Whilst this has two wing bars and looks like it has dark legs, this is in fact an Arctic Warbler. The left leg is in shadow and therefore looks dark, whereas the right leg is paler and more Arctic like in colour. The supercilium terminates before the bill (on Greenish it reaches the bill base and sometimes forms a small pale area on the forecrown), the primary projection is long, and the sixth primary, (the outer edge of which is clear) does not have an emargination which is a critical in the hand difference between Arctic and Greenish Warblers.
