The marsh harrier recovered from near-extinction in the UK following pesticide bans and wetland protection, demonstrating how policy change can transform wildlife welfare.
Individual marsh harriers suffered acutely during the pesticide crisis: thin eggshells caused by DDT prevented successful hatching, and adults accumulated lethal organochlorine concentrations through bioaccumulation in prey species. Recovery shows that policy intervention addressing root causes of welfare harm can transform population-level outcomes. Persecuted individuals at game estates are killed or injured through illegal trapping and shooting. Wetland drainage reduces prey availability, forcing longer and more energy-intensive foraging. Continued wetland creation and restoration provides the direct welfare benefit of adequate habitat for successful breeding.