[1]
Larsson, K. 2023. Age and sex ratios of wintering Long-tailed Ducks Clangula hyemalis can be determined by analysis of photos of flying flocks at sea: A method description. Ornis Svecica. 33, (Mar. 2023), 1–20. DOI:https://doi.org/10.34080/os.v33.23757.