In layman's terms, a morph is a specific coloring of plumage in a species. So they aren't different sub species, they are the same species, they just have a different plumage and they have it throughout life. The best example I could give is like when a lab gives birth to pups and there are black, yellow, and chocolate colored pups. They don't change colors at any time but they are the same as their siblings. There are actually several different morphs for red-tails but in Oklahoma we most commonly see Krider's and Harlan's.
