Mystery bird

One of the difficulties of identifying species is that there is a sexual dimorphism (Difference between male and female). Let me take the example of the mystery bird below. It looks like a sunbird or a flowerpecker.


It has an orangish pinkish beak. It has a white throat and breast. It has a yellowish back. It could be a female (dull colour coat and yellow or white breasted) or a juvenile bird.