Acknowledgements

This work was carried out in the Department of Biology of University of Oulu. I thank Professor Markku Orell for pleasant working conditions and especially the emeritus Professor Seppo Sulkava, a pioneer in the research of birds of preys in Finland, who lead me into the fascinating world of birds of prey through the analysis of prey remains, which many consider unpleasant tasks. However, studying food remains of the goshawk is like going bird watching excursion in the wings of a hawk. Talks with Seppo and another senior "man of bird of prey", field naturalist Kauko Huhtala were unforgettable. I am happy to have for supervisors such top ecologists as Erkki Korpimäki and Mikko Mönkkönen. By encouraging, advising, and above all through his incredible production of high quality papers on the ecology of birds of prey, has Erkki provided an impressive model of how to study in the difficult and labourous field of raptors and owls. Mikko"s support in statistics, working up with manuscripts and planning the work was irreplaceable. Though younger than the defendent, Mikko"s experience and versatility in the field of ecology is amazing. Alfred Colpaert, expert in GIS, made possible the analysis of habitat use of the hawks, and Maarit Pahkala helped analyse the museum data.

Several amateur and professional ornithologists helped me in the field work. Pentti and Markku Hukkanen, father and son, men devoted to birds of prey, searched many new nesting sites of goshawks to me. Seppo Haapala "nursed" the nests on the Isle of Hailuoto, Kari Koivula and Seppo Rytkönen gave hints of the hawks living in "tit area, Wytham wood of Oulu". The Zoo of the Department of Biology lead by Jari Ylönen gave important technical assistance in catching the hawks and Henry Sormunen the same in the field. Samuli Heikkinen liberated me several times from pinches I got stuck in with my computer.

The staff of the Zoological museum with former head Eino Erkinaro and present one Juhani Itämies showed patience during the field work when I successfully skipped the routine museum works. Especially this concerns my collegues Eero Lindgren and Pasi Paaso, who had to do the ‘dirty work’, handling dead animals in the museum when I enjoyed of pleasant field trips in beautiful mornings. No wonder if they sometimes had been envious.

I thank the Finnish Game and Fisheries Research Institute and there especially Marcus Wikman for providing census data of game animals. I also thank the Finnish Game Management Foundation, Jenny and Antti Wihuri Foundation and the Faculty of Sciences of the University of Oulu for financial support.

Finally I thank my wife, Tuija, and our five children, Tiia, Riku, Sini, Juho and Ossi, who brought joy to my life and resisted only little my continuous field trips also during the weekends.

Oulu, May 2000                                                                         Risto Tornberg