I found that feathers in the snow, close to the track of one or more birds that walked into the forest. Therefore I first thought of a bird like partridges but looking at the examples here I think it might be predators feathers (and the track was from other birds so).
My best guess is these are feathers of a goshawk. Compared to the examples from the sparrowhawk it looks closer to the sparrowhawk but as far as I know sparrowhawks does not life in Lapland during this time of the year? But I am no expert.
I don't have a ruler, so I hope you can work with this picture of the feathers.