First-year Movements of Yellow-legged Gull (Larus michahellis lusitanius) from the Southeastern Bay of Biscay

Information on when and where the Yellow-legged Gull (Larus michahellis lusitanius) population breeding in northern Iberia moves throughout the year is lacking. Here, distances and directions of gull movements during their first year of life were elucidated. Data on 2,776 sightings of 728 out of 2,421 gulls banded as chicks in the southeastern Bay of Biscay were analyzed. Overall, most (69.2%) gulls were found less than 50 km from their natal colonies and practically all gulls (95.9%) were found along the coast of northern Iberia, confirming the low mobility of this Yellow-legged Gull population. Distances at which gulls were found did not vary with time, suggesting that stable feeding resources exist across the area used by the population. Received 29 January 2010, accepted 24 March 2010.