where it mainly forages by sallying to take arthropods from foliage. In migration and winter, the species is partly frugivorous.
Before 1983, North American and Central American populations were known as Wied's Crested Flycatcher ( American Ornithologists' Union 1998a ). Distribution of the 7 currently recognized subspecies is complex, and includes migratory and sedentary mainland and insular populations, and both between- and within-subspecies distributional gaps. Boundaries between adjoining subspecies can be either abrupt (with few or no intermediate-plumaged individuals) or broad (with many intermediates). Despite these seemingly incongruous aspects of the species' status and distribution, geographic variation in appearance is only slight, and perhaps more importantly, vocalizations show even less geographic variation. Among the relatively similar-looking species of Myiarchus, voice plays a dominant role in how individuals recognize their own kind.
Two forms are widespread in Mexico and have limited distributions in the southwestern United States. The Pacific-slope subspecies (M. t. magister) is the largest in body size of any taxon in the genus Myiarchus, and it is the form most commonly depicted in North American field guides. The smaller subspecies of the Gulf-Caribbean slope (M. t. cooperi) is almost identical in size and proportions to the Great Crested Flycatcher (M. crinitus), and it is closer in size to the Ash-throated Flycatcher (M. cinerascens). As a result, there is considerable potential for misidentifications among these species.
For such a relatively ubiquitous bird of the American Tropics, there is an amazing lack of published studies dedicated exclusively to the natural history of this species. Except for thorough analyses of morphological and vocal systematics, mainly by Lanyon ( Lanyon 1960b , Lanyon 1963a , Lanyon 1967 , Lanyon 1978 ), the life history of the Brown-crested Flycatcher is poorly known or unknown, particularly regarding physiology, self-maintenance and social behavior, and the late stages of breeding biology (incubation onward). The logistical difficulty of studying a canopy-dwelling, relatively secretive, cavity-nesting species may be partly responsible for this neglect.