Subspecies olivaceum.
This taxon must surely have happened to end up in the wrong species! There are hardly any similarities between this and the taxon in the highlands and west. Different colours, shape, habitat and the sounds are completely different. One of the most obvious splits in Ecuador...
Totally agree with your comment! I looked at it and thought, "But that's not a Southern Beardless Tyrannulet". Thanks for posting the image and giving your comments.