Sooty-faced Finch

The sooty-faced finch (Arremon crassirostris) is a species of bird in the family Emberizidae, the New World sparrows. It is found in Colombia, Costa Rica, and Panama. == Taxonomy and systematics == The sooty-faced finch has a complicated taxonomic history. It was formally described in 1865 with the binomial Buarremon crassirostris. In 1898 Robert Ridgway erected a new genus for it, Lysurus. He also assigned what is now the olive finch (then Buarremon castaneiceps, now Arremon castaneiceps) to the new genus. In 2008 taxonomists began merging Lysurus into Arremon. The sooty-faced and olive finches are now treated as sister species. The sooty-faced finch is monotypic. == Description == The sooty-faced finch is 15 to 17 cm (5.9 to 6.7 in) long and weighs 37 to 40.5 g (1.3 to 1.4 oz). The sexes have the same plumage. Adults have a rusty crown and a white down-sweeping "moustache" on an otherwise blackish gray head and nape. Their upperparts are dark olive-green and their wings and tail a slightly browner olive-green. Their upper breast, sides, and flanks are dark olive-green and their lower breast and belly yellow. They have a dark brown or chocolate-brown iris, a dark gray maxilla, a pale yellow…