Northern gannets, spectacular plunge-divers of UK and Irish coasts, collect monofilament fishing line and other debris to incorporate into nests, causing severe entanglement injuries to adults and chicks on breeding colonies.
Monofilament line is nearly invisible and cuts through flesh as birds struggle. Entangled gannets suffer progressive constriction, limb loss, inability to fly, and death by strangulation or starvation. Chicks in line-contaminated nests cannot fledge. The spectacular, densely-packed Bass Rock colony means that entanglement events are highly visible and the scale of welfare impact is documentable.