The Pearl Society Finch
Translated with permission from "Onze Vogels", Sept. 2000, pg. 383, the bulletin of the Nederlandse Bond van Vogelliefhebbers.
We cannot be too overly pleased with the amount of color mutations in the Society Finch nowadays.
After decades of breeding with the almost classic mutations chestnut, red brown and white, only two mutations have been added in the eighties, namely the gray and the ino. These new mutations gave breeders of society finches a new boost. 
The fact that those mutations appeared in Belgium and Denmark resulted in other mutations that were enriching to the variety of the Society Finch. In the gray series the black gray, chestnut gray and red gray originated. In the ino mutation, breeders made the ino crème and the ino gray possible. Furthermore the dilute chestnut gray and dilute red gray appeared true gains that were real assets to the Society Finch population. Also breeding the clearwings, especially with the Red Gray Society Finch proved to be a real challenge. The number of Society Finch fanciers has increased significantly since the early 80's, especially as a result of the increased varieties.
The possibility for creating more mutations with the Society Finch seemed to be limited, looking at the existing theories about feather and color structure. Until a photo appeared on the Internet of two birds that looked like Society Finches. The photo was sent to Fred Panjer by an American bird fancier with the question if this mutation was also known in The Netherlands. The photo came from Japan and was called "pearl" mutation. The birds had a light gray cap, wings and tail and a warm chestnut color on the back, breast and belly. Curiosity was awakened and through contact with a (true) Japanese Society Finch breeder from Tokyo more information was obtained. The mutation appears to be enormously popular in Japan. This bird is known as a "pearl", because of the pearled throat and breast and because of the light pearl gray color that is caused by the mutation.
There are many stories about the origin of this mutation. According to information from Japan the first mutation appeared in 1982 by Isao Sekita. He discovered a young bird with silver colored wings amongst his dark brown Society Finches. There was also silver colored feathers on the body. This bird was paired to one of the parents and from this, more birds that showed the same mutation were produced. These birds were bred amongst each other and in 1985 the pearl, as it is now known, was created. From a different source this story changes a bit, by telling that Mr. Ikuina had discovered the mutation and that he developed it further together with Mr. Isao Sekita. Yet another source tells that the first pearl was discovered in a bird shop in Tokyo in the early 80's. Mr. Osamu Tamura had supposedly bought the pied bird and for years he tried to develop the mutation as a one colored bird on his own. In 1998 Osamu Tamura sent a number of these pearls to American Society Finch fanciers, these were the first pearls to leave Japan. The first pearls came to Europe in 1999. After exchanging several letters back and forth between Fred Panjer and the Japanse breeder Koichiro Washio, a case with several of the birds arrived at Schiphol Airport in June. These birds have noticeably lighter caps, especially the top of the head is a very light gray. Also the shoulders show light gray feathering, while the wing feathers and the tail have a distinct gray color. In combination with the warm chestnut gray color of the rest of the body, this makes for an exquisite looking bird with beautiful rich color. Fred Panjer started breeding with these birds, the colors and marking patterns belong to the pearl mutation in black brown. Even though some people, particularly Osamu Tamura are of the opinion that this mutation is only appealing in black (dark) brown, the combination with black gray also produces a bird that is definitely worthwhile.
At first sight, the "pearl" mutation seems to have a strong reduction in the black eumelanine, or even more realistic, appears to transform this into a more silver colored pigment. In any case, it is a different procedure from the way the black eumelanine is being transformed with the chestnut brown mutation of the bird. It seems to make sense to do some investigation to check if there is also a change in the structure of the feathers of this mutation. Besides, it seems that in some feathers as if the pigment has been deposited intermittently, and therefore it gives a speckled or spotted appearance. If the transformation of black eumelanine in the parent birds happens in such a way that it is concentrated in certain places, then those places will become lighter and this process creates birds that are rich in contrast. In combination with birds in which the black eumelanine is more evenly deposited, such as by our black browns and black grays, more uniformly colored birds may be expected.
