Snow Goose

 

 Snow Goose have skyrocketed in numbers and are now among the most abundant waterfowl on the continent. They have a white and blue morph as shown here.

The dark color of the blue morph Snow Goose is controlled by a single gene, with dark being partially dominant over white. If a pure dark goose mates with a white goose, the offspring will all be dark (possibly with white bellies). If two white geese mate, they have only white offspring. If two dark geese mate, they will have mostly dark offspring, but might have a few white ones too. Cornell All About Birds