The IRBC continues to monitor the debate on the taxonomic position of certain species and subspecies. The most controversial of these is undoubtedly the decision taken by some European ornithological bodies to recognise what were formerly regarded as two subspecies of Herring Gull, Larus argentatus michahellis and L. a. cachinnans, as a full species Yellow-legged Gull L. cachinnans (with its own subspecies L. c. michahellis in the west of its range).
Since the IRBC does not have any particular expertise in taxonomic matters, it must rely on the views and decisions of taxonomists outside Ireland for guidance on the subject. Most authorities in continental Europe now recognise Yellow-legged Gull as a full species but the more conservative view is that it is essential that we gain a better understanding of the relationships between various eastern forms and Lesser Black-backed Gull L. fuscus before splitting Yellow-legged Gull. The IRBC sees no merit in deciding which of these is the correct view until a greater degree of consensus on the matter has been reached. In the meantime, observers should bear in mind that whatever about identifying various subspecies of Herring Gull when they are at their breeding sites, assigning lone vagrants to subspecies may be much more difficult. The Committee is anxious to receive information on all birds thought to show characters of one or other of the southern cachinnans group of (Yellow-legged) Herring Gulls. Observers of such birds should be aware of the importance of proportions, structure and shape in recognising this form in addition to the well-known leg colour and darker grey upperparts. Assessment of such records may be made a great deal easier if observers are able to obtain series of photographs.