Before you ever register color, your eye picks up shape. That's exactly why bird identification by shape is worth training on purpose. A few shape categories worth knowing: Robin-shaped. Upright posture, medium body, moderate tail. Sparrow-shaped. Compact, round-ish body, short conical bill. Warbler-shaped. Small and slim, thin bill, quick and active. Hawk-shaped. Broad wings, hooked bill, a silhouette you can read at a distance. Once a shape becomes familiar, you'll find yourself down to a handful of possibilities before you've even focused your binoculars. Do you have a shape you've gotten really confident recognizing?