List of British Birds
| African Grey Parrot | Psittacus erithacus | |
| Aleutian Tern | Onychoprion aleutica | |
| Allen's Gallinule | Porphyrula alleni | |
| Alpine Accentor | Prunella collaris | |
| Alpine Swift | Apus Melba | |
| American Bittern | Botaurus lentiginosus | |
| American Black Duck | Anas rubripes | |
| American Coot | Fulica americana | |
| American Golden Plover | Pluvialis dominica | |
| American Kestrel | Falco sparverius | |
| American Wigeon | Anas americana | |
| Ancient Murrelet | Synthliboramphus antiquus | |
| Aquatic Warbler | . | |
| Arctic Redpoll | Carduelis hornemanni | |
| Arctic Skua | Stercorarius parasiticus | |
| Arctic Tern | Sterna paradisaea | |
| Arctic Warbler | Phylloscopus borealis | |
| Ascension Frigatebird | Fregata aquila | |
| Asian Desert Warbler | Sylvia nana | |
| Audouin's Gull | Larus audouinii | |
| Avocet | Recurvirostra avosetta |