| 2017 | Mediterranean Gull, Queen Mother Reservoir, two adult and second-winter, 25th-26th December. (C D R Heard) |
| 2017 | Mediterranean Gull, Queen Mother Reservoir, second-winter, 16th-23rd December. (C D R Heard) |
| 2017 | Mediterranean Gull, Queen Mother Reservoir, adult, 11th December. (C D R Heard) |
| 2017 | Mediterranean Gull, Queen Mother Reservoir, adult, 9th December. (C D R Heard) |
| 2017 | Mediterranean Gull, Queen Mother Reservoir, adult, 2nd-21st December. (C D R Heard) |
| 2017 | Mediterranean Gull, Queen Mother Reservoir, first-winter, 25th November. (C D R Heard) |
| 2017 | Mediterranean Gull, Queen Mother Reservoir, adult, 12th November. (C D R Heard) |
| 2017 | Mediterranean Gull, Queen Mother Reservoir, first-winter, 22nd October. (C D R Heard) |
| 2017 | Mediterranean Gull, Queen Mother Reservoir, adult, 19th October. (C D R Heard) |
| 2017 | Mediterranean Gull, Queen Mother Reservoir, adult, 13th October. (C D R Heard) |
| 2017 | Mediterranean Gull, Eton Wick, first-winter, 12th October. (C D R Heard) |
| 2017 | Mediterranean Gull, Queen Mother Reservoir, 28th-29th September. |
| 2017 | Mediterranean Gull, Queen Mother Reservoir, first-winter, 26th September. (C D R Heard) |
| 2017 | Mediterranean Gull, Queen Mother Reservoir, first-winter, 25th-28th September. (C D R Heard) |
| 2017 | Mediterranean Gull, Queen Mother Reservoir, 31st August. |
| 2017 | Mediterranean Gull, Queen Mother Reservoir, 29th August. |
| 2017 | Mediterranean Gull, Colnbrook, adult, 13th August. (C D R Heard) |
| 2017 | Mediterranean Gull, Lower Farm GP, 2, 26th-30th July. |
| 2017 | Mediterranean Gull, Colnbrook, adult, 22nd-24th July. (C D R Heard) |
| 2017 | Mediterranean Gull, Queen Mother Reservoir, juvenile, 21st July. (C D R Heard) |
| 2017 | Mediterranean Gull, Lea Farm Lake, 18th July. (P Scudamore) |
| 2017 | Mediterranean Gull, Theale GPs, 16th July. |
| 2017 | Mediterranean Gull, Horton Brook Quarry, adult, 11th July. (C D R Heard) |
| 2017 | Mediterranean Gull, Queen Mother Reservoir, second-summer, 5th-6th July. (C D R Heard) |
| 2017 | Mediterranean Gull, Lower Farm GP, 4th July. (A B Tomczynski) |
| 2017 | Mediterranean Gull, Great Meadow Pond, 2nd July. |
| 2017 | Mediterranean Gull, Great Meadow Pond, 28th June, same as Smith's Lawn, WGP. |
| 2017 | Mediterranean Gull, Windsor Great Park, 28th June, same as Great Meadow Pond, WGP. |
| 2017 | Mediterranean Gull, Dinton Pastures CP, 27th June. |
| 2017 | Mediterranean Gull, Lea Farm Lake, 2, 26th June. * |
| 2017 | Mediterranean Gull, Queen Mother Reservoir, first-summer, 21st June. (C D R Heard) |
| 2017 | Mediterranean Gull, Lea Farm Lake, 20th June. |
| 2017 | Mediterranean Gull, Queen Mother Reservoir, adult, 19th June. (C D R Heard) |
| 2017 | Mediterranean Gull, Queen Mother Reservoir, second-summer, 17th June. (C D R Heard) |
| 2017 | Mediterranean Gull, Theale GPs, 2, 11th-12th June. |
| 2017 | Mediterranean Gull, Theale GPs, 27th May. (K E Moore) |
| 2017 | Mediterranean Gull, Moor Green Lakes, 2, 26th May to 18th June. |
| 2017 | Mediterranean Gull, Theale GPs, 23rd May. (R Crawford) |
| 2017 | Mediterranean Gull, Queen Mother Reservoir, 1st May. |
| 2017 | Mediterranean Gull, Queen Mother Reservoir, adult, 24th April. (C D R Heard) |
| 2017 | Mediterranean Gull, Theale GPs, 23rd April. |
| 2017 | Mediterranean Gull, Moor Green Lakes, 2, 22nd April. * |
| 2017 | Mediterranean Gull, Queen Mother Reservoir, adult, 17th April. (C D R Heard) |
| 2017 | Mediterranean Gull, Lea Farm Lake, 22nd March. (B T Bennett) |
| 2017 | Mediterranean Gull, Queen Mother Reservoir, adult, 10th-12th March. (C D R Heard) |
| 2017 | Mediterranean Gull, Queen Mother Reservoir, adult, 4th-14th March. (C D R Heard) |
| 2017 | Mediterranean Gull, Queen Mother Reservoir, adult, 2nd March. (C D R Heard) |
| 2017 | Mediterranean Gull, Lea Farm Lake, 20th February. (B T Bennett) |
| 2017 | Mediterranean Gull, Queen Mother Reservoir, adult, 19th February. (C D R Heard) |
| 2017 | Mediterranean Gull, Queen Mother Reservoir, 15th February. (C D R Heard) |
| 2017 | Mediterranean Gull, Queen Mother Reservoir, adult, 14th-28th February. (C D R Heard) |
| 2017 | Mediterranean Gull, Queen Mother Reservoir, 6th February. (C D R Heard) |
| 2017 | Mediterranean Gull, Queen Mother Reservoir, adult, 1st-3rd February. (C D R Heard) |
| 2017 | Mediterranean Gull, Horton Field Pits, first-winter, 24th January. (C D R Heard) |
| 2017 | Mediterranean Gull, Queen Mother Reservoir, 23rd January. (C D R Heard) |
| 2017 | Mediterranean Gull, Summerleaze GP, adult, 21st January. (C D R Heard) |
| 2017 | Mediterranean Gull, Lower Farm GP, 19th January. (N Cleere) |
| 2017 | Mediterranean Gull, Queen Mother Reservoir, 19th January. |
| 2017 | Mediterranean Gull, Queen Mother Reservoir, adult and second-winter, 17th January. (C D R Heard) |
| 2017 | Mediterranean Gull, Maidenhead, adult, 15th January. (C D R Heard) |
| 2017 | Mediterranean Gull, Queen Mother Reservoir, adult, 6th-22nd January. (C D R Heard) |
| 2017 | Mediterranean Gull, Queen Mother Reservoir, 2nd January. (C D R Heard) |
