The UK400 Club does NOT recognise Feral Pigeon nor Scottish Parrot Crossbill, the latter considered an isolated form of Parrot Crossbill. Slender-billed Curlew is also not accepted (the most recent claim is considered to relate to Eurasian Curlew).

Pacific Diver (considered distinct from Black Throated Diver)
Masked Booby (1-2 records)
Atlantic Yellow-nosed Albatross (2 records of one individual)
European White Pelican (several records)
American Least Bittern (1 record)
Chinese Pond Heron (Category D)
Sacred Ibis (Category C vagrant from population in France)
Greater Flamingo (several records considered genuine vagrants)
Chilean Flamingo (Category C vagrant from feral population in Germany)
North American Whistling Swan (considered distinct from Bewick’s Swan)
Ross’s Snow Goose (numerous records, vagrants from North America where species has undergone 71% increase in population; record 4 birds in 2007/8 winter)
Greenland White-fronted Goose (considered distinct from Eurasian/Pacific)
Tundra Bean Goose (considered distinct from Taiga Bean Goose)
Pale-bellied Brent Goose and Black Brant (both considered specifically distinct from Dark-bellied Brent Goose)
Ruddy Shelduck (mix of vagrants and Category C vagrants from Russia and elsewhere)
Bar-headed Goose (Category C vagrant from feral populations in The Netherlands)
North American Wood Duck (1 record - vagrant male in North Sea)
Falcated Duck (numerous records - Category D)
Marbled Duck (numerous records, clear pattern of vagrancy)
Baikal Teal (several records, one at least on Category A)
Cinnamon Teal (1 record considered vagrant - Outer Hebrides)
White-winged Scoter (1 record - NW Scotland)
Hooded Merganser (numerous records, clear pattern of occurrence)
White-headed Duck (numerous records including influx years; clear pattern of occurrence)
Eurasian Black Vulture (1 record - considered Vagrant)
North American Bald Eagle (1+ records)
Booted Eagle (at least 4 records - considered vagrant)
North American Hen Harrier (considered distinct from Hen Harrier)
Red-shouldered Hawk (1 ship-assisted vagrant)
Saker (records under consideration for recategoristaion - currently in Category E)
Lady Amherst’s Pheasant (Category C - 7 males still survive)
Hudsonian Whimbrel (considered distinct from Eurasian Whimbrel)
Caspian Gull (considered distinct from Herring Gull)
Thayer’s Gull (5 accepted records from Ireland; at least 4 others under review)
North American Least Tern (1 record; considered distinct from Little Tern)
Elegant Tern (at least 5 records)
North American Black Tern (6+ records mainly from Ireland; considered specifically distinct from Black Tern)
Eurasian Eagle Owl (population of 44 pairs in UK of unknown provenance; accepted to Category D)
White-rumped Swift (single record from Ireland)
Monk Parakeet (status being reviewed, feral population currently just under 100 individuals)
Middle-spotted Woodpecker (1 record, East Kent)
Northern Flicker (ship-assisted vagrant to Ireland)
White Wagtail (considered distinct from Pied Wagtail)
Amur Wagtail (considered distinct from Pied Wagtail; 3 vagrant records)
Black-headed Wagtail (numerous records; considered distinct from Yellow Wagtail)
Eastern Yellow Wagtail (10+ records; considered distinct from Yellow Wagtail)
Eastern Common Nightingale (3 records; taxonomic status currently under review)
Siberian and Caspian Stonechats (both vagrants and both considered specifically distinct from Common Stonechat)
Bicknell’s Thrush (vagrant on Scilly 1 record; considered distinct from Grey-cheeked Thrush)
Red-throated Thrush (1 record in Essex; considered distinct from Black-throated Thrush)
Naumann’s Thrush (3 records; considered distinct from Dusky Thrush)
Desert Lesser Whitethroat (10+ records; considered distinct from Lesser/Siberian Lesser Whitethroats)
Eastern Subalpine Warbler (regular vagrant; considered distinct from Western/Moltoni’s Subalpine Warblers)
Sykes’s Booted Warbler (8+ records; considered distinct from Booted Warbler)
Siberian Chiffchaff (considered distinct from Common/Scandinavian Chiffchaffs)
Two-barred Greenish and Green Warbler (both vagrants and both considered specifically distinct from Greenish Warblers)
Asiatic Brown Flycatcher (2 vagrant records)
Mugimaki Flycatcher (1 record - considered vagrant)
House Crow (ship-assisted records to Ireland)
Daurian Starling (2 vagrant records)
Mealy, Greenland and Scandinavian Arctic Redpolls (5 species recognised by UK400 Club but may all relate to one North-south cline of single species)
Pine Siskin (ship-assisted record)
Field Sparrow (ship-assisted record)
American Goldfinch (ship-assisted record in Ireland - still under review)
Rusty Blackbird, Yellow-headed Blackbird (several records)
Brown Thrasher (ship-assisted record)
Spotted Towhee (ship-assisted record)
Red-headed Bunting (numerous records; clear pattern of summer vagrancy)