Swainson's Flycatcher (Myiarchus swainsoni) [XC699907]
by Guillermo Treboux from La Bolsa, Salto Department, Uruguay (song)
Swainson's Flycatcher (Myiarchus swainsoni) [XC460091]
by Renan Betzel from Bara\u00fana, Rio Grande do Norte, Brazil (call)
Subspecies
A taxonomically difficult complex and in need of revision that carefully integrates molecular and morphological data. Nominate subspecies is larger and/or darker than most others, also differs vocally, and phylogenetic analysis of mitochondrial DNA indicates that it is not closely related to other subspecies; almost certainly represents a separate species. From mtDNA studies, other subspecies appear extraordinarily closely related to each other (although phaeonotus not included in samples), and also closer to Dusky-capped Flycatcher (Myiarchus tuberculifer) and Sad Flycatcher (Myiarchus barbirostris) than to all other taxa in genus (as mirrored in voice-playback experiments). Hypothesis that variation between subspecies pelzelni and ferocior (possibly including phaeonotus) is clinal, with increase in size and increasingly paler upperparts from north to south, needs to be tested.
Birds from northern sandy savanna of Surinam described as a further subspecies, albimarginatus, but characters appear attributable to fresh-plumaged intergrades between phaeonotus and pelzelni.
The following 4 subspecies are recognised:
phaeonotus Salvin & Godman, 1883 - Tropical and subtropical zones of south-eastern Venezuela, western Guyana and adjacent northern Brazil (upper R Negro and R Branco).
pelzelni von Berlepsch, 1883 - Southern and eastern perimeter of Amazon Basin south to south-eastern Peru, northern Bolivia and south-central Brazil (south to Mato Grosso, southern Goiás and Minas Gerais).
swainsoni Cabanis & Heine, 1859 - Breeds south-eastern Paraguay and south-eastern Brazil (Sío Paulo, Rio de Janeiro) south to extreme north-eastern Argentina (Misiones) and Uruguay; migrates to northern South America, from eastern Colombia, western Venezuela and Trinidad east to north-eastern Brazil (Paraíba).
ferocior Cabanis, 1883 - Breeds south-eastern Bolivia, western Paraguay and Argentina (south to La Pampa and Buenos Aires); migrates to Amazon Basin as far northern as southern Colombia.
BirdLife International Species Factsheet