Reduction of variability of individual colonization programs in black-headed gulls (Larus ridibundus) leads to diminished reproductive success

摘要: The study is devoted to the problem of adaptive significance territorial antagonism in colonial birds. Many them are characterized by a high intensity and diversity demonstrations, along with tolerance each other tendency aggregate. Here we consider effects behavior on viability breeding colony. We analyze black-headed gull two colonies formed under impact short-term temperature fall 2008, which resulted 7-day shift timing egg laying. Compared at same reservoirs, one 2007 2009, number nests their density 2008 were much smaller, whereas duration settling, nest growth, average size territories did not change. body weight adult birds during incubation was stable throughout all years; however, correlations typical for 2009 (negative between female mass date clutching start positive masses parents) absent, suggesting that assortative mating territory case 2008. clutch, egg, hatching sizes smaller while mortality due attacks aerial predators higher than years. In started egg-laying first 5 days after appeared colony (pioneer settlers) larger others (the so-called followers) produced offspring. These differences observed According our data, cold weather, some abandoned nesting sites sick, but they mostly behaved as pioneer settlers underpopulated sparse colonies. assume formation viable requires interaction highly “pioneers” certain less competitive followers. withdrawal latter results general reproductive failure Thus, pattern turns natural selection towards maintenance variety individual programs competition.