Grey herons are legally protected in the UK but persecuted at fish farms and fishing venues, while their welfare is also affected by pollution and wetland loss.
Herons illegally shot at fish farms or angling venues experience acute injury and death, with wounded birds potentially dying slowly from injuries. Persistent organic pollutant accumulation through contaminated fish prey causes immune suppression and reproductive failure. Heronries disturbed by tree felling during breeding season cause nest collapse and chick mortality. Wetland drainage removes foraging habitat, increasing energy expenditure for feeding. Cold winter periods can cause nutritional stress when prey becomes difficult to access.