Terns and gulls ara species with dynamic ecology, adaptable to the particular circumstances of each breeding season. However, some of their populations have significantly decreased during last years, as well as various episodes of local extinction at different points of the territory.
Although some causes of this phenomenon are known (human nuisances, predator densities, etc.), few studies have focused on assessing the availability of trophic resources, as well as frequent fluctuations or changes in the measurement of stocks.
Where do terns and gulls feed at Delta? Do they find enough resources? How about the state of their populations? Are they endangered? What we can do to improve them? Juan Bécares and Marcel Gil-Velasco from Cory’s try to answer all these questions.