Candidate mandtii Black Guillemot in Lincolnshire, UK

By Yoav Perlman mandtii Black Guillemot featured on Birding Frontiers in the past – see here and here. It also featured in Martin’s Challenge Series – Winter book. While to my understanding previous claims (e.g. East Yorkshire 2013, Cumbria 2013 and maybe a couple more) were abnormal arcticus rather than mandtii, this recent bird found by the […]