Slender-billed Gull

The Slender-billed Gull breeds in localised populations throughout the Mediterranean basin, West Africa, the Middle East, and Asia Minor and Central Asia. In Portugal, this gull is primarily a coastal passage migrant. In recent years, on the Mainland, there has been a gradual increase in the number of records and individuals of this species. There are no known sightings of the Slender-billed Gull in the archipelagos of the Azores and Madeira. After breeding, some populations disperse mainly to areas bordering their breeding territories (as is the case with the Iberian populations). In Portugal, the species has a very localised distribution in the southern half of the Mainland, particularly in the eastern Algarve, with most records being made in the areas of Castro Marim and Tavira, where the species currently appears to be a regular visitor (Catry et al. 2010a). The birds arriving in Portugal are likely to originate from the nearest breeding areas, such as the Guadalquivir River marshes, and from other Spanish and Mediterranean colonies (Catry et al. 2010a). Most sightings of this gull in Portugal are not made in a marine environment, but rather in salt pans and in estuarine or coastal lagoon areas. During the marine censuses underpinning this atlas, the species was not detected. Known sightings are concentrated mainly during the pre-breeding migration period (mid-March to mid-May) and post-breeding migration period (June to October) (Catry et al. 2010a), sometimes involving flocks of dozens of individuals (CPR).

Autor

Meirinho et al. 2014