The UK's breeding population of curlews is of international importance, being estimated to represent more than 30 per cent of the west European population.
There have been worrying declines in the breeding population throughout much of the UK, with the Breeding Bird Survey indicating significant declines in Scotland, England and Wales, and an overall UK decline of 42 per cent between 1995 and 2008.
Earlier surveys recorded a 60 per cent decline in breeding numbers in Northern Ireland between 1987 and 1999.
Curlews are also declining more widely across their global breeding range and, consequently, their IUCN status is near threatened. The species is a UK BAP priority, and is Amber listed due to the international importance of both breeding and wintering populations in the UK, its unfavourable conservation status in Europe and the declines in UK breeding numbers.
Within the UK, curlews breed on a range of habitats but are primarily birds of extensively managed rough grasslands, moorlands and bogs. The bulk of the breeding population (around 60 per cent) occurs in Scotland, with the majority of the remaining birds in northern England.
Agricultural intensification of upland farmland and moorland (eg drainage and reseeding) is likely to have been important in causing past declines in breeding populations, as has afforestation of moorlands, and these activities may continue to exert deleterious effects on populations.
However, RSPB research in Northern Ireland identified high levels of predation on nests as the likely cause of population declines, with foxes being the most important predators. Similar findings have been obtained from declining populations elsewhere in Europe, suggesting that increases in predator populations have also contributed to declines.
In some upland areas, the control of foxes and crows by gamekeepers managing moorlands for red grouse shooting may be important in maintaining breeding curlew populations and preventing further declines.
We are currently undertaking research that seeks to establish the extent to which declines may be related to changes in moorland habitats and land managements, including gamekeeping and predator control.