Abstract from BTO Research Report No 330:

Banks, A.N., Coombes, R.H. & Crick, H.Q.P.

The Peregrine Falcon breeding population of the UK & Isle of Man in 2002 ISBN: 1-904870-57-0

Executive summary

1. Historical, current and prospective breeding territories of the Peregrine falcon (Falco peregrinus) in the United Kingdom and Isle of Man were surveyed during the breeding season of 2002 by volunteer and professional fieldworkers.

2. Field observations aimed to assess territory occupation at the beginning of the season, to record pairs that might desert after an early failure. Estimates of occupancy of unvisited territories were based on occupancy rates from visited sites in the same region.

3. Peregrines occupied 1,415 of 1,899 visited territories in the UK; an additional 77 unvisited territories were estimated also to contain birds, giving a grand total of 1,492 occupied territories of 2,032 known breeding sites. 420 new territories were documented, including notable expansion in inland England and South Wales. National occupancy of visited territories by non-breeders was between 20% and 27%.

4. The number of breeding pairs increased from 1,283 in 1991 to 1,402, an increase of 9%. The population now stands at 160% of levels estimated in the 1930s.

5. Although most regions experienced increased territory colonisation and rising breeding density, many traditional strongholds in North Scotland became deserted, whilst parts of mid-Scotland also underwent substantial declines in territory occupancy. Additionally, there were signs of a new decline in the numbers of Peregrines in North Wales, whilst Northern Ireland populations also showed a slight decline. However, most areas of England, Southern Scotland, South Wales and the Isle of Man saw increases in Peregrine occupancy.

6. The majority of new territories were either on natural cliffs or in quarries. Other human artefacts, including power stations and pylons, were also used for nesting. There were few new ground or tree nests.

7. The continuing wave of decline from Northwest Scotland through Argyll and central regions of Scotland is of concern, as are the newly detected declines in North Wales and Northern Ireland; research is necessary to ascertain why these traditional breeding grounds are becoming depopulated.

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