By Bob Adams from George, South Africa (Grey-headed gull) [CC BY-SA 2.0 (http://creativecommons.org/licenses/by-sa/2.0)], via Wikimedia Commons
aka Grey-headed Gull
South America and Africa. Two subspecies; coastal Ecuador and Peru, coastal southern Brazil and Argentina. Much of sub-Saharan Africa breeding in areas of fresh water and dispersing widely when not breeding even as far north as Spain and Italy.
Least Concern
NBN atlas has 54 records as at end 2024. Map Here.
An adult found at Ashleworth Ham, Gloucestershire on March 29th 1996 moved to Worcestershire and spent 18th July to 27th August on Middleton Moor in Derbyshire seems the best candidate for a natural occurence. Grey-hooded Gulls are known to mix with Black-headed Gulls that are wintering in north Africa and it is possible that when the latter return north in the spring, Grey-hooded Gulls may move with them.
Zootierliste shows no current "holdings" but the species was previously kept at Bourton on the Water (Wiltshire), Cilfrew (near Swansea), Olney (Northants) and London Zoo.
Jones J. Birdwatch August 2014 pp. 42-43