Ospreys returned naturally to Scotland in 1954 after a century's absence and have been reintroduced to England and Wales. Their welfare depends on clean fish-rich lakes and freedom from human disturbance at nest sites.
Osprey welfare at nest sites is particularly sensitive to human disturbance. Adults disturbed by visitors approaching too close abandon nests temporarily — in cold weather this causes egg chilling. The RSPB Loch Garten nest has been watched by visitors since 1959 without welfare harm because viewing is from a purpose-built hide at appropriate distance. Illegal egg collecting — still documented at some Scottish sites — is both a criminal offence and a direct welfare impact on established pairs. The reintroduced Rutland Water and Poole Harbour populations demonstrate that restored populations with appropriate protection achieve breeding success comparable to long-established Scottish colonies.