Bright-rumped attila
The bright-rumped attila or polymorphic attila is a small passerine bird in the tyrant flycatcher family. It breeds from northwestern Mexico to western Ecuador, Bolivia and southeastern Brazil, and on Trinidad.
Taxonomy
The bright-rumped attila was formally described in 1789 by the German naturalist Johann Friedrich Gmelin in his revised and expanded edition of Carl Linnaeus's Systema Naturae. He placed it with the flycatcher in the genus Muscicapa and coined the binomial name Muscicapa spadicea. The specific epithet is from Latin spadiceus meaning "chestnut coloured" or "date-coloured". Gmelin based his description on the "yellow-rumped flycatcher" from Cayenne that had been described in 1783 by the English ornithologist John Latham in his book A General Synopsis of Birds. The bright-rumped attila is now one of seven flycatchers placed in the genus Attila that was introduced in 1831 by the French naturalist René Lesson.Twelve subspecies are recognised:A. s. pacificus Hellmayr, 1929 – northwest MexicoA. s. cozumelae Ridgway, 1885 – Cozumel A. s. gaumeri Salvin & Godman, 1891 – Yucatán Peninsula and nearby islandsA. s. flammulatus Lafresnaye, 1848 – southeast Mexico to Belize and central north HondurasA. s. salvadorensis Dickey & Van Rossem, 1929 – El Salvador to northwest NicaraguaA. s. citreopyga – southeast Honduras and Nicaragua to west PanamaA. s. sclateri Lawrence, 1862 – east Panama and northwest ColombiaA. s. caniceps Todd, 1917 – north, central north ColombiaA. s. parvirostris Allen, JA, 1900 – northeast Colombia and northwest VenezuelaA. s. parambae Hartert, EJO, 1900 – west Colombia and northwest EcuadorA. s. spadiceus – east Colombia through Venezuela and the Guianas south to north BoliviaA. s. uropygiatus – southeast Brazil
Description
The bright-rumped attila is a large tyrant flycatcher with a big head, hooked and slightly upturned bill and upright stance. It is long and weighs. The head is olive-green streaked with black, the back is chestnut or olive, the rump bright yellow and the tail brown. The wings are dark brown with two pale wing bars and paler feather edging. The whitish or yellow throat and yellow breast are variably streaked darker. The belly is white becoming yellow near the tail. The iris is red. The sexes are similar, but young birds have a cinnamon-fringed crown and brown eyes.The plumage is very variable, but the streaking below and obvious wingbars help in distinguishing this species from others in the genus. The calls include a loud beat-it, beat-it and a plaintive ooo weery weery weery weery woo. It does not move when singing, so can be difficult to see.
Central American birds have slightly different song structures and also tend towards lighter ochre plumage independent of Gloger's Rule; they are sometimes separated as flammulated attila . Their characteristic song given at dawn has been analyzed in detail: it has a very variable number of weerys which may become weery'os, and often ends in a woo-whit; a finite-state machine has been developed to simulate this structure. However, due to the highly variable songs more data is required before the technically plausible split can be accepted; the AOU has so far refrained from formally acknowledging it.