The northern gannet (Morus bassanus) nests in spectacular colonies on rocky Scottish outcrops including Bass Rock — the world's largest colony with over 150,000 birds. Plastic entanglement in nesting material has become a significant and documented welfare problem in recent decades.
Plastic entanglement causes slow, painful death through limb strangulation: as chicks grow within the nest, plastic loops around legs or wings tighten, causing ischaemia, tissue death, and eventually fracture or loss of limbs. Adults also become entangled during nest construction or when attending chicks. Death from entanglement is not rapid — affected birds may survive for weeks with progressive tissue damage. RSPB and voluntary conservation teams visit colonies to remove plastic and treat injured birds, but access constraints mean many birds cannot be reached. Prevention requires reducing marine plastic at source and engaging fishing industries in ghost gear retrieval.