Publication Type: | Journal Article |
Year of Publication: | 1995 |
Authors: | Crick, HQP, Ratcliffe, DA |
Journal: | Bird Study |
Volume: | 42 |
Date Published: | 1995 |
ISBN Number: | 0006-3657 |
Keywords: | Falco, Falco peregrinus, Falconidae, Ireland, Rhynchodon, Rhynchodon peregrinus, United Kingdom |
Abstract: | A survey of Peregrines in the breeding season of 1991 gave an estimated total of 1283 pairs occupying known nesting territories in Britain and Northern Ireland. 1214 territories were found occupied, 53 by apparently single birds, and 141 known territories (9%) were not visited. Overall territory occupancy was 83%. The figure of 1283 pairs represents 147% of the overall population level believed to exist in 1930??39, and 167% of that counted during the previous national survey, in 1981. The net increase was geographically uneven, being greatest in a broad zone from the eastern Grampians to South Wales, whereas numbers were still well below pre-war level in coastal south-east England. In coastal and western inland areas of the northern Highlands, numbers have declined since 1981. Throughout the UK, many coastal populations have substantial proportions of territories occupied by nonbreeding birds. Population growth has involved both an increase in breeding density and expansion of breeding distribution, the latter especially through increased use of nest sites on small cliffs, quarries, buildings, rocky banks and even the ground. Both kinds of increase have been fuelled by a substantial increase in production and probably survival, reflecting the disappearance of pesticide problems, reduced persecution through protection efforts, and locally enhanced food supply through growth of pigeon racing. The failure of the northern coastal population to recover is attributed mainly to contamination by marine pollutants through the food chain, although this needs further research.A survey of Peregrines in the breeding season of 1991 gave an estimated total of 1283 pairs occupying known nesting territories in Britain and Northern Ireland. 1214 territories were found occupied, 53 by apparently single birds, and 141 known territories (9%) were not visited. Overall territory occupancy was 83%. The figure of 1283 pairs represents 147% of the overall population level believed to exist in 1930??39, and 167% of that counted during the previous national survey, in 1981. The net increase was geographically uneven, being greatest in a broad zone from the eastern Grampians to South Wales, whereas numbers were still well below pre-war level in coastal south-east England. In coastal and western inland areas of the northern Highlands, numbers have declined since 1981. Throughout the UK, many coastal populations have substantial proportions of territories occupied by nonbreeding birds. Population growth has involved both an increase in breeding density and expansion of breeding distribution, the latter especially through increased use of nest sites on small cliffs, quarries, buildings, rocky banks and even the ground. Both kinds of increase have been fuelled by a substantial increase in production and probably survival, reflecting the disappearance of pesticide problems, reduced persecution through protection efforts, and locally enhanced food supply through growth of pigeon racing. The failure of the northern coastal population to recover is attributed mainly to contamination by marine pollutants through the food chain, although this needs further research. |
URL: | http://www.tandfonline.com/doi/abs/10.1080/00063659509477143 |
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