Capercaillie (Tetrao urogallus) Science Article 7
The diet of the Cantabrian Capercaillie Tetrao urogallus cantabricus was examined by fecal analysis. Droppings were sampled from April 1998 to May 1999 around 23 leks that were grouped in five zones. Winter diet consisted of beech buds, pine needles, buds and catkins of birch and holly leaves. In each zone, the birds fed almost exclusively on one of these species, so winter diet depended on local availability. During spring the consumption of beech buds increased in all sites, and later in the season a high diversity of herbaceous plants was included in the diet. The most important food during summer and autumn was bilberry. Considering the resources that were used as monodiet, beech buds showed both the lowest caloric content and highest the fiber content. The energetic problems derived from winter and spring consumption of beech buds are discussed, and we propose that under certain ecological condition this monodiet might be a limiting factor.
Rodriguez, A. E. & Obeso, J. R., Ardeola 47(1), 2000, 77-83