HUNTING METHODS AND CHOICE OF PREY OF GYRFALCONS FALCO RUSTICOLUS AT MVTN IN NORTHEAST ICELAND

• Published in: Ibis
• Main Author: Bengtson, Sven‐Axel
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 1971
• Subjects: Falco rusticolus; gyrfalcon; Iceland
• Online Access: http://dx.doi.org/10.1111/j.1474-919x.1971.tb05180.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1474-919X.1971.tb05180.x; https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1474-919X.1971.tb05180.x

SUMMARY Gyrfalcons breeding near Myvatn in northeast Iceland were studied from 1960 until 1970. Hunting methods and successful attacks are described. The Gyrfalcon usually hunts low over the ground and tries to surprise and flush its victim and then stoop upon it. If this fails, it may pursue. The choice of prey was studied by observations from mid‐May to September of Gyrfalcons carrying prey, and by examining food‐remains at eyries. Ducks and Ptarmigan comprised about 49% and 41 % respectively by number of individuals, and 62% and 35 % by estimated fresh weight. One pair utilised some 88 kg of food to raise foui young. The proportion of Ptarmigan in the diet increased during the study, reflecting the increase of the Ptarmigan population and suggesting that Ptarmigan are the preferred prey since waterfowl were abundant all the time.