Courtship feeding between Yellow-legged Gull Larus cachinnans and Herring Gull L. argentatus in the Western Mediterranean

Several species of large white-headed gulls, genus Larus, often hybridize freely where they occur sympatrically (Ingolfsson 1987, Pierotti 1987, Spear 1987, Pierotti & Annett 1993). In the Ebro Delta (Ebro Delta National Park, 40