Figure 13.8 Cyclic fluctuations in gyrfalcons. From 1730 to 1770, falconry was popular in Denmark and the number of falcons captured and exported from Iceland showed regular cycles that occurred approximately every 10 years. After 1770, the popularity of falconry declined and the low demand for falcons could be met even in low-population years.

Data from Ó. K. Nielsen and G. Pétursson, Population fluctuations of gyrfalcon and rock ptarmigan: Analysis of export figures from Iceland, Wildlife Biology 1 (1995): 65–71.