A comparative study was made of Yellow-legged Gull (Larus michahellis) chick diet at six colonies on rocky islands off the southeast coast of France, and which had marked differences in their accessibility to landfills. We determined the type of foraging habitat used (landfill, other terrestrial habitats, marine habitat) and the number of foraging habitats that supplied the food in each regurgitate (one, two or three). Landfills were consistently used by gulls from the six colonies, but not always as the main foraging habitat (38% to 83% of regurgitates). For the four colonies off Marseilles (high landfill accessibility), the majority of regurgitates contained food from only one foraging habitat while, at two colonies with low landfill accessibility, the majority of regurgitates each contained food obtained from two foraging habitats. Moreover, the Principal Component Analysis performed on diet features and landfill accessibility parameters demonstrate a significant inverse correlation between landfill accessibility and foraging on terrestrial habitats. The results underlined the influence of landfill accessibility on the characteristics of the chick’s diet. Moreover, they also suggest that during chick rearing, adult gulls shift their diet from a high specialization on landfill foraging (brooding period), towards a more diversified diet, feeding their chicks by increasing the use of terrestrial habitats..