Sibilant sirystes
The sibilant sirystes is a species of bird in the family Tyrannidae, the tyrant flycatchers. It is found in Argentina, Bolivia, Brazil, and Paraguay.
Taxonomy and systematics
The sibilant sirystes was originally described as Muscicapa sibilator, mistakenly placing it with the Old World flycatchers. In 1860 the genus Sirystes was erected for it. Some authors included the genus in family Cotingidae but by the 1930s it was placed in its current family. The sibilant sirystes was eventually expanded by what are now the white-rumped sirystes and Todd's sirystes ; some systems also included what is now the Choco sirystes. The combined species was simply called "sirystes". As a result of a study published in 2013, "sirystes" was split into four species.The sibilant sirystes has two subspecies, the nominate S. s. sibilator and S. s. atimastus.
Description
The sibilant sirystes is long and weighs about. The sexes have the same plumage. Adults of the nominate subspecies have a black crown with a slight crest. The rest of their face is slate gray. Their nape and back are mottled gray with an olivaceous cast in most individuals and their rump has a gray wash, with white tips in the northern part of its range. Their wings are blackish with wide gray edges on the coverts and inner flight feathers. Their tail is long, blackish, and has a square tip. Their throat and breast are gray that becomes grayish white on the belly. Subspecies S. s. atimastus has yellowish tips on the rump feathers, a pale ashy throat, and a white breast and belly. However, the differences between the two subspecies appear to be clinal. Juveniles resemble adults with a faint overall buffy wash. Both subspecies have a dark reddish brown iris, a black bill, and blackish legs and feet.Distribution and habitat
The nominate subspecies of the sibilant sirystes has by far the larger range. It is found in Brazil in an area roughly bounded by central Amazonas and northeastern Pará, narrowing southward through Mato Grosso and Goiás, and then widening east to Minas Gerais and Espírito Santo and continuing south to northern Rio Grande do Sul. Its range continues into eastern Paraguay and northern Argentina to northeastern Corrientes Province. It also occurs as a non-breeder in Bolivia. Subspecies S. s. atimastus is found only in the vicinity of Chapada dos Guimarães in Mato Grosso.The sibilant sirystes inhabits several forested landscapes including primary forest, mature secondary woodland, riparian forest, and dry cerradão forest. It almost always keeps to the forest canopy. In elevation it reaches at least in Brazil but may occur as high as.