Birds with abnormal plumage colours that are caused by genetic mutations such as leucism, albinism and melanism, are considered very rare in wild birds. One published study suggested that only one in every 30 000 birds suffers from these abnormalities! Another even rarer plumage mutation is known as a ‘fawn’ or non-eumelanic mutation. This is illustrated in the following set of adult Greater Honeyguide photos taken in October 2014 at Mtunzini, KwaZulu-Natal, South Africa.
Feature image: The pinkish mandible and white cheek on the fawn Greater Honeyguide on the left shows that it is an adult (juveniles have dark blackish bills). The bird on the right depicts a normal plumaged male Greater Honeyguide (December).
These extremely uncommon fawn colour forms occur when the mutation causes a loss of black or grey pigments. This gives rise to birds appearing in various shades of fawn or brown.
