The Yellow-breasted Chat is the largest wood-warbler. Its placement in the family Parulidae, however, has been questioned at times because of its many traits atypical of parulids—large size, eclectic vocal repertoire, behavior, and certain anatomical features. Molecular data, however, support its traditional classification in the Parulidae.
Over its extensive range, this chat is found in low, dense vegetation without a closed tree canopy, including shrubby habitat along stream, swamp, and pond margins; forest edges, regenerating burned-over forest, and logged areas; and fencerows and upland thickets of recently abandoned farmland. Breeding populations in eastern North America probably increased following extensive logging and fragmentation of forests during the late nineteenth and early twentieth centuries and abandonment of marginal cropland in the middle third of the twentieth century. Populations in some of these areas are now declining, as mature forest replaces more open, brushy habitat. There is evidence of increases in some western populations despite loss of riparian habitat there.
Although its geographic range is broad, this bird is frequently overlooked and seldom seen. Contributing to this elusiveness is the structure of its brushy habitat, which is often described as impenetrable and unattractive. The most important factor, however, is its skulking, secretive nature. Nonetheless, the chat's extensive vocal repertoire—variously described as composed of whistles, rattles, catcalls, and grunts—makes the male's presence easy to document early in the breeding season. Late in the breeding season, during migration, and on the wintering grounds, the non-singing birds are difficult to detect.
Although the Yellow-breasted Chat has a broad geographical range, distinctive vocalizations, and often high breeding densities, there are few detailed studies of its biology. Controversy over the taxonomic placement of the species has inspired comment over the years (see review by Sibley and Ahlquist 1982c ), but the pioneering description of general behavior and breeding biology by Petrides ( Petrides 1938 ) was not expanded upon until Dennis ( Dennis 1958 , Dennis 1967a ) described aspects of breeding ecology and fall migration. These works were followed by studies of demography ( Thompson and Nolan 1973 , Thompson 1977b , Burhans and Thompson III 1999 , Ricketts and Ritchison 2000 ) and of behavior and vocalizations (for example, Ritchison 1988a , Burhans and Freeman 1997 , Dussourd 1998 , Schadd and Ritchison 1998 ) carried out in the eastern and midwestern parts of the breeding range.