Percorrer por autor "Silva, Filipa Santos Medinas Realinho da"
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- Food choices of the Yellow-legged Gull population of Barreta Island, on anthropogenic food sources from fishing ports, fishing vessels and landfillsPublication . Silva, Filipa Santos Medinas Realinho da; Serrão, Ester; Oliveira, NunoHuman activities have caused changes in ecosystems and animal populations worldwide. These have been increasing with the human population growth and the consequent development of anthropogenic activities. One of the most affected groups of animals are marine birds yet, several opportunistic seagull populations have undergone a demographic explosion over the last decades. Gull species, such as the Yellow-legged Gull, owe part of their success to their great ability to exploit human-related food sources, namely fisheries discard and refuse dumps. The Yellow-legged Gull can widen or narrow its trophic niche according, for example, to temporal food availability. In fact, temporal fluctuations in food availability are one of the main factors shaping seabird population dynamics and foraging strategies. Understanding species' ecological responses to these fluctuations provides important information on gull populations dynamics and feeding ecology. Here, we report the food choices and foraging strategies of the Yellow-legged Gull population from Barreta Island, according to food availability at four different foraging sites in Algarve, Southern Portugal. Our results showed that the foraging strategies of this population go in line with the week/weekend cycles and precise timetable of fisheries activities and landfill-related work. This population can match its foraging schedules with human activity schedules, foraging at each study site not only when there are activities taking place and consequently food availability, but also when food abundance is higher. Furthermore, a significant proportion of individuals in this population seem to be able to predict food availability in space and time. Our results confirm the dependence of this population on fishery discards but point also to a relevant exploitation of food resources on the Sotavento landfill. These patterns of food dependency may lead to a decrease in this population after the implementation of European policies on fish discards and open-air landfill management.