Chroicocephalus

Chroicocephalus is a genus of gulls in the family Laridae. It comprises small to medium-sized species that are often distinguished by relatively slender bills and, in many cases, a head coloration that changes with the breeding season. The genus has been the subject of taxonomic revision, with some authorities continuing to place these species in Larus, while others recognize Chroicocephalus as a distinct group based on morphological and genetic data.

Representative species include the black-headed gull (Chroicocephalus ridibundus) and the Mediterranean gull (Chroicocephalus melanocephalus). Members of the genus occupy a wide range of habitats, including coastal areas, inland lakes, and river valleys. Adults typically show pale gray upperparts and white underparts, with regional variations in head coloration. In breeding plumage, some species wear a dark hood, while others retain a pale head. Juveniles are usually mottled brown and gradually acquire adult plumage over time.

Behaviorally, Chroicocephalus gulls are opportunistic foragers, feeding on fish, invertebrates, discarded food, and occasionally eggs or nestlings. They breed in colonies on islands, coasts, or inland waters, laying typically two to three eggs per clutch in ground nests. Many populations are migratory or partially migratory, with movements linked to food availability and season.

Conservation status varies by species and region. Most species within the genus are currently listed as of least concern by major databases, though local populations may decline due to habitat loss, pollution, and changes in food resources. The taxonomy of Chroicocephalus remains a topic of ongoing study among ornithologists.