The BOURC Taxonomic Sub-committee (TSC) recently published recommendations for the taxonomy of the Herring Gull and Lesser Black-backed Gull complex (Sangster et al. 2007). Six species were recognised: Herring Gull Larus argentatus, Lesser Black-backed Gull L. fuscus, Caspian Gull L. cachinnans,Yellow-legged Gull L. michahellis, Armenian Gull L. armenicus and American Herring Gull L. smithsonianus.This paper reviews the evidence underlying these decisions and highlights the remaining areas of uncertainty where taxonomic revision may be required in future.