Billions of birds undertake extraordinary migrations annually, facing a gauntlet of hazards created by human activity. Understanding and reducing these threats is essential for migratory bird welfare.
Migratory birds experience welfare harms that are almost entirely caused by human infrastructure and activity. Building collisions cause immediate death or severe injury. Light pollution causes birds to circle illuminated structures until exhaustion or collision. Habitat loss at stopover sites means birds arrive at resting areas to find their food sources gone - a welfare crisis equivalent to finding a motorway service station closed on a long journey. The cumulative mortality from human hazards is enormous - billions of birds annually. Migratory bird welfare requires action at multiple scales: individual buildings making windows bird-safe, cities implementing lights-out programs, and governments protecting stopover habitats.