White-crested Tyrannulet (Serpophaga subcristata) [XC427948]
by Franco Vushurovich from Trilha do Portal do C\u00e9u, Patrimonio da Penha-ES, Esp\u00edrito Santo, Brazil (canto)
White-crested Tyrannulet (Serpophaga subcristata) [XC747819]
by Pablo Adri\u00e1n Otero from Soldini, Rosario, Santa Fe, Argentina (call, song)
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.