Bonaparte's Gull on Lewis

Here is a photo Martin Scott took down my scope on 20th May at Melbost Borve on Lewis of the first summer Bonaparte's Gull, which has been hanging out for a little while. As usual, quite dainty, being 20% smaller than accompanying Black-headeds, with a much lighter flight action. Flashing white underwings very obvious in flight, with neat black trailing edge to primaries. Black tips to the outer tail feathers, white in the centre enhanced a slight diamond shape to the tail. On the deck, the pale grey nape and black bill gave quite a different look. The legs were pink, but less bright than other individuals I have seen. A smart bird.