Common swifts undertake one of the most demanding migrations of any bird, with welfare challenges concentrated during the return journey to Africa in late summer.
Swift welfare during migration is determined by food availability along routes and the physical demands of continuous aerial life. Swifts cannot land safely on the ground and must maintain flight or cling to vertical surfaces. Poor insect availability along migration corridors forces birds to deviate from optimal routes, increasing journey length and energy expenditure. Juvenile swifts face particular welfare risks on their first migration without experience of optimal routes and stopover sites. Climate change reducing aerial insect populations is creating increasing welfare costs along migration corridors that cannot be addressed locally.