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GRIZZLE by Frank Mosca
 Tiger Griz King Homo tiger grizzles
From L-R: Tiger Grizzle blue King and (most likely) homozygous tiger grizzle racing homers

Grizzle is a term which implies an intermixture of black and white. Grizzled hair is hair which has both color and white on the same shaft. Another term we could use for it is salt and pepper. Grizzle in pigeons means the same thing, a mix of white and color on the same feather, i.e., the barbules of each feather are white and colored in a seemingly random mixture. It is this coloration which pigeon breeders usually refer to when they mention grizzle. Grizzle has been found to be partially dominant to wild type. That means it's visible in its heterozygous state, but that its phenotype (how it looks) in this state is different than how it looks in a homozygous condition.

The one breed most people probably think of when they mention grizzle is the Dragoon. This old English breed epitomizes the classic color and a blue barred grizzle Dragoon is truly one of the pigeon world's top achievements. (At least, I think so. I fell in love with Dragoons as a boy and I've never outgrown my fascination with them, even though I don't breed them.) Notice I said blue barred. That's because grizzle is a mutation which can be added to any pattern or color. Of course, it looks better with some things than with others, and in some cases it may not even show up because of other factors inhibiting its expression. For the moment though, let's concentrate on grizzle in the bar pattern on a wild-type bird. (blue-black pigment) If the bird under discussion is heterozygous for grizzle (G) what we see is a blue barred bird but one in which the ground color of the body has that grizzle coloration we mentioned above - pigment and white intermixed. Grizzle seems to inhibit the formation of pigment and it seems to do a better job of that in areas where the pigment isn't as densely placed as in others: on the shield of a blue or mealy pigeon, e.g., rather than in the bars of the wing or tail. Homozygous grizzle inhibits pigment formation even more so than heterozygous grizzle. A homozygous grizzle blue bar is often almost white over much of the shield and body with color remaining only on the upper head, edges of the flights and tail tip - the so-called stork marking, a pattern often seen in Berlin Highfliers. Since grizzle inhibits pigment formation or placement, it stands to reason that it can be additive with other mutations which also inhibit pigment formation, ash-red, for example. A homozygous or hemizgyous ash-red bird which is homozygous for grizzle is often mostly white with some red flecking in its juvenile plumage. Often such a bird molts to white or near white as an adult. These white birds can almost always be distinguished from recessive self white birds by their eye color. Recessive self white pigeons are invariably bull eyed. Homozygous grizzle ash-red whites are usually colored eyed -- the famous Paul Platz orange-eyed whites in rollers are genetically ash-red grizzles. Obviously, grizzle can also be combined with any mutation of the checker series and even though normal pigeon jargon usage sometimes dictates otherwise, there is absolutely nothing wrong with calling a bird a grizzle check, or grizzle T-pattern.

Spread inhibits grizzle to some extent. The reason for this seems to be that since spread adds more pigment to the feather it's obviously working against what grizzle is doing. A spread bird carrying grizzle often shows its grizzling just about the head rather than across the whole body. Recessive red also seems to inhibit grizzle. Many say that mottled recessive red birds are combination grizzle, recessive reds but I don't believe that - at least, not combination of classic grizzle (G) and recessive red. I've raised too many mottled recessive red birds and paired them to non-recessive reds . Seldom, if ever, have I bred a grizzled bird. Right now, Ken Davis - the Almondator -- is running a test to determine whether recessive red mottling is caused by a grizzle allele or something totally different, an unknown or unrecognized bronze for example.

W.F. Hollander found a fairly common allele of grizzle a few years back. This allele, he called it tiger grizzle, is usually found in those birds whose juvenile plumage is self (one color) but whose adult plumage is mottled. Jewel Mondains are an example of birds with tiger grizzle so are mottled Kings - found mainly in Europe. Hollander has postulated tiger grizzle is the original mutation with classic grizzle a later partial reversion towards the wild-type, but that remains just a postulation.

Undergrizzle is a recessive grizzle. For many years, fanciers had noted that some birds show a grizzling or lightening of the feather from the base of the feather to about a third of the way up it. I remember being told as a young man that this showed "a weakening of the bloodlines" since the color was fading away. Actually, it turned out to be a fairly simple recessive mutation which can be found in many breeds. Whether this grizzle allele is responsible for the recessive red mottling mentioned above is presently being tested.

Birds carrying grizzle mutations, especially tiger grizzle, are quite often among the first spotted and loved by beginning fanciers. These birds are often eye catching and because their phenotypes are varied they can create almost a flower effect in the loft. A father-daughter pair of T-pattern grizzle homers I have in my loft have bred: blue bars, heterozygous blue bar grizzles, blue checks, het. blue check grizzles, T-patterns, het. T-pattern grizzles; homozygous grizzles in all the foregoing patterns; one splashed blue check (apparently, they're also carrying some piebald); zipper frilled (chest frill) birds; and I don't think I've finished pulling everything out of them yet.

Copyright 1998 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. (Last updated 01/25/00)
 

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