Vol. 33 (2023)
Volume 33 comprises the continuous publishing of open access contributions in Ornis Svecica. The cover (available under the Creative Commons Attribution 4.0 International License) features an adult male Long-tailed Duck Clangula hyemalis in a marine winter landscape, photographed by Frode Falkenberg © (falkefoto.no). This is the focal species of this year's first paper, in which Larsson (2023) presents a method to estimate age and sex ratios among wintering Long-tailed Ducks from photo surveys at sea.