The first of two main contributions to this issue is a scholarly and detailed account of the identification, taxonomy and distribution of the Palearctic House Martin taxa. It will no doubt please many keen birders who have stumbled upon a House Martin buzzing around their east-coast patch in the late autumn and wondered about the possibility that the bird originated from a long way east. In mid November 2018, I was grateful to Paul Leader for confirming that, in my case, I had simply photographed the latest-ever Western House Martin in Shetland.
A plea from readers for more identification papers in BB is something that we have been well aware of in recent years. Nowadays, however, and especially in relation to the many cryptic taxa at the cutting edge of field identification, there is seldom a simple ‘eureka moment’ when it comes to genuine advances in ID. Instead, potential new criteria tend to be floated tentatively online, in blogs and social media, where there is effectively unlimited space for photographs, video, sound recordings, etc., and this begins an iterative cycle of feedback and further progress, which may be slow (and may go nowhere) but allows many people to contribute and test ideas. Sites such as the much-missed Birding Frontiers provide a great forum to highlight and disseminate speculative pointers on a wide range of subject matter; in contrast, the demands of a peer-review system and the constraints of paper format tend to be off-putting for potential authors. We have discussed and debated this at length in recent years and (particularly now that our digital format, BB Online, has been settled) our aim is to bring more ID material to readers – material that has still gone through a peer-review process but which may not necessarily have all the answers to, or be the last word on, a thorny ID subject. Watch out for a paper in the next issue of BB that brings this approach to the identification of Northern Shrike Lanius borealis in the Western Palearctic.
64 BB eye: Vulture conservation – no excuses for failure
67 News and comment Adrian Pitches
72 The identification, taxonomy and distribution of Western, Siberian and Asian House Martins Paul Leader, Geoff Carey and Manuel Schweizer
97 Insights from colour-ringing Little Terns across Britain, Ireland and the Isle of Man Linda Wilson, Susan Rendell-Read, Chris Brown, George Candelin, Henry Cook, Steve Hales, Leigh Lock, Steve Newton, David Norman, Louise Samson, Jack Slattery, Leah Williams and Mark Bolton
117 The BB/BTO Best Bird Book of the Year 2020 Stephen Menzie, Gill Birtles, Tom Cadwallender, Ian Carter, Hazel McCambridge and Roger Riddington
124 Recent reports