Also in Japan the combination with black-gray, there named "pearl-gray" has gained popularity. These birds generally show a more uniform color. It was in 1997 that, according to Japanese standards, the perfect "pearl-gray" was bred after several breeding cycles. These birds glisten over their entire body in a silvery color that mostly resembles aluminum foil. The color markings of the "pearl-gray" show many similarities with the opal factor. Even though the birds are light in color, there seems to be a much larger concentration of pigment grains on the underside of the feathers. The deeper color is, so to speak, translucently covered by the light gray top upper part of the feathers. The young "pearl-grays" also have a darker skin color. The considerably lighter reduction can be seen on the wing feathers in the nest as the lighter wing feathers grow out of the darker colored wing skin. The Japanese breeders are still working on improving the appearance of the birds. According to them the difference in sex is quite obvious with the "pearl"-mutation. The hens are uniform in color, the cocks show more contrast. This seems to be the case with the clearwing mutation, where the difference in sex is also quite distinguishable in most birds. It is also remarkable that in these birds the dark shafts of the feathers come back in a much-reduced color after the first molt. The better young already have light gray shafts when they are still in the nest. In Japan the letters A, B or C classify the quality of the birds. The birds in the A category are the best and the birds in the C category are the lowest class. The birds that came to our country in June 1999 come from the Japanese breeders Eichi Konishi, Chyuzi Torizuka and Koichiro Washio. The young from these birds still show a large variation in color depth and contrast. In addition to that, the birds are not pure enough to use for breeding, therefore there are different colors appearing in the nests amongst those birds. The results of pairings with the Dutch full color birds were immediately noticeable. The pairing of a pearl cock with a black brown hen gave a nest of pearl and dark brown young right away. Without exception the dark brown young were all cocks, while the pearls were all hens. The pairing of a black gray cock with a pearl gray hen gave only black gray young, cocks as well as hens. These results point to a sex-linked recessive mutation compared to the wild form. The pairing of a light pearl-gray cock with a pure black gray hen gave very light pearl-gray hens immediately. These birds are so light in color that they appear to be dilutes, but since there is no dilute factor in the black gray mother, this cannot be the case. The conclusion is that the pearl mutation is able to cause a very strong reduction in color.
For the technical committee of the J.M.C., it will be a beautiful but difficult challenge (task) to describe this mutation in a standard. The Japanese, contrast rich bird is certainly a great asset to the color spectrum of our finches, as you can see in the enclosed pictures. The typical marking pattern with the hallmark silver gray head, wings and tail, in combination with the warm chestnut brown body and the pearled cheeks, throat, and chest, will certainly be worthwhile to standardize. Also in combination with gray, these birds seem to be a welcome addition to the society finch family. A more evenly colored variety in the gray series would probably also make a worthwhile addition. The combination with our evenly colored standard birds assures that the mutation takes place more evenly over the entire bird; the result of which can be seen in the photos. In the brown series, the breeding of evenly colored birds will be more difficult. The gray accents in the head feathers and wing and tail feathers will have a negative effect on the evenness of the color, certainly after the first big molt. Some years of experimenting are necessary to find out which possibilities the pearl mutation has to offer. In these experiments we have to be extremely careful with the characteristic appearance of the bird that came from Japan. If we loose this mutation through careless breeding, we will not be able to get it back easily and trying to get new Japanese “blood” is so costly, it won't happen so quickly again. However, the mutation should be tried for other variations. The results of which should be expected to teach us more about the new mutation, but also give us more information about the feather structure and color formation of the well-known mutations.
The first pearled Society Finch was shown by Fred Panjer during Vogel 2000 in Apeldoorn as the European debut. Also at the impending anniversary exhibit from the JMC, the organization for Society Finches and other Lonchura's, different variations of this new mutation will be shown. Note the date and place of this show in your agenda. On Saturday afternoon on September 30, 2000 from 14 -17 hr. in the club building of the Soester Birdlovers "Birdsong" Parallelweg 7b in Soest, you are cordially welcome. Also from other countries a lot of interest is shown for this exhibition.
At this show all mutations of the Society finch can be admired and there will also be many kinds of nuns, munias and mannikins. There will also be a sales booth for the purchase of the 25th year JMC anniversary book that contains, among other things, photos, descriptions and marking patterns of other society finch mutations. (See the book review "Onze Vogels" April 2000 Pg. 157)