"Cuttlebone" is bone from a marine fish, so it is primarily calcium carbonate. Cage birds such as parakeets need a calcium source especially if they are laying eggs. Also look for cage bird "mineral blocks" which are probably calcium from terrestrial mine sources, not fish. Either way, the birds gnaw on it, but the cham's wouldn't, so you'd have to grind it up into a fine powder (I've done it...used a file, hammer and chisel, or a Dremel grinding wheel). The one concern with overusing a marine fish bone might be mercury contamination...just how much of a worry would depend on where the fish was caught, and I doubt you can get that info from any source. In a pinch I doubt it would be a problem, but I would look for a "terrestrial" calcium product for the long haul.