Canaries and related birds have always held a fascination for me not only because of their color and appearance but because each species has its own uniquely pretty song. The breeder can learn to distinguish the species just by hearing an individual bird sing. Species include Siskins, Grosbeaks, Goldfinches, Greenfinches, Buntings, Chaffinches, Saffrons and Sparrows.
All of these species build a cupshaped nest except for the Saffron Finches and Sparrows which nest in cavities.
Canary hybrids have been reported from each one of these species at one time or another (see Canaries and Related Birds by Horst Bielfeld). None of the hybrids are prettier than any one of the pure species and neither is their song better than the songs of the domesticated Canaries or wild Linnets. Red Siskins have been used repeatedly in producing the red factor Canaries
but most certainly not for their song.
Most of the hybrids produced turn out to be infertile and are referred to as "mules". Only the Red Siskins (being closely related to the Canary) occasionally produce fertile cock birds. The hens from this cross are always infertile. Even hybrids from the Yellowhooded or European Siskin crossed with the Canary are sterile.
As the Red Siskins have been used to get a red factor Canary, so has the Indigo Bunting been used by some breeders in an attempt to get blue Canaries. But this has not worked as buntings are a more distantly related species although occasional reports appear of such hybrids being produced. Indeed, one report stated that the hybrids were able to reproduce among themselves and even with Canaries.
Now I, myself, have never heard of blue Canaries. Nor has anyone that I know. If such a hybrid has ever occurred, it most certainly would not be fertile. If I am wrong then where are
all the blue Canaries? Nowadays some gray Canaries are being referred to as "blue" but most certainly they are not Bunting hybrids.
One could, perhaps, argue either for or against hybridizing with Canaries. After all, most hybrids are sterile. How could this possibly affect the finch species' It can affect them. The problem begins when back crossing or hybridizing with various finch species occurs. In such cases a bird that was genetically only one-quarter hybrid could look like a pure species and be bred with other pure birds. Some of the species are very closely related and look very much alike. This means that some of the hybrids are capable of reproduction. We are all familiar with the Estrildidae finches including Redcheeked Cordon Bleu, Blue-capped Cordon Bleu, Blue-breasted Cordon Bleu or Ruddies and Strawberry Finches and certainly the Canary related large Green Singing Finch and the small Green Singing Finch to name just a few of the species.
111e Australian Federation of Aviculture is strongly opposed to crossbreeding and so are most breeders and dealers. I know for a fact that most breeders in Sydney would not buy or offer hybrids for sale.
Often breeders of Red Siskins form groups of three or four members and exchange young Siskins among themselves. In this way they retain the birds' purity.