Eurasian hobby Falco subbuteo, perched in tree, Surrey

The historical decline of birds of prey

Bird of prey destruction increased dramatically during the 19th Century when game shooting became more widespread. As numbers declined, birds of prey were increasingly sought-after by egg and skin collectors.

Historical decline

By the end of the First World War, five of our 15 breeding birds of prey (goshawk, marsh harrier, honey buzzard, white-tailed eagle and osprey) had been driven to extinction in the UK.

Five more species (golden eagle, hobby, hen harrier, red kite and Montagu's harrier) all declined to fewer than 100 pairs at some stage between the 1870s and 1970s.

During the World Wars, gamekeeping declined as keepers went off to fight. Less destruction occurred, and some species like the sparrowhawk increased in numbers. However, killing by game managers increased again at the end of the wars, and peregrines were killed on government orders to protect carrier pigeons during the Second World War.

The introduction of myxomatosis in 1955 to control the rabbit population contributed to declines in buzzards, and many birds of prey were poisoned by organochlorine pesticides such as DDT, leading to widespread declines.

Organochlorines

Organochlorine pesticides were widely used in agriculture throughout the 1950s and '60s. These pesticides were able to persist in the environment for a long time and were soluble in fat, allowing them to accumulate up the food chain, concentrating in top predators such as birds of prey. This caused severe problems of eggshell thinning and increased adult and chick mortality.

Peregrines and sparrowhawks were particularly affected by organochlorines. Peregrines fell to 360 pairs in Britain by 1963, largely because of pesticide poisoning. A voluntary withdrawal of the pesticides began in 1962, with a total ban in place by 1982. This has played a large part in the recovery of some species.