Black-billed Nightingale-Thrush

The black-billed nightingale-thrush (Catharus gracilirostris) is a species of bird in the family Turdidae, the thrushes and allies. It is found in Costa Rica and Panama. == Taxonomy and systematics == The black-billed nightingale-thrush was originally described in 1865 with its current binomial Catharus gracilirostris. The black-billed nightingale's further taxonomy is unsettled. The IOC, AviList, and BirdLife International's Handbook of the Birds of the World assign it three subspecies: the nominate C. g. gracilirostris (Salvin, 1865), C. g. accentor (Bangs, 1902), and C. g. bensoni (Griscom, 1924). The Clements taxonomy recognizes two by including bensoni within accentor. This article follows the three-subspecies model. == Description == The black-billed nightingale-thrush is about 15 cm (5.9 in) long and weighs about 20 g (0.71 oz) The sexes have the same plumage. Adults of the nominate subspecies have a slate-gray forecrown, an olive-brown crown, and a slate-gray face. Their upperparts, wings, and the upper side of their tail are olive-brown. Their throat is whitish, the middle of their lower belly light gray to whitish, and the rest of their underparts slate-gray with an olivaceous band across the breast. They have a dark brown iris, a black bill, and dark gray legs and feet.…