Possibly a Lance-tailed Manakin (Chiroxiphia lanceolata) or a Long-tailed Manakin (C. linearis). I think that Blue-backed is another common name for Lance-tailed Manakin.
@Summer Tanager Blue-backed Tanager is C. pareola - it may be another common name for Lance-tailed but it is technically incorrect. Also both species you suggest have longer tails, and this individual shows none at all. It is possible for the elongated feathers to be missing, but it matches Blue-backed by appearance here.
