Northern Yellow White-eye

The Northern Yellow White-eye is the only species of white-eye present in most of its distribution range, particularly in West Africa. And as it is a characteristic bird, its identification theoretically poses no problems.
The Northern Yellow White-eye lives up to its name because it is very yellow in appearance. There is no sexual dimorphism. In the adult, the upper parts are a very nuanced olive-green with yellow while the lower parts are bright yellow. The remiges, the wing covers and the rectrices are dark brown, but largely trimmed with yellow-green, which makes most of the wings and tail the same colour as the rest of the body. The head is very yellow, particularly the face, with the vertex being slightly tinted green. Characteristic of the genus, the eye is surrounded by a white eye ring of 1 to 2 mm wide. The iris is brown-honey. A thin black loral line goes from the beak to the eye ring. The black tends to darken the circle when in contact with it and to go around it under it. The beak, thin and slightly curved, is black, more or less bluish-grey at the base. The legs are black.
The immature resembles the adult with paler lower parts.
There are 7 subspecies which differ from each other only by small details, size, nuances of plumage colouration, width of the eye ring, etc. For example, the subspecies jacksoni from Kenya and Tanzania has a noticeably wider eye ring.