# Chroicocephalus

Chroicocephalus is a genus of medium to relatively small gulls which were included in the genus Larus until genetic evidence published in 2005 showed that Larus as then constituted was paraphyletic. Ten species are currently accepted. An eleventh, Saunders's gull, was included until a 2022 study demonstrated that it did not belong in Chroicocephalus; it is now treated in its own genus Saundersilarus. The genus name Chroicocephalus is from Ancient Greek khroizo, "to colour", and kephale, "head".
The species range from 28 cm up to 48 cm long, with Bonaparte's gull being the smallest, and Andean gull the largest. In all species, the body and tail are white, and the upperwing pale grey; the wingtips have distinct grey, white, and black patterns important for identification. Several have distinctively brown, pale grey, or blackish-grey coloured heads in the breeding season, but some also have the head pure white like the rest of the body. The eyes are dark in some species, or with a distinctive white iris in others; the legs and bills are bright to very dark red.
Representatives of this genus are found in regions/subregions all over the world, except for Antarctica; the species are often parapatric, but with two species together in New Zealand, the Mediterranean region, parts of southern Africa, and parts of South America. Exceptionally, three species (black-headed, brown-headed, and slender-billed gulls) can occur together in parts of southwest Asia.

## Species

Genus Chroicocephalus – Eyton, 1836 – ten species :
| Common name | Scientific name and subspecies | Range | Size and ecology | IUCN status and estimated population |
| Slender-billed gull | Chroicocephalus genei (Breme, 1839) | the Mediterranean and the north of the western Indian Ocean | Size: Habitat: Diet: | LC |
| Bonaparte's gull | Chroicocephalus philadelphia (Ord, 1815) | northern North America | Size: Habitat: Diet: | LC |
| Silver gull | Chroicocephalus novaehollandiae (Stephens, 1826) Three subspecies C. n. forsteri (Mathews, 1912) C. n. novaehollandiae (Stephens, 1826) C. n. scopulinus (Forster, JR, 1844) | Australia, New Caledonia, Loyalty Islands, Tasmania, New Zealand | Size: Habitat: Diet: | LC |
| Black-billed gull | Chroicocephalus bulleri (Hutton, 1871) | New Zealand | Size: Habitat: Diet: | NT |
| Andean gull | Chroicocephalus serranus (Tschudi, 1844) | Argentina, Bolivia, Chile, Colombia, Ecuador, and Peru. | Size: Habitat: Diet: | LC |
| Brown-hooded gull | Chroicocephalus maculipennis (Lichtenstein, MHC, 1823) | Argentina, Brazil, Chile, the Falkland Islands, and Uruguay | Size: Habitat: Diet: | LC |
| Black-headed gull | Chroicocephalus ridibundus (Linnaeus, 1766) | Palearctic including Europe and also in coastal eastern Canada. | Size: Habitat: Diet: | LC |
| Brown-headed gull | Chroicocephalus brunnicephalus (Jerdon, 1840) | Tajikistan to Ordos in Inner Mongolia. | Size: Habitat: Diet: | LC |
| Grey-headed gull | Chroicocephalus cirrocephalus (Vieillot, 1818) Two subspecies C. c. cirrocephalus (Vieillot, 1818) – South America C. c. poiocephalus (Swainson, 1837) – Africa | South America and Africa south of the Sahara. | Size: Habitat: Diet: | LC |
| Hartlaub's gull | Chroicocephalus hartlaubii (Bruch, 1855) | coastline of South Africa and Namibia. | Size: Habitat: Diet: | LC |

## Fossils

* Huahine gull †Chroicocephalus utunui -French Polynesia.