Brown-headed Gulls in non-breeding plumage in the Bang Poo Nature Reserve in Samut Prakan, where they winter between October and February.

This gull is similar to and often mixes with Black-headed Gulls (fig.), but is slightly larger, bulkier, thicker-billed and thicker-necked. The birds with some additional brown-white pattern on the wing edges are in first winter plumage.