I like this photograph from both a nerd (techie) perspective and the image itself.
The bird on the left is a juvenile, just about ready to fledge and leave the nest tree. The feathers are short, the face has no distinguishing features, and the legs still a little lighter in color.
On the right is the adult. Darker legs, fading colors around the eyes, and longer flowing feathers make the age difference clear when they are side by side.
We are privledged to be able to see, and photograph wildlife like this.