About Myioborus melanocephalus (Tschudi, 1844)
The spectacled whitestart (Myioborus melanocephalus) generally weighs 10 to 13 grams, and measures 13 to 13.5 centimeters (5.1 to 5.3 inches) in total length. This species has a black face and crown, with grey nape and back. Its tail is mostly black, though the outermost tail feathers have some white markings. The underbody, from the throat down to the base of the tail, is yellow, while the undertail coverts are white. The beak and legs are black, and the iris is dark. Adult males and females have identical plumage and cannot be distinguished visually. Juveniles have grey head and back, and paler yellow underparts than adults. The species gets its common name from prominent yellow "spectacles" on the face, formed by a yellow ring around the eye and a yellow stripe running under the lores. Compared to the nominate subspecies Myioborus melanocephalus melanocephalus, the subspecies M. m. bolivanus is slightly smaller, and has paler coloration on its underparts. The black facial region is more extensive in M. m. malaris. M. m. griseonuchus also has similarly extensive black on the face as M. m. malaris, and additionally has a tiny patch of rufous brown on its crown. M. m. ruficoronatus has a larger rufous patch on the crown, but matches the nominate M. m. melanocephalus in all other aspects of its coloration.
