The latest (fourth) report of the Taxonomic Sub-committee of the BOU Records Committee has finally recognised American Herring Gull and Caspian Gull at the species level.
The report states:
"We recommend recognition of the following species to better reflect recent advances in knowledge of the evolution and systematics of large gulls:
• Caspian Gull Larus cachinnans (monotypic)
• Lesser Black-backed Gull Larus fuscus (polytypic, including fuscus, intermedius, graellsii, heuglini, taimyrensis, barabensis)
• American Herring Gull Larus smithsonianus (polytypic, including smithsonianus, vegae, mongolicus)
• Yellow-legged Gull Larus michahellis (polytypic, including michahellis, atlantis)
• Armenian Gull Larus armenicus (monotypic)
• Herring Gull Larus argentatus (polytypic, including argentatus, argenteus)"
Caspian Gull, Derbyshire © Steve Mann, from the surfbirds galleries
GEORGE SANGSTER, J. MARTIN COLLINSON, ALAN G. KNOX, DAVID T. PARKIN, LARS SVENSSON (2007) Taxonomic recommendations for British birds: Fourth report Ibis 149 (4), 853–857.