If you look at this side-on view of these ducklings, you will see the fluffy texture, especially compared to the smooth poppies above. The ducklings have been worked in Ghiordes knots, a stitch also known as Turkey Work, in which a loop is made followed by an anchoring back stitch. These are worked closely across the area, and the loops cut open when finished. They can be trimmed or left as they are
This close up of the poppies shows their smooth texture alongside the butterfly, which has both smooth satin stitch for the wings and Ghiordes knots for the body.
This embroidery was worked from an English book called Countryside Embroidery Book by Lalla Ward, now unfortunately out of print but sometimes available in public libraries.
Experiment with different stitches yourself - have fun!