Red-rumped Bush Tyrant

The red-rumped bush tyrant (Cnemarchus erythropygius) is a species of bird in the family Tyrannidae, the tyrant flycatchers. It is found in Bolivia, Colombia, Ecuador, and Peru. == Taxonomy and systematics == The red-rumped bush tyrant was formally described in 1853 as Taenioptera erythropygia. In 1905 Robert Ridgway erected genus Cnemarchus and transferred erythropygia to it as the type specimen. It was necessary to change the specific epithet's ending to match the masculine gender of the new genus. In the 1970s some authors moved it to genus Myiotheretes; Ridgway had noted the similarity of his new Cnemarchus to that genus. A 1988 paper gave evidence that the species belonged to Cnemarchus and a 2009 study confirmed it. The red-rumped bush tyrant shares genus Cnemarchus with the rufous-webbed bush tyrant (C. rufipennis). It has two subspecies, the nominate C. e. erythropygius (Sclater, PL, 1853) and C. e. orinomus (Wetmore, 1946). == Description == The red-rumped bush tyrant is 20 to 23 cm (7.9 to 9.1 in) long. One female weighed 50 g (1.8 oz). The sexes have the same plumage. Adults of the nominate subspecies have a white forecrown that becomes a hoary gray crown. Their back is dark gray brown…