Temperatures that fifty years ago were recorded at the beginning of April now occur at the beginning of March, and autumns and winters are increasingly warmer. These changes have generated alterations in the life cycle of plants and animals, with important asynchronies in the interactions between species, for example between plants and their pollinators or between plants and herbivores. Similarly, climate change and global warming are causing variations in the behaviour of some bird species and the place where they live. This is corroborated by a study recently published in the Journal of Animal Ecology, which belongs to the British Ecological Society. The study analyzes changes in bird communities in eight European countries, Canada and the United States between 1980 and 2016, with data from more than 1,200 species (about 3,000 million birds in total population). This information is possible thanks to the participation of volunteer ornithologists, which in the Mediterranean has been made possible thanks to the Catalan Institute of Ornithology within the Monitoring Plan for Common Birds in Catalonia (SOOC). This project aims to determine the trends of common bird species and, from the data obtained, to generate environmental indicators.