Comparative analysis of the Yellow-legged Gull's (Larus michahellis (Naumann, 1840)) trophic ecology in two colonies of the Central Coast of Algeria

摘要

The Yellow-legged Gull's diet (Larus michahellis) was studied by analyzing 118 pellets of adults collected in two colonies of the Algerian Central coast. This study has resulted in the identification of 89 food items. The dietary diversity (73 food items) of the Yellow-legged Gull on the Aguelli Island was found to be richer than that on the Tigzirt Island where only 44 food items were identified. It is surprising that the proportion of inorganic remains in pellets of Yellow-legged Gull adults on theAguelli Island (33.24%) is the largest, followed by the food category represented by terrestrial prey (20.74%), and vegetation remains ranking last (20.45%). Meat remains (31.95%) are strongly represented in the composition of the Yellow-legged Gull's pellets in the colony of the Tigzirt Island. As far as marine vertebrates are concerned, their share in the diet accounts for about 21.3%, while that of plant remains for 19.5% and ranks third. With regard to the foraging habitat, it appears that Yellow-legged Gulls of Reghaia and Tigzirt coasts seem to be dependent on garbage dumps. This foraging habitat dominates with frequencies of 59.76 and 66.76% for Tigzirt and Aguelli islands, respectively. In the diet of Yellow-legged Gulls on the Tigzirt Island,foods from the marine environment rank second, while in the diet of these seabirds on the Aguelli Island, this place is held by food items from the terrestrial environment.