A gull that gathers around watersides and visits Japan mainly in winter.
Adults have a dark-brown hood in the breeding season; otherwise the head is pale with a dark ear spot.
In southwest Sweden, the feeding map of Black-headed Gulls differed between an urban and a rural breeding colony. In a study spanning the 1990s, about 70% of the urban birds observed away from a refuse dump used lawns. At the larger rural colony, observations were spread across bare soil (43%), newly sown fields (20%) and pasture (14%).
Once chicks were being fed, the average distance to feeding areas increased from 1.6 to 2.7 km at the urban colony and from 8.4 to 9.9 km at the rural one, compared with incubation. Gulls also visited refuse dumps, but the small Skövde colony did not change in size after its dump closed. Heavy use of a food site, by itself, did not show that the colony depended on it. These observations describe two colonies in the 1990s.
IUCN Red List · Least Concern (LC) · Global species-level assessment
BirdLife International’s 2018 IUCN global assessment lists the Black-headed Gull as Least Concern (LC), with an unknown overall population trend. Regional trends differed in the evidence cited: the European population was estimated to have declined moderately from 1990 to 2013, while surveyed North American populations increased by 361% over 40 years. Those North American surveys covered less than half of the species’ range. In Europe, the assessment records the species at 43 marine Important Bird Areas and 928 EU Special Protection Areas, with site management plans and monitoring noted.