Northern Cardinals are known for their red plumage, but some of these birds have yellow feathers instead.
The theory is that these unique yellow feathers are caused by a genetic mutation that results in the bird missing the enzyme that converts yellow pigments in their food to red, leading to yellow feathers.
This mutation only affects an estimated 1 in 1 million birds, so seeing a Yellow Northern Cardinal (not to be confused with a Yellow Cardinal) is truly a rare event!
