Myiarchus are medium-sized flycatchers with a slight bushy crest and drab plumage. The Galapagos Flycatcher is relatively small Myiarchus, and even by the standards of this genus, is a nondescript bird. It is endemic to the Galapagos Archipelago, where it is the only representative of its genus.
Although the Galapagos Flycatcher is quite similar to other species in its genus, because it is the only member of its genus ever recorded in the Galapagos Islands, it is unlikely to be confused with any other species.
The sexes are similar.
Upper parts gray-brown to olive-brown; throat and upper breast gray; belly sulfur-yellow. Primaries and secondaries olive-brown to brown, edged pale. Rump brown. Rectrices gray-brown with rufescent edging. Closed wing shows a double wing bar. Crest when folded gives head an angular shape. Iris dark brown. Ridgway (1907) indicated that juveniles also have cinnamon-rufous edgings to the inner webs of the rectrices, and the tips of the middle and greater wing coverts are buffy.
Swarth (1931) suggested that the annual molt had ended by early June, but post-juvenal molt ended up to a month later.
Bill dark brown / horn, with base of mandible pinkish. Tarsi gray.
A smallish Myiarchus. Ridgway (1907) gives measurements for males averaging 14.2 cm in length (range 13.5 - 15.3 cm), wing 7.1 cm (range 6.7 - 7.4 cm), tail 6.3 cm (range 5.9-6.6 cm), exposed culmen 16.2 mm (range 15.5-17.0 mm), tarsus 21.7 mm (range 21.0-22.5 mm), and middle toe 9.9 mm (range 9.5-10.5 mm). Females average length is 14.4 cm (range 13.0 - 15.4 cm), wing 6.8 cm (range 6.4 - 7.4 cm), tail 6.1 cm (range 5.6-6.6 cm), exposed culmen 15.3 mm (range 14.5-16.0 mm), tarsus 21.2 mm (range 20.5-22.0 mm), and middle toe 10.0 mm (range 9.5-10.5 mm).
Additional linear measurements are provided by Swarth (1931) and Lanyon (1978).
Mass: mean 14.7 ± 1.2 g, (range 12-18.5 g, n=22, sexes combined; Dunning 2008).