Actually, first year red tails have a striped tail. The red tail feathers are found on mature birds. There are several sub-species (i.e., races) of red tails in North America that differ mainly in how light or dark the breast and body are. For example the Alaska population is quite dark, while the prairie form is quite light. What struck me about this guy was the lightness of the breast and body feathers. Feather color also depends upon how recently the feather emerged after a molt. There is also leucitism, but let's not go there.