Who do you think is feeding who? It looks like the bigger bird is giving a gulp to the smaller one, when in fact it is the reverse! The bigger bird is a young emerald cuckoo, which probably just left the nest, but is still unable to feed itself. The smaller bird is the surrogate mother which is probably having a hard time feeding this big monster. I was alerted at the camp by the cries of the young cuckoo and was lucky enough to be at the right place with my camera when the mother arrived.