Although there are general patterns to Golden Eagle feathers, there are great variations in color, patterns of color, and distribution of color. Coloration is genetic, and the gene factors are multiple allelle genotypically, and in their effect.
The coloration can be anything from intense black (melanistic), to brown-black, to cinnamon brown. The white coloration merges from cream white to tans, yellow-browns to grays. Yes, and in freak circumstances, even a light shading of medium blue.
Some young eagles have demarcation between white and black almost like it was laid off with a ruler.
Sometimes the demarcation line is gracefully arched.
Sometimes the demarcation
line sort of dribbles or
becomes small peninsulas and bays.
There is a story that Plains Indians received some tails in trade from Bavarian Eagles from the Alps Mountains of Europe. These birds have a smaller area of black at the tip of the feather.
