I hand-stitched the bird on, but next time I think I would machine sew (as long as the leather wasn't too thick) as it's hard to get the stitches neat by hand. I used the reverse, suede-like side of the leather for this.
Once the bird was done, I thought a finishing touch with a bit more leather was in order. I chose a slightly thicker scrap from the bag and cut two strips to fold over the top edge, where the magnetic catch goes. Although these look like they're stitched on, they're glued. I stitched around the edges (by machine), then put the magnetic snap through the leather and through the complete thickness of the bag. Then I glued each tab down on the outside.
I highly recommend this pattern (and Noodlehead in general!). My fabric was thick cotton, with thick interfacing. The lining is quilting cotton.
Happy summer! x