Other colour variants
30 March 2010
Leucistic or 'dilute' birds are abnormally pale
or washed out, although the normal pattern and colour of the
plumage is discernible. This plumage aberration is perhaps more
frequent than any except albinism, though still very unusual.
In erythristic birds chestnut-red replaces
other forms of melanin. The best known example probably being the
rare 'hepatic' phase of the female cuckoo.
Xanthochromism involves the loss of dark
pigment and abnormal retention of yellow pigment, and has been
recorded in wood warbler and yellow wagtail.
Some birds obtain their red or yellow colour from carotenoids in
their diet. Diet deficient in carotenoids can make the bird
gradually fade and become white. The flamingo is a good example of
Conversely, a bird that normally has no red pigment, may assume
an orange or crimson colour if fed on a diet high in eg yew berries