Gulls are a large group of about 50 species with represenatatives all over the globe and occupy a great diversity of habitats: sea coasts, lakes, rivers, cities and even deserts. Most of them are generalists and are all good swimmers, flyers and walkers. (Pons et al., 2005)
Gulls belong to the Charadrii (Gulls, Waders and Alcids) and are closely related tot the Terns (Sternidae), Skimmers (Rhychopidae) and Skuas (Stercoraiidae). Molecular studies show that Alcids (Alcidae) are members of the same clade.The taxonomy of the Gulls has been in constant review in the past. Gulls Until recently the majority of the Gulls were lumped in the genus Larus and a few other well established genera such as Rissa, Pagophila, Rhodosthetia, Xema and Creagus. This order apears to be not satisfactory considering the differences between the species groups embraced by the large genus Larus.
Several divisions have been proposed, but an extensive cladistic study by Pons et al. (2005) has led to a new taxonomic tree with a nomenclature that is strongly supported by the genetic analysis and the morphological characteristics of the diverse species groups. This nomenclature is adopted for this website.
Ten genera are presently recognized:
- 'Masked' Gulls: Chroicocephalus
- 'Masked Gulls': Saundersilarus
- Ross's & Little Gull: Hydrocoleus
- Swallow-Tailed Gull: Creagrus
- Kittiwakes: Rissa
- Arctic Gulls: Pagophila
- Arctic Gulls: Xema
- 'White headed' Gulls: Larus
- 'Band-tailed' Gullls: Larus
- 'Black-headed' Gulls: Ichtyaetus
- 'Hooded' Gulls: Leucophaeus