December 1992 – vol. 85, issue 12, pp 647–649 It is October in southwest Britain and anything can turn up. You are being bombarded by vagrants from all points of the compass when you come upon this unfamiliar bird in some poplars Populus (plate 267, repeated here in black-and-white). You realise immediately that it looks odd, but cannot work out why. Stop, slow down and take a deep breath. Now, let us work through it logically. Compariso... This article is only available to registered users.To read more, please log in or purchase a subscription.