Recessive opal (genetic symbol o) is about the only color modifying mutation that racing pigeons breeders can pretty much claim as their own. It's practically unknown in the show pigeon community, though a few breeds, notably standard Fantails, have had it added to their gene pool since the mid-1980's. Racing homer men know recessive opals as mosaics (mosaiques), and sometimes even as "chocolates". The mutation was recognized as something unique and its inheritance worked out by W.F. Hollander in the 1930's. Because recessive opal causes an interplay of colors in the checking, he named it from a fancied resemblance to the semi-precious gemstone.
Most of the flyers I've known over the years have liked opals for the touch of uniqueness they add to a loft. As far as racing ability, they're the same as any other colored bird. Some are good, some aren't. Since there are so few of them overall, they do tend to be remembered. So, what you find are people praising or despising them as a result of what happened to that "mosaic I had a few years back."
The birds themselves are usually quite attractive, though there's a good amount of variation in coloring from bird to bird. Most have lightened tail and flight feathers. Their bars and checks are pinkish-bronze-grayish. A few birds are near-perfect mimics for Ash-reds. These are the ones which confuse people who believe they've reared Ash-reds from a pair of blues in an individual breeding compartment.
Recessive opal is an autosomal recessive mutation and is not sex-linked. All birds, male and female, need two copies of recessive opal (i.e., they must be homozygous for the trait) for it to show its effect. Pairing recessive opal to recessive opals produces all opal youngsters. A recessive opal of either sex paired to another colored bird not carrying opal will produce all non-opals, though all the young will carry opal. This inheritance makes it easy to distinguish recessive opal in breeding tests from two other mutations, and sometimes look-alikes, reduced and Dominant Opal. . Recessive opal is also linked (i.e., it is close by on the chromosome) with Checker and both are often inherited together almost as a unit factor.
I've flown at least a dozen recessive opals myself over the years. My family of birds at that time, Shortfaces, a local California strain, produced the really attractive pinkish-bronze type, and ultimately traced its ancestry back to the Bastin family of pigeons. Bastin lived and flew his birds in Belgium in an area around Liege. Recessive opal birds all seem to spring from birds from that area, but, naturally, records are difficult to establish over a hundred years time. It does appear, however, that one of the birds originally used as a cross for the modern racing pigeon carried the recessive opal mutation. As racers became more popular, the mutation spread. Hollander believes recessive opal has often been carried hidden in Ash-red birds, and may even have been unconsciously selected for, since it seems to help lighten up the neck blend area of "silvers".
Recessive opal hens do occasionally show some weakness. I've also heard from friends that recessive opals don't seem to live as long as wild-type colors, but these reports are scattered, and occasionally inconsistent. I believe some of the inconsistency results from confusing Dominant Opal birds with recessive opal ones. I never saw either fertility or longevity problems in my own stud. Of course, those were birds flown in competition and weak ones were selected against long before they reached the breeding loft. It's also possible, though never shown to be fact, that there are slightly variant mutants of recessive opal.
Homozygous recessive opal combined with Spread (in the blue series) produces one of prettiest (at least, to my way of thinking) colors. I call it Pewter. Spread recessive opals tend to be a silvery color throughout the whole body with the iridescent neck blend area being a shiny metallic silver. Recessive opal brown is simply "yucky". Recessive opal Ash-red is mostly indistinguishable.
There is a possibility of some confusion with a look-alike mutation to recessive opal, Dominant Opal. However, they are two very separate things and each inherits independently of the other. Dominant Opal also has a lethal factor associated with it. Homozygous Dominant Opals either never hatch, or if they do, seldom live to fledge. Those extremely rare few that do get out of the nest, almost never live to breeding age. Dominant Opal is now found in Racing Homers, but is still very scarce. It was added in the last twenty years by a few people in an attempt to create white-bar and white check birds. It's much more common in show pigeons of central European ancestry, e.g,. Strassers, Saxon Pouters and many of the German Color Pigeons.
Copyright 1997 by Frank Mosca. This work may be downloaded or copied for non-commercial individual use only. All other rights under copyright are retained by the author.