What situation do you want (what authority, what point in time, etc...)?
In the past, the "traditional" classification has been :
- Herring gull Larus argentatus, with sspp. argentatus, argenteus, smithsonianus and vegae;
- Yellow-legged gull Larus cachinnans, with sspp. cachinnans, michahellis, atlantis, armenicus, barabensis and mongolicus;
- LBB gull Larus fuscus, with sspp. fuscus, intermedius, graellsii, heuglini and taimyrensis.
(NB - "L. michahellis cachinnans" is a nomenclatural impossibility.)
The most frequent variation from this has been the recognition of Armenian gull Larus armenicus as an additional monotypic species (HBW, Howard & Moore, etc...).
This classification, however, has never been recognised by the BOU. Assuming the last (4th) TSC report is representative of the previous position of the BOU prior to the recent splits (? - the position of the BOU regarding several taxa unrecorded in Britain had in fact never been made clear before these splits were published...), the situation would have been :
- Herring gull L. argentatus, with sspp. argentatus, argenteus, smithsonianus, vegae, taimyrensis, heuglini, cachinnans, michahellis, atlantis, armenicus, barabensis and mongolicus;
- LBB gull L. fuscus with sspp. fuscus, intermedius and graellsii.
In their 3rd report, the BOURC-TSC separated yellow-legged and Armenian gull from this very broad herring gull, but with yellow-legged gull limited to the Mediterranean/Atlantic forms (i.e., cachinnans and the more eastern taxa were kept in the herring gull). Thus :
- Yellow-legged gull L. michahellis, with sspp. michahellis and atlantis;
- Armenian gull L. armenicus, monotypic;
- Herring gull L. argentatus, with sspp. argentatus, argenteus, smithsonianus, vegae, taimyrensis, heuglini, cachinnans, barabensis and mongolicus;
- LBB gull L. fuscus with sspp. fuscus, intermedius and graellsii.
In their 4th report, they further separated Caspian gull, and American herring gull, the latter including smithsonianus, vegae and mongolicus, and they transferred heuglini, taimyrensis and barabensis to LBB gull. Which then gives :
- Yellow-legged gull L. michahellis, with sspp. michahellis and atlantis;
- Armenian gull L. armenicus, monotypic;
- Herring gull L. argentatus, with sspp. argentatus and argenteus;
- American herring gull L. smithsonianus, with sspp. smithsonianus, vegae and mongolicus;
- Caspian gull L. cachinnans, monotypic;
- LBB gull L. fuscus with sspp. fuscus, intermedius, graellsii, taimyrensis, heuglini and barabensis.
"Baltic gull" should be Larus fuscus fuscus, indeed.
But beware that "Baltic herring gull" is a colloquial term to designate L. argentatus argentatus from the Baltic sea area (particularly from those populations where yellow legs occur quite regularly, and that have been called "L. argentatus omissus").
Laurent -