Paul F. Haworth

The association of grouse moor in Scotland with the illegal use of poisons to control predators

In the UK uplands, there is a conflict between the maintenance of high densities of red grouse (Lagopus lagopus scoticus) for sporting shoots and the conservation of birds of prey on grouse moors where shoots take place. Several authors have indicated that as a result of this conflict, illegal use of poisoned baits to control predators is more likely to occur on grouse moors, but this association has not been examined formally. Mapping a form of land management unique to grouse moors (‘strip muirburn’), we use a GIS analysis to show that records of illegal poison use from 1981 to 2000 were disproportionately associated with grouse moors in Scotland. The association between poisoning incidents in the uplands and grouse moors was stronger in later years of the study period. It is suggested that this was at least partly due to a decline in the illegal use of poisons away from grouse moors. There was no evidence of any temporal decline in poisoning incidents on grouse moors over the study period. This research indicates that illegal methods for controlling predators (including protected birds of prey) are associated with traditional field sports and points to the need for management action.

Re-introduction of the golden eagle into the Republic of Ireland

The golden eagle (Aquila chrysaetos) became extinct in the Republic of Ireland in about 1912. Historical evidence suggests that, in the early nineteenth century, the population exceeded 50 pairs. It is thought that the extinction was a consequence of persecution and habitat change. Because there seems little chance of natural recolonisation a re-introduction programme has been developed. It is intended to release up to 15 birds per year for 5 years, starting in 2001. Single chicks will be obtained from Scottish nests with twins. The ways in which this project adheres to the six main IUCN re-introduction criteria are addressed. Two simulation models are described. The first, GEPM, demonstrates that the removal of chicks from Scottish nests should not have a detrimental effect on the Scottish population. The second model predicts the probable home range occupancy if only 12 birds are released each year. It is expected that between 3 and 13 ranges will be occupied by 2007. The imprecision in this estimate is a consequence of uncertainty about juvenile survival rates. The rationale behind our reintroduction scheme is outlined to stimulate debate about the development of good practice.

Ranging distance of resident Golden Eagles Aquila chrysaetos in western Scotland according to season and breeding status

Capsule Home-range of resident pairs of Golden Eagle was usually smaller during a successful breeding season than during winter and during an unsuccessful breeding season. Aims To examine how Golden Eagles use space around their nests with respect to season and breeding status, and to compare home-range-use between a high and a low density region. Methods Nine adults in six mainland Argyll ranges were radiotracked between 1991 and 1996. On the island of Mull visual observations of range-use were obtained for five ranges between 1994 and 1998. Results Overall, Mull ranges were smaller than the Argyll ranges, reflecting the much higher range density on Mull. In both regions there were significant differences between ranging distances with season and breeding status. In general, ranging distances were smallest during breeding seasons when young were fledged. Conclusions Studies of range-use in Golden Eagles must be conducted across a 12-month period, as a minimum.

Conservation and management implications of habitat selection in the merlin Falco columbarius L. in the South Pennines, UK

Abstract A large area of moorland in the Pennines of northern England was systematically surveyed for breeding merlins Falco columbarius L. each year from 1982 to 1985. A detailed data base incorporating topography, vegetation, recreational and gamekeeping intensity was established. Relationships between the occurrence of breeding merlins and a wide range of environmental factors were investigated using discriminant analysis. Important habitat requirements of F. columbarius are defined and implications in terms of conservation and land management discussed. The predictive capacity generated by this study is outlined in terms of the possible effects of changing land use and land management upon the nature conservation interest. The results of the study are used to formulate conservation-based management proposals for the study area.

Hen harrier Circus cyaneus nest sites on the Isle of Mull are associated with habitat mosaics and constrained by topography

ABSTRACT Capsule: Hen Harriers Circus cyaneus on the Isle of Mull, UK, are associated with habitat mosaics consisting of moorland, scrub and forestry but avoid grazed land, suggesting that forested habitats could be managed sympathetically for the Hen Harrier in the future should the current UK population increase. Aims: To use distribution modelling to investigate nesting habitat associations using a long-term data set for the Hen Harrier on Mull. Methods: We develop area-interaction models using a least absolute shrinkage and selection operator penalty to explore the distribution of 102 Hen Harrier nest sites in relation to habitat and topography. Our model is then successfully validated in tests using data for 70 nest sites from subsequent years. Results: Our model is effective in predicting suitable areas for Hen Harrier nest sites and indicates that Hen Harriers on Mull are found in habitat mosaics below 200 m above sea level. Hen Harrier nest intensity is positively associated with increasing proportions of moorland and scrub, open canopy forestry and closed canopy forestry. Nest intensity is negatively associated with increasing proportions of grazed land. Conclusion: Hen Harriers avoid grazed areas but are relatively tolerant of other habitat combinations. These findings are supported by previous observations of Hen Harrier habitat use and have implications for the recovery of some Hen Harrier populations in Special Protection Areas and future forest management. Open canopy forest and forest mosaics could potentially be incorporated into landscape-scale conservation plans for Hen Harriers using the population on Mull as an example.