Peregrine populations - past and present
The British population of Peregrines nosedived dramatically in the 1950's, levelling off in the nick of time in the 1970's. This is a trajectory that anyone who has watched hunting Peregrines will be familiar with! Organochlorine pesticides such as DDT were shown to be a major problem, causing increased adult mortality, eggshell thinning and reduced breeding performance. By the early 1960’s, 80% of the UK population had been lost and the Scottish population had fallen to around 360 pairs.
DDT was banned throughout the EC in 1981 and Peregrine numbers recovered, reaching pre-decline levels in many areas by the late 1990's. The most recent UK survey in 2002 showed that increases had continued in Britain as a whole but that the Scottish population had decreased by 8% since 1991. Regional differences in population trends were suggested across Scotland, particularly in parts of the central, north and west Highlands.
Our work on Peregrines in Scotland
In collaboration with the other partners to the Scottish Raptor Monitoring Scheme (SNH, Scottish Raptor Study Groups, RSPB, SOC, JNCC and RBBP) BTO Scotland has been investigating Peregrine status and population changes in more detail and looking at possible reasons for the changes in different parts (Natural Heritage Zones) of Scotland
- Between 1991 and 2002, Peregrines numbers decreased in ten Natural Heritage Zones of Scotland, were stable in two and increased in nine of these Zones.
- The largest increase occurred in the Eastern Lowlands (increase of 30+ pairs) with increases in most other regions being minor.
- The largest declines in numbers occurred in the Northern Highlands, Cairngorms Massif, the Peatlands of Caithness and Sutherland, the North East Glens and Argyll West and Islands
- Productivity information available from the 2002 survey suggested that the number of fledglings per pair was also lower in the north and west of Scotland than in other areas.
- The recently completed BTO/BirdWatch Ireland/SOC Bird Atlas 2007-11 indicates that Peregrine declines in the north and west of Scotland appear to have continued since the 2002 national survey, to the extent that the species is now recorded as being absent from many 10km squares in which it previously occurred.
Peregrine survey - Scotland
UK Peregrine surveys started in 1961, and since this time have been carried out once per decade. The 2014 survey will be the sixth of its kind.
The 2014 Peregrine survey method will allow the findings to be compared and integrated between different areas, and even more accurate assessments of trends to be produced in the ~2024 survey, and thereafter. This will ultimately enable more effective monitoring of Peregrine populations, and will allow conservation priorities for this species to be based on reliable information.
The organisation of the 2014 Peregrine survey in Scotland will rely heavily on effective teamwork largely carried out by regional Raptor Study Groups, but with vital input from BTO Regional Representatives and other skilled volunteers.
In areas where volunteers cannot cover all the survey areas, their survey effort will be supplemented by professional fieldworkers. In an area such as Highland region, where surveys are planned for between 125 and 250 squares (ideally with three visits to each square), such cooperation will be essential if we are to achieve the desired level of survey coverage.