This female Lesser/Scaup/Tufty like duck seems to be lacking a nail on it's beak, which also has pale edges. Difficiency or Lesser Scaup influence? It has a dark back which is better for Tufted, but the beak is quite broad. The nictating membrane is clearly in view, so eye colour can't be discerned unfortunately. Just the one picture taken. Any help would be great. Thanks very much in advance.