Fujimaki, Y., Miyazawa, Y. & Sasaoka, K. 1997: Intake of buds and catkins by captive hazel grouse Bonasa bonasia in winter. - Wildl. Biol. 3: 281.
The intake of buds and catkins of birch Betula platyphylla by captive hazel grouse Bonasa bonasia was measured from December 1987 to March 1988, in March 1991, from November 1991 to March 1992, and from November 1992 to March 1993. Buds included 15.3% crude protein, 32.9% crude fat, 14.1% crude fiber, and 4.1% sugar. The corresponding values for catkins were 14.1, 20.7, 22.6, and 5.8%, respectively. The amount of buds and catkins eaten by pairs of hazel grouse ranged from 8.3 ± 2.7 g/day in January to 11.8 ± 3.2 g/day (dry weight) in November. In single-bird trials, the amounts eaten ranged from 6.2 ± 1.7 g/day in November to 7.0 ± 1.5 g/day in January for males and from 5.7 ± 1.2 g/day in March to 6.6 ± 1.9 g/day in November for females. Mean gross energy values did not show significant seasonal and sexual variations, being 232.94 ± 102.92 kJ/day for pairs and 161.87 ± 41.23 kJ/day for single birds. The gross energy obtained by eating buds and catkins was lower than that obtained from artificial diets, around 340 kJ/day. This is probably because captive birds required less food than wild birds and were accustomed to an artificial diet.
Key words: Betula platyphylla, Bonasa bonasia, dietary composition, energy uptake, hazel grouse, Japan
Yuzo Fujimaki, Yukako Miyazawa & Kumiko Sasaoka, Laboratory of Wildlife Ecology, Obihiro University of Agriculture and Veterinary Medicine, Inada, Obihiro, 080 Japan