Plastic marine debris entangles, poisons, and starves seabirds worldwide. Understanding the scale and mechanisms of this threat informs both individual action and policy advocacy.
Marine plastic causes diverse and severe welfare outcomes in seabirds. Entangled birds drown or die slowly of starvation when mobility is impaired. Ingested plastic causes impaction and obstruction of the digestive system, reducing food intake and causing malnutrition in animals that may appear to be feeding normally. Chicks fed plastic by parents experience worst outcomes: their small stomachs fill with plastic that provides no nutrition, causing starvation despite apparently adequate feeding behavior. The welfare suffering of affected individuals is significant and the scale - hundreds of thousands to millions of birds annually - makes this one of the largest ongoing anthropogenic welfare crises for wild animals.