Since the ban on the majority of the persistent organochlorine pesticides over most of Europe, their effects on peregrines have diminished significantly, although populations of peregrines in other European countries are still at low levels.
Around 20% of the European peregrine population breeds in the UK and we therefore have an international responsibility to conserve this species.
The largest continuing threat to peregrines in the UK is from illegal persecution, particularly on grouse moors. Recent estimates by the Scottish Raptor Study Groups indicate that around a quarter of peregrine nests in southern and eastern parts of Scotland are subject to interference and killing.
The current population decline in northern Scotland may be the result of a reduction in prey availability caused by land use changes, or possibly the result of marine pollutants, including PCBs and mercury, present in the seabirds that form the diet of some peregrines in these areas.
As peregrine numbers have recovered, some pigeon fanciers and game interests have called for the removal of the legal protection given to peregrines. Maintenance of legal protection is required under European Birds Directive.
The RSPB believes that the highest level of protection is essential to the conservation of the peregrine, which remains comparatively rare, and is extremely vulnerable to human activities (including continued illegal persecution). Once the peregrine population declines, it takes many years to recover. The peregrine is a valuable indicator species of the health of the environment, but only if its numbers are not kept artificially low.
The peregrine is a widespread species, present at low densities. Because of this, targeted conservation action can be difficult. Broad scale habitat protection and reduction of pollution and chemical contaminants will benefit peregrines.
The RSPB and other organisations have been providing nesting ledges and boxes to help peregrines re-colonise their former ranges in the south and east of England. Continuing vigilance is needed to keep in check the illegal killing of peregrines by gamekeepers and pigeon fanciers, and the robbing of nests for eggs and chicks by egg collectors and falconers. The peregrine is included on the Green List of UK birds of conservation concern.