How to make a natural pen? What sort of ink to use?

Partly cloudy weather dispersed early afternoon, the sun was shining and the wind still rustled. The kids and I headed to the park to catch a few breaths of fresh air. Climbing on the exterior of the play structure (a part climbing was not intended for) I saw Moses braving a new adventure. He was his own Don Quixote. Later he brought me dirty, goo-ridden black and gray raven feather. "I am going to make a pen out of this, Mom." That idea sounded inventive to me. Then he pointed to a nest, the source of where the feather had likely fallen from. "How do they make their nests?" With out yet giving me opportunity to shower him with my 29 years of insightful knowledge about the topic of bird nests he continues, "Looks like sticks and leaves and probably small things that look cool in a nest. " I added a piece from a public broadcasting piece I had seen in the past about about urban birds snatching wire clothing hangers and using them in place of the usual fare. His face gave a "hmm." response. Then he asked me what ink was made of. He had what he deemed suitable for the pen-the quil but realized it wouldn't write. I was thinking. Another mother at the park offered her idea, "Beet juice." I thought that was a good idea. It reminded me of the natural colored play dough we made the other day. Beets are back in vogue. Moses surprised me as he always does. "I think ink comes from squids." The minutes before Moses is tucked into bed, Simon often gives Moses some facts on the animal he has been thinking about most that day. On more than one occasion it has required some outside research. Being witness to this discovery process I can't help but wonder if we allow our kids to be naturally curious what sort of adults might they turn into. It's a beautiful thought.