The Pearl mutation was first bred in West Germany in 1967 and was the
third mutation to appear in the Cockatiel. Pearl is a sex linked
mutation and can be combined with many other mutations.
Individual feathers over all or most of the bird are affected by a
lack of colour in a uniform pattern. Very much different to the lack of
colour that characterises Pied. Pearl markings causes the feathers to
look scalloped.
In the nest, Pearls cannot be identified until the chick is at pin
feather stage. These pin feathers will look either striped or dotted
before the feathers break out of the casing. The eye colour is the same
for whatever the pearl is put with. For example, a normal Pearl will
have dark eyes, a Cinnamon Pearl will have ruby eyes and a Lutino Pearl
will have red eyes.
Both sexes can display equal amounts of pearls as juveniles. As cocks
mature, they usually lose their pearling and will revert back to look
like a normal cock bird (depending on what colour it is, i.e. Cinnamon,
Pastel Silver etc.).