Serpophaga tyrannulets are a tricky bunch, both in terms of taxonomy and identification, both of which are unresolved. This individual is different to the bird in the previous three photos in this sequence. This bird is of the form 'subcristata', although its greyer mantle and lack of yellow underparts recall the form that is called 'munda' (but may be conspecific with subcristata). The bird in photos 1-5 in this sequence appears to be a classic 'subcristata'.