The effects of forestry on hen harriers Circus cyaneus

• Main Author: Madders, Michael
• Format: Thesis
• Language: English
• Published: 1997
• Subjects: GE Environmental Sciences; QH Natural history; QL Zoology; Circus cyaneus
• Online Access: http://theses.gla.ac.uk/71759/; https://theses.gla.ac.uk/71759/1/10391400.pdf; https://eleanor.lib.gla.ac.uk/record=b1680434

Changes in the Scottish hen harrier population over the past 50 years appear to be associated with the development of coniferous afforestation. Increases or range extensions have occurred in some areas with recently established first rotation forests, where harriers are believed to have benefited from the increased cover and prey resources that result from fencing. Conversely, population declines have been reported in areas where maturing trees have reduced the availability of open and semi-open ground for nesting and hunting. Clear-felled plantations restocked with trees could potentially provide suitable habitat for a further period, although current evidence suggests that harriers make only sporadic use of second rotation forests for nesting. The extent to which harriers utilise first and second rotation forests for hunting has not previously been quantified, yet this knowledge is vital if we are to manage harrier populations effectively. This study examines time budget information from watches of breeding harriers which had access to various types of forest and moorland habitat. The relative use made of each habitat was determined, and preferences related to measures of vegetation cover and structure and estimates of prey abundance. Site occupancy and breeding success were related to the availability of the habitats studied. The study was undertaken in Argyll, west Scotland. Habitat selection by foraging harriers was investigated at 2 scales, the first reflecting the process by which a harrier came to be in a particular habitat, the second identifying specific components within habitats that were selected. (Abstract shortened by ProQuest.).