Aspects of the ecology of black grouse (Tetrao tetrix) in plantation forests in Scotland

Aspects of the ecology of black grouse (Tetrao Iciri_x), a species of' international conservation concern, in commercial plantation forests were investigated between 1996 1998 at three study areas in Scotland. The aim was to identify the species' habitat and area requirements in first and second rotation forestry. The distribution of males was assessed using lck surveys and studied at two spatial scales in the mixed rotation forest landscape of Cowal. Argyll and at two spatial and temporal scales in highland Perthshire -a less afforested region. In addition, a radio-tracking study was undertaken to examine the habitat selection of broods in two first rotation plantations in north Perthshire. Pre-thicket forestry formed a preferred habitat but, in terms of lek distribution, black grouse did not differentiate between first and second rotation pre-thicket habitat patches. Patch size, the total amount of forestry in the area, the proportion that was pre-thicket stock and its level of fragmentation. however, were all correlated with the probability of a location holding a lek and the number of males attending it. Lek isolation reduced the number of males in attendance and increased the likelihood of the lek declining over time. Brood habitat preferences differed from those of adult birds. Broods selected habitats that were `open' enough to support a rich ground flora and presumably an adequate invertebrate fauna but also 'closed' enough to provide cover, representing a compromise between foraging potential and predation risk. Brood roost sites differed by having shorter trees but a higher degree of cover I-1.5 metres above the ground. Results from the different study areas and age classes are compared and contrasted and the implications of the research findings for `black grouse friendly' forestry management are discussed. Finally, suggestions for further work are made. Acknowledgements First. and foremost, I would like to thank my supervisors for their supervision and support during this research project; David Baines particularly in the field years and Peter Hudson in the writing up period. Ken Wilson revealed some of the mysteries of S-PLUS and Dan Tompkins, one of Peter's post-doctoral assistants, provided exceptionally useful advice on statistical analysis and was a valued sounding board. Thank you all. Thanks are due to the trustees of the Martin Wills Fund; their donation made this research project feasible. Thanks are also due to the Stirling University's Department of Biological and Molecular Sciences' Research Fund, Faculty of Natural Sciences' Development Fund and Access Fund, which also provided financial assistance. I am very grateful to all the landowners, agents and managers who allowed me access to their land. The Perthshire Black Grouse Study Group generously allowed me to use their lek survey data they have collected since 1990.1 would like to thank all the members of the group and the chairman, Martin Robinson, in particular. Whilst not formally connected to this project, the co-operation and assistance provided by the Forestry Commission and Forest Enterprise were invaluable, not least for providing accommodation in the 1996 field season. In particular, Dave Anderson, Alistair Clark and Hugh Gibb, the Forest Enterprise rangers in Cowal were extraordinarily tolerant of my dawn activities and provided a great deal of information about leks in the area. On one notable occasion Dave rescued the car from a quad-bike track thanks! Kenny Hay, Geoff Shaw, Ian Adams and John Spittal were also very helpful. Steve and Linda Petty's interest, empathy and hospitality helped to keep me this side of sanity. Too many foresters, stalkers and private individuals to mention provided assistance and cooperation. Thanks to all, but in particular: Colin Chisholm; Digby Guy; Life Braag; Winston Churchill; Paul Kent and Anton Lockett.