Summary:

This paper reviews the literature, reports on field experience with a number of the Atlantic forms and attempts to determine whether there is such a taxon as an Atlantic Yellow-legged Gull. The conclusions reached must be regarded as preliminary in view of the variation found and the complexity of the relationship between the various forms. The main form, called here the Dark Atlantic, is found on the Atlantic Islands (Azores, Madeira and Canaries) and on the Atlantic coasts of north-west Africa and the Algarve in Portugal. Another paler form, the Cantabrican, is found in the eastern part of the northern Atlantic coast of Spain. There is a cline between the Dark Atlantic and Cantabrican forms through western Portugal and north-west Spain. Studies continue on the forms in the intersection zone between the Dark Atlantic form and Mediterranean michahellis in Andalucia, Gibraltar and north Morocco.