Abstract:
Albinism has been recorded in many vertebrate taxa (Halls 2004). It
is a genetic anomaly in which an autosomal recessive gene causes an
absence of the enzyme tyrosinase, resulting in a total lack of melanin
pigment in the skin, scales, hairs, feathers and eyes (van Grouw
2006). The skin and eye colour of albinos is pink because the blood
can be seen through the transparent, unpigmented tissues. In birds, it
is the most frequently reported colour aberration, although it is the
least frequent in occurrence. This is because it is commonly mistaken
for the most frequently inheritable aberration in birds, leucism, which
is a partial or total lack of melanin in the plumage (sometimes also
in the skin)—but not in the eye—due to an inherited disorder of the
deposition of these pigments (van Grouw 2006). There are at least 10
other types of inheritable colour aberrations in birds.