The cause is usually genetic but may also be related to the animal's diet. A Cornell University survey of unusual-looking birds visiting feeders reported that 4% of such birds were described as xanthochromistic (compared with 76% albinistic).
A Cornell University survey on birds at feeders found that 4% were described as xanthochromistic, while 76% were albino. The cause is usually genetic but can also be related to the animal's diet.