In this case, three different gauges. The main piece (the copper one here) is 12 gauge, about 10 inches long. The longest end (the outer wing finger) is 4 inches long, finger joint to "elbow" is 3 inches, "elbow" to "shoulder" is 2 inches. The rest (about half an inch worth) is curved around to make a "base" for the shoulder joint. If you plan on the curve always pointing "out" from the body, this will give you a good reminder to not make both wings exactly the same!

The piece that will be the inner wing fingers is 18 gauge, 6¼ inches long. The longer of the two fingers is 3½ inches long, what is left will be the shorter finger.