Migratory birds face extreme physiological demands during long-distance journeys. Weather, habitat loss at stopover sites, and light pollution create welfare challenges for millions of individual birds each year.
Migrant bird welfare during migration involves both the extreme physiological demands of the journey and the acute hazards of urban environments. A bird arriving at a stopover site having crossed the Sahara in poor condition faces starvation if suitable food and shelter are unavailable. Building and window strikes cause traumatic death or injury. Light-disoriented birds grounded in urban areas are vulnerable to predation. The cumulative welfare costs of migration route hazards across billions of individual birds represents an enormous aggregate welfare burden that is largely invisible to most people. Reducing urban light pollution during migration windows is a direct and achievable intervention.