I love the shapes crows make as they fly, but finding a way to recreate their inky silhouettes on clay has been a challenge. I think I'm finally coming up with a strategy that's fairly straightforward.
It starts with a set of custom rubber stamps that I ordered from Atlas Stamps (so much easier than the handmade option). After the pot is trimmed and dried, but before it's been bisque fired, I gently stamp the images onto the clay, curving the rubber stamp to match the shape of the fragile greenware.
Pretty much any kind of stamp pad with do. These two were given to me and my sisters sometime in elementary school, and somehow (amazingly) still have enough ink and moisture to be usable. I start with a light color, which gives me the option of redoing the stamp if I don't like the placement. The organic dyes in the stamp pad will all burn out in the firing, so I don't worry about any extra marks I've made on the clay.
I then use a very fine brush to paint black underglaze over the stamped outlines, using the original set of photos as a reference.
Once the underglaze is on, they're ready to be bisque fired. It also works to do this stamping and painting on bisqued ware, but the raw underglaze sometimes resists the glaze, leaving an uneven surface on the finished piece.