By Cyril Rogers 1984
Whilst visiting a friends aviaries I saw amongst their many coloured budgerigars in residence several olive yellows carrying that beautiful soft orange yellow shade which reminded me how scarce these attractive birds have become. Although a sprinkling of the various olive forms are mostly to be found in mixed colony breeding aviaries very few specimens seem to find their way on to our show benches nowadays. There seems to be two main reasons for the decline in popularity of all the olive coloured varieties, one being the ease in which the somewhat similar grey green coloured forms can be produced and the second is the difficulty in getting substance in these dark coloured kinds. Olive yellows and the two associated varieties, the greywing olive greens and the yellow wing olive greens are extremely interesting birds to breed, improve and exhibit and offer great scope to breeders who like an all round challenge.
Before I proceed to give some suggestions for breeding good coloured olive yellows I feel I must explain just how they reproduce and their hereditary characters. They belong to the recessive dilute green (yellow) family and their attractive rich colour is due to the fact that they have a double quantity of the darkening character D in their genetic make-up. Olive yellows are in fact light yellows to which a full quantity of the dark character has been added and this can change the light yellow colour into a rich orange shade. It should be noted that the dominant dark character is not a colour in its own right but a character that in conjunction with another colour alters the depth and shade of that colour. The dark character can be had in either a single quantity which gives the dark colours, i.e. the dark greens and the cobalts or a double quantity producing the olive greens and the mauves.
Two Grades of Yellow
Now for a more detailed description of the colouring of olive yellows so that breeders can recognise specimens when seen. The Budgerigar Societys Colour Standards gives two grades of yellows - the clear and the suffused.
From the descriptions it will be seen how the grey yellows can, and often are, mistaken for the more rare olive yellows. Like all yellows the olive yellows can be had in the clear and the suffused kinds. In overall colouring the olive yellows are much deeper and decidedly richer in colour than the light yellows (buttercups) with the body colour a warm orange yellow and the rump a golden olive tinted shade. With the suffused kind the body shade is more of a golden olive tone with the rump showing a much deeper colour and the tail more heavily tinted. The grey yellows are much more of a dull mustard colour and quite distinct from the lovely warm shade of the olive yellows.
Olive yellows inheritance is quite straightforward when only yellow series birds are being used and follows the general Mendelian rules of inheritance. There are of course a great many mating of other colours that will give varying percentages of olive yellows when the parent birds possess the necessary colour characters needed. The following rules will show the manner in which olive yellows pass on their colouring.
1. Pure olive yellow mated to pure olive yellow will give all olive yellow young.
2. Pure olive yellow mated to pure light yellow will give all dark yellow young.
3. Pure olive yellow mated to pure dark yellow will give half olive yellow and half dark yellow young.
4. Pure dark yellow mated to pure dark yellow will give a quarter light yellow, half dark yellow and a quarter olive yellow.
The word pure here indicates that the birds are not carrying any other colour characters in their genetic make-up.
Other Varieties From Splits
If the parent birds used happen to be split for other colour characters then varieties of yellow birds can arise such as cinnamon or opaline light, dark or olive yellows. There is no visual way in which pure birds can be distinguished from those, which are carrying other colour characters. In a controlled breeding stud any hidden colours are invariably revealed in the course of time. The most frequent colour carried by yellow series birds is white and in the case of olive yellows results in the appearance of white mauves. Although white mauves can be used in the breeding of olive yellows their use will only cause an increased number of them to be produced resulting in fewer olive yellows.
I am sometimes asked how a start can be made when the would-be breeders do not possess any examples of the olive yellow in their studs. Let me say right away that it is not easy and requires considerable perseverance and patience to produce a nucleus of the desired coloured birds. One way to start is to obtain a pair or so of genuine dark yellows, which seem to appear quite regularly amongst the young of normal pairs when one partner has a single dark character and both are split for dilute. The expectation of pairing together two pure dark yellows is 50% dark yellows, 25% olive yellows with the remaining 25% being light yellows which are not required in this exercise.
Such matings will give the breeder an average of one olive yellow in four during the first season and in the following year these birds can be paired to dark yellows again giving some 50% of the desired coloured birds. Their numbers can be further increased by mating together some of the surplus dark yellows as in the first season. In the third year a series of olive yellow matings can be made with a certain amount of selection for obtaining the near clear deep orange body shade. It is very important that from this period a selection of the best coloured stock is made every year. If during the pairings the cinnamon character is incorporated via either cinnamon light yellows or cinnamon dark yellows it only takes a season or two before the very pleasing cinnamon olive yellows can be produced.
Good Overall Colouring
The few results I have seen coming from the crossing of olive yellows with yellow wing olive greens or yellow wing dark greens were very good for overall colouring. Some of these birds had an exceptional depth of body colour together with quite good clear wings giving a most attractive appearance. Most of these birds were very tight feathered which gave them a rather less substantial look but I feel this could be corrected by the choice of suitable breeding partners.
With all the varieties that carry a double quantity of the D character in their genetic make-up it is found that they are more difficult to improve in substance than those where the D is absent. It would seem that the only sure way to achieve this is to periodically mate double dark to single dark with the single dark being bred from a single dark and a non-dark (light yellow, light green, sky blue etc).
Full body coloured greywings, a composite form very few present day budgerigar fanciers have yet to see. These delightfully coloured birds are a combination of the greywing and clearwing characters in one bird, they have the greywing undulations of the greywing set off by the deep brilliant body colour of the clearwing. In the heyday of the greywings and the introduction from Australia of the clearwings (which included some full body coloured greywings), only a very limited number of full body coloured greywings were bred in this country and very few of these found their way on to the show benches. As far as I know it is a very long time since an example has been shown in this country although an odd specimen or two have been bred in mixed coloured aviaries.
At times heavily wing marked clearwings have been wrongly called full body coloured greywings and although such birds have several features of the full body coloured greywings they are not the real composite birds. By test pairing it is quite easy to discover which are the genuine birds and which are poorly coloured clearwings. When a full body coloured greywing is paired to a dilute (yellow or white) half the young will be greywing/dilutes and half clearwing/dilutes. On the other hand when a poorly coloured clearwing is paired to a dilute all the young will be clearwings or if the clearwing parent is split for dilute then half will be clearwings and half dilutes. It should be noted that a clearwing cannot be split for greywing or vice versa and that a full body coloured greywing cannot be split for dilute.