Henry Eliot Howard, The British Warblers A History with Problems of Their Lives… (1908)
“ The sides of the face and neck are light olive green tinged with grey, each small feather on the cheek being furnished with a whitish yellow centre line. The upper parts of the wings are dark brownish grey. The least wing-coverts are tinged with olive green and have very narrow light margins; the medium and greater secondary coverts are tipped with white, forming two distinct bands on the wing. The bastard wing and greater primary coverts are of the same colour as the wing, but not tipped with the whitish colour. ”
