Answers are grounded in this paper and cite their sources.
Svein Myrberget, Variations in the Production of the Willow Grouse Lagopus lagopus (L.) in Norway, 1963-1972, Ornis Scandinavica (Scandinavian Journal of Ornithology), Vol. 5, No. 2 (1974), pp. 163-172
No takes yet. Share an insight, caveat, or question.
Svein Myrberget (1974) studied this question.
Synapse has enriched 10 related papers. Consider them for comparative context: