FAQ: is it possible that the “goldenface” budgerigar [Melopsittacus undulatus] is genetically identical with the bl1-bl2/bl1 Agapornis fischeri (*aqua* phenotypes) ?
That is possible. We know that there are blue 1 and blue2 in budgerigars, but they never considered the possibility of phenotypes created by crossing-over between blue1 and blue2. In order to be able to prove or disprove this theory, we need sufficient breeding reports. But the chance is real because there are phenotypically lots of similarities.