Polymorphic variability in clutch size and laying date of the velvet scoter, Melanitta fusca (L,)

Koskimies, J. (1957). Polymorphic variability in clutch size and laying date of the velvet scoter, Melanitta fusca (L,). Ornis Fennica, 34(4), 118–128. https://ornisfennica.journal.fi/article/view/132613