Aviculture
The blue mutation was originally found in wild birds in the 1920s and is the oldest colour mutation known in the lovebird genus. The other mutations are a result of selective breeding in aviculture, such as two cobalts which will make a mauve (black). Various color mutations exist, including blue, cobalt, mauve, slate, dilute slate, violet, lutino (ino) and albino. The latter two are mutations where some color genes do not get passed on from the previous generation. In the case of the lutino the green color gene is not passed on. In the case of the albino, none of the color genes are passed on. The albino mutation is the latest color mutation.
White eye-rings lovebirds, of which black-masked is part of, are also more aggressive in comparison to the peach-faced lovebird.
Read more about this topic: Yellow-collared Lovebird