Aerial insectivores have shown large declines in abundance across Europa and North America, with agricultural intensification often identified as the main cause of decline. Using a long-term dataset of individually marked Tree swallows Tachycineta bicolor monitored over 13 years in southern Québec, we used multi-state CMR models to integrate and quantify the effects of local climatic variables, density of inter-specific nest competitors and agricultural intensification on the dynamics of this population.