Blackheaded Gull Winter Plumage
Not really a black-headed gulls because in winters this black hood retreats and bird have a largely white head with a dark spot behind the eye.
They are Sociable,quarrelsome,noisy birds,usually seen in small groups or flocks,often gathering into large parties where there is plenty of food....as you seen in this photograph.
Parikshit Gurjar, India, Thane