Okay. Ever wonder why pigeons bob their heads? It’s so that they can perceive depth. Animals with front facing eyes like ours can tell how near/far something is based on the angle formed by our eyes (called stereopsis). Pigeons, being side-eyed, don’t have that option, so instead they compare the percieved size of things as they bob. Things that are closer will “grow” more than things that are far away.
Wait, does that imply “greater” dragons?