The genus
Empidonax was introduced in 1855 by the German ornithologist
Jean Cabanis to accommodate a single species,
Empidonax pusillus. This name is now considered to be a
junior synonym of
Platyrhynchos virescens that had been introduced in 1818 by
Louis Pierre Vieillot for the
Acadian flycatcher. The genus name combines the
Ancient Greek εμπις/
empis, εμπιδος/
empidos meaning "gnat" or "mosquito" with αναξ/
anax, ανακτος/
anaktos meaning "lord" or "master". A large
molecular phylogenetic study of the
tyrant flycatcher family published in 2020 found that
Empidonax was
sister to the genus
Sayornis containing the three phoebes. Most of these birds are very similar in
plumage: olive on the upper parts with light underparts, eye rings and wing bars. In the
nesting season they may be distinguished by range,
habitat and call; in other situations, particularly on
migration and in winter, it may not be possible to be sure of specific identification.
Empidonax flycatchers often flick their wings and tails rapidly.
Euler's flycatcher,
Lathrotriccus euleri and
gray-breasted flycatcher,
Lathrotriccus griseipectus were formerly placed in
Empidonax, but differ anatomically and biochemically and are now placed in the genus
Lathrotriccus. ==Species==