Song canaries compete at special shows. The birds compete on points awarded against various components , called ‘tours’ of their song. To hear some of these, this website allows you to hear them: http://www.germanroller.com/roller_canary_jukebox.html
One feature of the song varieties is that they are quick studies. It is important that the different breeds are not kept in earshot of each other, as they will imitate each others songs. As part of their training, they are placed where they can hear good examples of the breed type song from either a champion or (especially these days) a recording of one. The young birds hear these when they leave the nest and the song they hear becomes a model for their own.
The original wild canary had four different pigments in its feathers. Three different forms of melanin (eumelanin black, eumelanin brown, and phaomelanin) contributed to various black and brown shades in the plumage. In addition, a yellow lipochrome pigment, containing carotenoids derived from the diet, was present in each feather.
In the development of the various breeds, variations in the distribution, presence, and concentration of each of these pigments causes the differences in the colour and markings of each bird. A lot of genetic understanding is required by breeders of exhibition birds, as the genes containing each of these traits may be dominant, co-dominant, or recessive. They may also sometimes be sex-linked, which means that the genes concerned appear on the chromosomes controlling gender. In birds, the male has an identical pair of Z chromosomes, whereas the females have a Z and a W chromosome. This means that a recessive gene on the Z chromosome will appear in all females, but the trait will only be manifest in a male if it is inherited from both parents.
The wild canary is a yellow-ground bird, but white canarys exist. These lack the ability to express the lipochrome pigment, giving a bird which is variously light brown, grey, bluish, or pure white depending on what melanins are expressed.
The other feature of canaries is that in the course of domestication two distinct forms of body feather became established in all breeds. One type is called variously ‘buff’, ‘frosted’ or ‘non-intensive’. Birds carrying this body feather type appear larger and rounder, but also paler, than birds with the other type of feather (called ‘yellow’, ‘non-frosted’, or ‘non-intensive’), which is narrower, with no white edge, and has a higher pigment concentration. Similar variation exists in other domesticated cage birds, and I presume similar variation also exists in wild birds, at least the finches.
All this was the state of play up to the 20th century. At this point, experimenters began trying to see if they could expand the palette of colours possible in the canary. The chosen additional colour was red, and how red canaries became possible is the subject of my next post.