| Publication Type: | Journal Article |
| Year of Publication: | 1986 |
| Authors: | Dare, PJ |
| Journal: | Bird Study |
| Volume: | 33 |
| Issue: | 3 |
| Date Published: | 1986 |
| ISBN Number: | 0006-3657 |
| Keywords: | Corvidae, Corvus, Corvus corax |
| Abstract: | Breeding Ravens were censused, and some aspects of breeding performance monitored, during 1978?85 in two adjoining and contrasting upland regions. The Snowdonia mountains (926 km2) supported a large and dense population at a mean density of 9.5 km 2 per pair. Ac. 80% increase there since the 1950s is probably related more to increased food supply (sheep carrion) than to other factors: nest sites are plentiful. On the moors and enclosed sheep farms of Migneint-Hiraet hog (477 km2 ) Ravens bred at lower density (23.9 km 2 per pair), the population has remained stable since the 1950s, and numbers appear to be limited mainly by a scarcity of secure nest sites. Human persecution and disturbance of nests are unimportant in Snowdonia but are of greater significance in Migneint-Hiraethog. Nests were spaced regularly in both regions, indicating territoriality. Average breeding performance per pair was similar in the two areas. Future trends in numbers and breeding success, especially in Migneint- Hiraethog, are likely to be controlled mainly by food availabilty, which is strongly influenced by continuing changes in farming practices and in landuse.Breeding Ravens were censused, and some aspects of breeding performance monitored, during 1978?85 in two adjoining and contrasting upland regions. The Snowdonia mountains (926 km2) supported a large and dense population at a mean density of 9.5 km 2 per pair. Ac. 80% increase there since the 1950s is probably related more to increased food supply (sheep carrion) than to other factors: nest sites are plentiful. On the moors and enclosed sheep farms of Migneint-Hiraet hog (477 km2 ) Ravens bred at lower density (23.9 km 2 per pair), the population has remained stable since the 1950s, and numbers appear to be limited mainly by a scarcity of secure nest sites. Human persecution and disturbance of nests are unimportant in Snowdonia but are of greater significance in Migneint-Hiraethog. Nests were spaced regularly in both regions, indicating territoriality. Average breeding performance per pair was similar in the two areas. Future trends in numbers and breeding success, especially in Migneint- Hiraethog, are likely to be controlled mainly by food availabilty, which is strongly influenced by continuing changes in farming practices and in landuse. |
| URL: | http://www.tandfonline.com/doi/abs/10.1080/00063658609476918 |
| Short Title: | Bird Study |
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