January 1978 – vol. 71, issue 1, pp 33–33 Although plumage features are important in the identification of any bird, experienced field ornithologists tend to make much use of the way that it moves, its structure and its shape--the factors that go to make u p its 'jizz'. Mystery photograph 13 (Brit. Birds 70: 544, plate 153), repeated at reduced size here, is barely more than a Silhouette, yet is easily identified. It is clearly a Grey ... This article is only available to registered users.To read more, please log in or purchase a subscription.