Thick-billed Siskin (Spinus) [XC336426]
by Cristian Pinto from Polylepis grove near Pachama, XV Region, Chile (song)
Thick-billed Siskin (Spinus crassirostris) [XC144992]
by Fabrice Schmitt from Carrasco, Cochabamba Department, Bolivia (call, song)
Subspecies
It has recently been proposed that this species be placed in genus Spinus or Sporagra, and revision may be appropriate, as phylogenetic analysis indicates that South American siskins are only distantly related to the two Holarctic species (Eurasian Siskin (Spinus spinus) and Pine Siskin (Spinus pinus)). Subspecies possibly intergrade; birds from west-central Peru perhaps intermediates, similar to nominate, but with smaller base of lower mandible and breast tinged olive as in subspecies amadoni.
The following 2 subspecies are recognised:
amadoni George, WG, 1964 - Andes of central to south-eastern Peru.
crassirostris (Landbeck, 1877) - Southern Bolivia, north-western Argentina and central Chile.
BirdLife International Species Factsheet