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Genetics of ringneck, Dove color genotypes phenotypes, Feral pigeons

THE FERAL DOMESTIC PIGEON, Columba livia. 30 Jan 97

by

Wilmer J. Miller¹

Birds that we see in their natural habitat may be beautiful, interesting, thought provoking and delightful. There is one species, the domestic pigeon, now spread world-wide that has been long domesticated, perhaps for 4,000 years or more! It has provided food, fertilizer, entertainment, message delivery, and an increase in biological knowledge. It’s genetic variability is rivaled by few other species among the higher animals, (Drosophila, mice, chickens...)

For bird watchers such as COA and Audubon groups, these escapes from breeders pens that we call feral (wild, but from domestic stocks) are ever present in those artificial canyons we call cities and in those smaller cliffs and caves called towns. Such feral pigeons should not be ignored, but should be noted in counts and listings. Where else can you find such instructive variability in a wild bird?

COA and Audubon members should learn the colors and patterns evident in pigeons in the city environment and occasionally in the country associated with bridges and cliffs. What are these variations often seen? ....Red, blue, black, white, gray, grizzle, pied ...are all commonly seen colors plus the more rare yellow, indigo, laced, and many more that are more difficult to describe. But let’s be more exact.

Patterns² of pigment distribution are most immediately evident. The wild type is blue bar (2 black bars in the bluish wing). In the hand, or through binoculars, you should also note the whitish rump and perhaps you can see the whitish outer tail feathers on each side of the spread tail. The bluish tail has a near terminal black band.

The genetically dominant black or spread pattern is self evident black all over, including flights and tail feathers.

A mutant locus on the same chromosome as spread, but nearly independent, is the best example of multiple alleles for genetics students, the checker or check series of multiple alleles. The top dominant is the T- pattern (gene symbol C^T) which is almost as black (a few light edges or triangles as "check" in the wing shield area) as spread pigeons. However, T-pattern birds have regular flights and tail with the near terminal band. Recessive to the T-pattern is another mutant allele, check (C), controlling several triangular checks of light gray or "blue" in the blacker wing shield area. These two types actually intergrade, possibly from modifying factors or more likely from intermediate alleles. Nevertheless, one can almost always distinguish them in feral birds. A third allele recessive to both T-pattern and check is the wild type bar pattern (+). Finally, the 4th allele, recessive to the other 3, is the barless (c). Barless is bluish like the wild type, but it lacks the bars. Barless is only rarely seen in feral pigeons. The gene symbols in order of decreasing dominance are C^T> C>+>c.

Another pattern type is the gazzi white pied with a colored head, upper neck and wings and tail, but a white back, breast and ventral color. It is recessive to the wild type and rare in ferals. White flights is rather commonly seen in feral pigeons. It is sometimes associated with a white ("bald") head, and has a bit more complicated inheritance.

White pigeons can be seen feral (one kind is recessive); but most often feral white birds are pied (piebald) with scattered patches of pigmented feathers. While the inheritance is complex, it is some kind of partial dominant in effect. Grizzle is a codominant with white streaks on the head and neck and often elsewhere when one dose of the mutant is present. When homozygous (2 doses of the grizzle gene), grizzle is nearly pure white with streaks of color.

Now Colors: There are 2 kinds of red. One is a recessive red with dark gray edges about the tail and rump and a bit in the wings. It covers up (hides) pattern types and some of the other colors. So it is called epistatic in genetic terms. This recessive red is uncommon in the feral state as are most of the recessive mutants. Rather common is the sex-linked dominant ash-red. The otherwise bluish "ground" color is gray-like with reddish tones. The bars are red. The red in the checker pattern or T-pattern is not rare in feral pigeons. When ash red is combined with spread the entire bird is gray or ash color with only very faint red showing sometimes in the mongrel birds. Allelic to ash-red is brown (called chocolate when combined with spread). Brown is recessive to ash-red or blue. [Female birds have only one dose of sex-linked genes (are hemizygous)]. Males heterozygous for ash-red and blue have black specks especially in the tail and flights. So if you see such an ash-red pigeon with black flecks, you know it is a male. Males heterozygous for ash-red and brown have brown flecks.

Also sex-linked, but at another locus, is dilute. It is recessive. Combined with either type of red it is called yellow (and ash-yellow).

Still another locus on the sex-chromosome is almond (or magnani). This is a codominant, and as a single mutant drastically mixes red, brown, blue, black, and white specks and patches. Two doses of this gene is detrimental with bulging eyes and poor vision, as well as near white plumage.

Two other color mutant common in feral pigeons are smoky and dirty, but they have small effects more difficult to notice. For example, smoky gives a paler base to the blackish bill plus no white in the outer tail vanes.

These are the colors most likely to be noted in feral pigeons. Many others can be seen in fanciers lofts. Some of these are faded (allelic to almond), pale (allelic to dilute), reduced, opal (dominant and recessive types), indigo, milky, pearl eye and more. You might see also a crest or grouse legged birds now and then.

Combinations of color mutants yields many more interaction colors, with many beautiful effects.

Now, what are the colors and patterns in your neighborhood?? What is their frequency? Such data could result in a scientific paper! [For example: Frequency of colors and patterns of feral pigeons in Belo Horizonte]

²I obtained most of my genetic information about pigeons from Dr. W. F. Hollander, now retired from the Genetics Department of Iowa State University. I confirmed much of this information in my own experiments at the Universities of Wisconsin, California and ISU. Dr. Hollander and I have published several scientific papers together.

A shorter version appeared in Portuguese in UIRAÇU Ano 1, No 1, Nova Série, Junho 1997. Informativo do Clube de Observadores de Aves; Nucleo de Belo Horizonte p. 7

[Uiraçu is a harpy eagle.]

Also in the Ames Audubon newsletter......

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Genetics of ringneck, Dove color genotypes phenotypes, Feral pigeons