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More
than Ten Primaries at the Domestic Pigeon
Koen
Joris and Axel Sell
Pigeons usually have ten primaries. Exceptions occur, with large
pigeon breeds more often than ten, and in small breeds fewer than
ten primaries in some individuals are observed.
Although the phenomenon has already been mentioned in the literature
at Darwin's time, no genetic investigations have so far been made,
apart from reports of sporadic observations.
In the official organ RÖK of the breeders' association of pets
January 2017 a comprehensive study based on about 500 observations
was devoted to this question.
Photos from RÖK Freude
mit Kleintierzucht, January 2017, pp. 8-11.
In the most comprehensive book 'Pigeons' from Levi it is assumed
that it is a dominant feature. Probably because of reports from
breeders that they got from supernumeraries besides some young with
normal ten primaries also some with more than that. This is to be
expected with a dominant feature from a heterozygous pigeon.
However, it is also the result of recessive features when there are
heterozygous potential partners present in a loft. A simple
recessive feature it is not, however, because there were too many
reports from the breeders, according to which supernumerairies mated
with each other produced some wild-type ones with 10 primaries.
Given the frequency of such observations this could not be
attributed to the incidence of impregnation as in non-individual
cages. A large-scale investigation, which could also reveal more
complex relationships, was thus overdue. Koen Joris from Belgium has
accepted this challenge. After extensive records with several
hundred observations in his loft, one could already conclude that
the previous explanations were insufficient and that at least two in
isolation recessive factors had to work together in order to achieve
more than ten primaries. The new hypotheses resulting from the
analysis of the data from the racing homer project were tested by
intersections with fancy pigeons from a breed and strain were
supernumerairies did not appear in the past, Gold-Bluewing Gimpel.
The empirical results of the Gimpel crosses in the F1, F2
and backcrosses had the best fit with a 3-factor model. Three
factors sn1, sn2 and sn3, which if standing alone are recessive,
have to act together. However, only two of them have to be
homozygous, which explains the occurrence of wild-type young from a
pair of supernumerairies. For those interested in color genetics the
crosses are a fine example of how gimpel bronze and the factor pale
responsible for the gold are reproduced in the grandchildren.
 
Photos from RÖK, Freude
mit Kleintierzucht, January 2017, pp. 8-11.
What does it mean for breeding in respect to primary numbers? If you
like to have a strain of supernumerairies, you will be able to get
one easily through selection. However, it is not to be expected that
the flight performance would be appreciably improved in racing
homers. Otherwise, the feature would have long been established in
the selection for performance. In his youth, the co-author
occasionally had a pigeon with more than 10 primaries at one or both
sides among his racing pigeons; they were no better and no worse
than the others, and have disappeared during time without trace.
In breeds in which the trait is undesirable, it should be avoided in
any case to use a sumernumeraire in the breeding stock. Even if the
direct offspring does not show the characteristic, they will give
the genes for that trait to their offspring, and the characteristic
will reappear in later generations. Whoever has the characteristic
only in some lines, which are breedably dispensable, should exclude
them as far as possible from further breeding. The cessation of the
feature by testing stock birds by test mating to exclude carriers of
the trait, is much more difficult in this case than for simple
recessive characteristics. With progress in molecular genetics that
might become easier.
Photo of an '11-penner' from the backcross of an F1 to a
supernumerary homer
A big thanks from the authors to the editors of the Magazine of the
Austrian Pet Association, which made the relatively large
contribution possible, including the documentation of the most
important data. Thus interested parties can match their own
experiences with our data and make use of the data also in their own
investigations of this and similar topics.
Literature:
Koen,
Joris, and Axel Sell,
Überschwingigkeit bei Haustauben,
RÖK Freude mit
Kleintierzucht, January 2017, pp. 8-11.
Levi,
Wendell M., The Pigeon, 1. ed. 1941, reprinted with changes
and additions 1963, reprinted 1969, Levi Publishing Company, Sumter
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