BUDGERIGAR BREEDERS’ EXPECTATIONS

Running Time 110 minutes. Recommended retail price $29 plus P&H (Aust)

This new DVD on Budgerigars features John Scoble, Nigel Tonkin, Ken McLean and Mick Leahy in a series of lecture-style discussions. Presenters speak from personal experience and understanding, mostly standing in front of still photographs on a wall.

John Scoble begins the video by comparing and contrasting the original wild bird with the modern exhibition Budgerigar, including its increase in feather size and change of feather direction. The ‘long-flighted’ problem seen in the modern show bird is discussed in some detail, without ever digging into the root of the problem.

John’s style is relaxed and casual, and not always politically correct, such as his story of killing a snake threatening the nest of a wild Budgie. There are also numerous anecdotes and legends—John believes, for instance, that the Fallow mutation has superior night vision, like a Night Parrot, which should be taken with the proverbial ‘grain of salt’.

Ken McLean, a Budgerigar breeder with extensive experience in the thoroughbred horse industry, gives the primary presentation on genetic inheritance. Genetics is a complex topic, difficult for many people to grasp and, unfortunately, Ken’s presentation fails to cover this specialised topic sufficiently or accurately, meaning breeders with no prior genetic knowledge could easily be misled in a number of areas.

There is no discussion of wild type and its reference point for all mutations, while the categorisation of dominant type mutations into dominant, semi-dominant, incomplete dominant and incomplete semi-dominant is confused and confusing. Yellow-face Blue, for example, is reported as an instance of incomplete semi-dominance, which is not a recognised form of inheritance. The fact is that Yellowface Blue is a recessive trait, forming an allelic series with Blue to which it is co-dominant.

 Dark factor, Violet factor and Dominant Pied are all co-dominant mutations. This term is also known as Incomplete Dominance, particularly in Europe where it is the preferred term, but it is the same form of inheritance. Ken McLean labels these mutations as semi-dominant, a rare form of co-dominance where the double factor genotype is lethal—this is definitely not the case with these mutations in Budgerigars. The Spangle mutation is listed correctly as incomplete dominance in one part of the DVD and incorrectly as incomplete semi-dominance in another. These are just two of the numerous errors, misinterpretations and ambiguities presented. John Scoble and Ken McLean do not believe this mutation follows normal inheritance patterns for incomplete dominance and postulate that the mutation is carried within mitochondrial DNA. Mitochondrial DNA is unique within the body in that it is only passed from mother to offspring, with the father playing no role. But its function is purely with the running of the mitochondria (the power plants of the cell) and can have absolutely no bearing on pigmentation of the bird. There is no way that the gene for Spangle is carried in these organelles and if it was, you could not have a DF Spangle as the father cannot contribute. Their suggestion is an attempt to explain the presenter’s belief that the Spangle mutation does not always follow normal inheritance patterns. The claim of impossible offspring outcomes from certain matings is common amongst hobbyists and merely reflects cuckolding of nests or errors in record keeping. But it remains a popular myth for breeders who use it to fill the gaps in their own knowledge or explain the unexpected. Spangle follows normal laws of co-dominance (incomplete dominance).

Gene linkage is discussed briefly between Cinnamon and Opaline as well as Cinnamon and Ino. However Ken McLean incorrectly states that Cinnamon and Opaline are tightly linked and that Ino is barely linked at all to Cinnamon. This is in fact the reverse of the actual situation, with Cinnamon and Ino the best example we have in aviculture of very close, tight linkage, whereas Opaline is linked only loosely to these other two mutations.

Variegation is mentioned as a cause of unexpected pigmentation in some birds in a number of places on the video. The presenters use and understanding of this term is never really explained well enough, although comparison is made with variegation in Canaries. Yet, what canary breeders call variegation, is merely the degree of retained pigmentation produced by a Pied mutation and is nothing unusual. So a heavy variegated Canary is equivalent to a lightly Pied Budgerigar and a lightly variegated Canary is equivalent to a heavily marked Pied Budgerigar. The presenters in this video imply that variegation is something quite different, that it is a trait independent to the main colour mutations carried by the bird, which can alter colouration on a local level.

However, they are grouping together quite different traits which all have accepted explanations in a conventional manner. The variation seen in Pied mutations is a function of all Pied mutations, irrespective of the species of bird and are always subject to skilful selection by breeders. The bleaching of cinnamon pigment in Cinnamonwing Budgies is well documented across all species of birds with this mutation and has nothing to do with genetic action. And in a third instance where variegation is quoted, the changes are likely caused by a mosaic.

In discussing Grey factor, Ken McLean shows no understanding that the Greygreen is the base mutation and that it requires the addition of the Blue mutation to produce Grey as a combination. Instead he speaks of Grey as the mutation and that when mating it with wildtype Green you produce a ‘blended’ ‘co-dominant’ colour which is the Greygreen. There is absolutely no mention of the Blue mutation being required to produce the Grey phenotype.

John Scoble discusses the recessive multiple allelic series involving Greywing, Clearwing and Dilute mutations. In basic terms he explains how the different alleles interact, however he incorrectly adds Fallow to the list of alleles for this locus. Fallow is unrelated to these other three mutations and if mated to a Greywing, would only produce wildtype offspring double split for both mutations, not Greywing split Fallow as John believes. Black-eyed Yellow is recorded as an allele of this series but there is no recognition that it is in fact a Cinnamon Dilute combination.

The DVD’s primary message appears to be promoting the use of inbreeding to establish a strain of birds. Focusing on selection for positive traits and inbreeding back to superior birds with those traits, there is no mention made of the disadvantages of inbreeding.

What this DVD does illustrate is that, to be a successful breeder, you do not have to have a good knowledge of genetics—it only aids your understanding of what you are doing. For centuries breeders have manipulated and altered domestic animals to produce enormous variation in breeds, all without even a basic understanding of genetics.

John Scoble and his friends promote the same successful path of inbreeding to reinforce a trait. Better knowledge of genetics could in fact act as a hindrance, as it cautions the breeder against excessive inbreeding, without which we would not have all the different breeds of domestic birds and animals known today, including the enormous changes successfully bred into the modern exhibition Budgerigar.

Reviewed by Dr Terry Martin BVSc