Yes, the pattern on head, back, underparts indicates that is a juvenile of one of the small bitterns.
Looking at photos of Yellow, Von Schrenck's and Cinnamon Bitterns, there is a clear difference in the eye-pattern between Yellow and the other two. This bird can be immediately identified as Yellow Bittern because the dark pupil is entirely encircled by the yellow iris. The other two species show a distinctive dark mark extending from behind the pupil across the iris to the edge of the eye.
This feature is mentioned in Brazil's 'Birds of East Asia'.
(Oops - I see this point was made in a recent thread on Cinnamon Bittern!!)
[ Last edited by ddavid at 20/10/2015 23:21 ]
