Jérôme Legrand

How Is the Diet of Yellow-legged Gull Chicks Influenced by Parents’ Accessibility to Landfills?

Abstract 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..

Colony-Site Selection Drives Management Priorities for Yelkouan Shearwater Populations

Abstract We tested whether colony-site availability could allow for an increase in the unusually small breeding populations of yelkouan shearwater (Puffinus yelkouan) on the islands of the Port-Cros National Park (France) if feral cat eradication were undertaken. Comparisons between colony and noncolony sites indicated yelkouan shearwaters preferred deep-soiled and low-outcrop–covered coastal sites. A substrate cover, light avoidance, and sea proximity model suggested that 17.5% of unoccupied sites are suitable for colony establishment. The low proportion of suitable sites currently used by yelkouan shearwaters suggests that these colonies could be refuges and that feral cat eradication will probably lead to a breeding population increase.