Abstract
There are two schools of thought among canary breeders. Some claim that Ivory appeared as a result of mating White x Red-orange. Others instead claim, Ivory appeared spontaneously. We can disregard opinions and state, Ivory is a definite mutation.
Ivory factor appeared in Holland about 1950, but it was not until 1964 that Ivory factor became recognized.
Ivory color is very hard to define, because it is not a color of definite hue. The best definition that I can give of Ivory color when bred from yellow parents is (creamy-white) ~ a color very much like the color of the billiard ball, made from the tusks of elephants. When bred from Red-Factor parents, Ivory color will have a tinge of Red-Orange color and will be defined as Rose-Ivory. A British publication called "The New Canary" published by Canary Breeders Association, defines Rose-Ivory as "Rose Pastels".
Ivory factor can be introduced to melanin canaries, and it can be added to the three ground colors: yellow, red and white. A Green-Ivory canary is easily confused with Blue canary. The GreenIvory, when observed closely and compared to a Blue, will appear less diluted with creamy white characteristics.
A Bronze-Ivory will have a color somewhat bordering on Violet. I personally breed some of these above mentioned Ivory factory combinations. I found that Ivory factor has tendency to reduce the size of the canary.
Genetically, Ivory is a sex linked mutation, therefore easily introduced into other colors. For the sake of simplicity, we will use yellow canary as a normal, mated to Ivory in all of the possible combinations to show the genetic results.
Please refer to figure I.
XX represents male and XY represents female canary. Each chromosome is numbered to show inheritance from the parent. The Y chromosome in the female is the empty chromosome. The letter within the square represents GENOTYPE. A pair of chromosomes represents the bird, and the color of the bird's feathers (phenotype) is indicated below the squares. The top two pairs of squares represents the parents. The four pairs of squares below represent the offspring. The results of mating in Figure I are:
A) male Yellow X female Ivory: 50% males yellow/ivory - 50% female yellow.
B) male yellow/ivory X female yellow: 25% male yellow - 25% male yellow/ ivory - 25% female yellow - 25% female ivory.
C) male yeliow/ivory X female yellow: 25% male yellow/ivory - 25% male ivory - 25% female yellow - 25% female ivory.
D) male ivory X female ivory: 50% male ivory - 50% female ivory.
E) male ivory X female yellow: 50% male yellow/ivory - 50% female ivory.
Mating "B" not practical because we will not know which of the males is plain yellow or carrier of ivory. To find the carrier, we must test breed them in the next years matings,, thereby losing much time.