Stitched on 18-count Aida, the design will just fit into one of the standard 30mm diameter acrylic keyrings that are available from various craft outlets. For a sort of Barn-Owl effect, I used three shades of brown DMC perle cotton: I'm not sure that using this with 18 count is what you're supposed to do, but it works for me.

This one really does work up quickly, the only problem being the eyelet stitches, which get a bit crowded. I found it easiest to cheat and work the needle up through the centre hole, but that's probably because I'm being obtuse.

For a bit of variety, I did a baby owl. You can stick it on a branch next to the big one or, with a little ingenuity, have it nestle under mum's wing. I don't think it can be done any smaller (challenge).

I've found that the easiest way to mount these things is to discard the backing provided with the keyring and instead stick 50mm masking tape to the back of the finished design. Then, draw round the outside of the circular acrylic "lid" with a soft pencil and trim to the inside of the line. Once the design is in the keyring, add a neat piece of cotton backing and no-one will know the difference.