Which stamp is a non-postal item that cannot be used for postage?

The Bird Stamp is often produced as a part of a collectible series or for special purposes, and is not typically designed for actual use in postage. Non-postal items can include stamps that are created for display, educational purposes, or as a form of art, rather than for mailing letters or packages. In this context, while commemorative stamps and forever stamps are specially designed for postage and can be used to send mail, the Bird Stamp does not serve that functional purpose and exists primarily as a collectible item. A postcard stamp is specifically intended for mailing postcards, further distinguishing it from the Bird Stamp as a non-postal item.