Any fingering/sport weight yarn which produces gauge will work well. I used perle cotton (about 18 wpi) in a stable gauge which does not sag or distort over time.
Wintery birds mitten pattern with the thumb gusset. The mittens are knitted using just two colors at a time, the birds chests are embroidered with duplicate stitch afterwards.
Ravelry: Project Gallery for Røverkofta n pattern by Kristin Wiola