White-crested Tyrannulet (Serpophaga subcristata) [XC749004]
by Mateus Gon\u00e7alves Santos from Mar del Tuy\u00fa, Partido de La Costa, Buenos Aires, Argentina (song)
White-crested Tyrannulet (Serpophaga subcristata) [XC335234]
by Ricardo Jos\u00e9 Mitidieri from Itatiaia National Park - Agulhas Negras road, Brazil (call)
Subspecies
Taxonomic status controversial. Sometimes considered conspecific with White-bellied Tyrannulet (Serpophaga munda), but the two differ in plumage, also slightly in voice, and in Argentina are narrowly parapatric with limited hybridization. Further study is required.
The following 2 subspecies are recognised:
subcristata (Vieillot, 1817) - Bolivia (from northern La Paz) and southern Brazil (southern from southern Mato Grosso) south through Paraguay to Argentina (south to northern Chubut).
straminea (Temminck, 1822) - South-eastern Brazil (southern Piauí and Bahia south to Rio Grande do Sul) and Uruguay.