The grey heron is a familiar sight on UK waterways, standing motionless for hours while hunting fish. Its welfare is affected by water quality, disturbance at colonies and fishing line entanglement.
Grey herons face welfare threats that are largely human-caused. Discarded fishing line entangles legs, bills and wings — causing slow starvation or drowning when birds are tethered to vegetation or submerged objects. Herons that ingest fishing hooks suffer from internal injury and inability to feed. Disturbance of heronries during the breeding season (January-June) causes chick and egg loss as adults abandon nests in panic. Water quality deterioration reduces fish stocks, forcing herons to travel further and exposing them to greater mortality risk. Nature reserves that maintain heronries with predator control and buffering from disturbance support stable colonies with high chick survival.