Climate change is disrupting the timing and routes of migratory bird species, creating welfare impacts from mismatches between migration timing and food availability at breeding and stopover sites.
Climate change creates welfare harms for migratory birds that are diffuse, distributed, and often invisible: individual birds that arrive too late to access peak food resources for chick provisioning, experience extended flights across degraded stopover habitat, or encounter extreme weather at vulnerable points in migration. Each of these events represents an individual welfare impact — starvation, exhaustion, thermal stress — multiplied across millions of migratory individuals annually. The population-level declines that result from accumulated individual welfare harms represent an ongoing, escalating welfare crisis that will worsen with each additional degree of warming. The welfare case for climate action is not abstract — it translates directly into the experiences of billions of individual migratory animals each year.