Status of the Hen HarrierCircus cyaneusin Scotland in 1988–89

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Abstract
A sample survey of Hen Harriers in 1988–89 was based on 10-km squares according to their category of proof of breeding in 1968–72. From this sample the Scottish population was estimated at 570±150 pairs with 95% confidence. Seventy-one pairs were found on Orkney and 389 proved or probable pairs and a further 139 possibles were located elsewhere. About 60 pairs nested in England and Wales. An expansion of range since 1968–72 is mapped. Numbers have fallen on some grouse moor study areas. Nesting success on grouse moors was only 14% compared with 40% on other heather moors and 66% in young conifer plantations. Many of these failures on grouse moors were due to human persecution and by conservative estimates, 30–80 breeding adult birds were illegally killed each summer.