Make a Japanese rolled omelet (dashimaki tamago), let it cool, and slice it. (Store-bought is fine, too.)

Shape the rice into small oval mounds, gently pressing to flatten the tops, and place a slice of egg on each.

Wrap a thin strip of nori around each piece.

Cut nori into small pieces for the eyes and feet, and attach them with a dab of mayonnaise as glue.

Use a round straw to cut out a small piece of carrot for the beak, and gently press it into shape.