Here's an article written by Paul Girvan a few years back.
Every once in a while, a question from an eager novice or newcomer appears in Cage & Aviary Birds, asking how to breed mules from a Goldfinch or Siskin that they have just acquired. The limited space available means that the answer is usually restricted to basic hints on success in the art of muling.
For many years now, i have taken great delight in trying to produce miniature mules. At first, i did so because i was fascinated by the idea of going against nature and breeding something both beautiful and unique. More recently, though, I have concentrated on providing quality miniatures for the show bench, and while i won many best miniature mule awards at my local C.B.S shows and even at our all britsh shows, my proudest moment with miniatures had to be winning best miniature at the prestigous Irish Bird Breeders Society show in Dublin in 2004 with a Siskin mule.
Hundreds, probably thousands,of miniature mules are reared each year, and their breeders should be applauded, as not everyone who tries is successful. There is probably no "right way" -and definitely no "wrong way"- but i would like to highlight two methods that have rewarded me.
Both involve unflighted Finches and unflighted Canaries. Although a proven muling finch can be relied upon to carry out his duties even with a Canary that has previously been mated with its own kind.
After the young Canaries have moulted out and cocks and hens have, hopefully, been correctly sexed, i like to introduce the finch to his intended partner. Ideally, this should be in a double breeding cage, with just one perch situated at one end of the cage. This keeps both birds fit and flying from the perch to the end of the cage and back, usually resulting in approx 2 metres of flight.
This is especially important when Siskin cocks are used, because they tend to put on weight through lack of exercise and overfeeding on Niger and Hemp seed,which they will seek out above all other seeds, resulting in obese birds that are useless to any breeding programme. They should be restricted to a good Canary mixture with no added Niger or Hemp.
Pairs are kept together all winter and ,hopefully ,come spring, the combination of familiarity, and the fact that they have shared the same perch for months, will have created a bond.
If the birds have bonded, the signs will be obvious come April, when the Finch cocks will be seen feeding the Canary hens as their begging cries become more persistant as the breeding season approaches. This is more evident with the Siskin cocks, which seem to be more tolerant of our presence in the birdroom. Goldfinches ,however, seem more shy, and a bond can often only be confirmed by peering through the corner of a window or the gap of a half-opened door.
When the hens are ready to go to nest, they will be seen carrying mouthfulls of whatever nesting material is available to them : wood shavings, feathers or newspaper. When this is witnessed the nest pans can be introduced along with proper nesting material.
This is an important stage for me. At this point, I treat my Siskins and Goldfinches differently. I am sure that other breeders have their own way, but this method works for me, with 23 miniature mules bred from 4 hens in 2004.
When the nest is complete, i split the Siskin cock and Canary hen by way of a wire divide every evening. I reintroduce him in the morning, after i have replaced any eggs laid with dummy ones. This is done until the clutch is complete.
The Siskin cock is then kept apart as before, because Siskins, above all other british finches, have a tendancy to eat the eggs and cannot be trusted !!!!.
However, more often than not the Siskin can be relied upon to fertilise the eggs in the first round. All going well, he can be reintroduced once the young mules have hatched, where he will happily carry out his parental duties [help with feeding the young] even after the youngsters have left the nest.
I use different tactics in trying to breed Goldfinch mules at this stage. Instead of leaving the Finch cock with the Canary hen, I shut him off, again by use of a wire mesh divide, and I run a Canary cock with the hen until her clutch is complete. I do this firstly, because I can obtain young Canaries for the following year, and second, as the Goldfinch sometimes does not come into full breeding condition until May: eggs laid before this are usually clear.
When the young Canaries hatch- and not before, because Goldfinches, like Siskins, are partial to eggs- the finch can be returned to the hen.
One of the benefits of my way with Goldfinches is that, when the hen is ready to go to nest for her second round, the Canary cock to which she was previously mated can be brought into view. I do this by way of an all-wire cage suspended from the ceiling. With any luck, she will respond to his singing, and the Finch will successfully mate with her, resulting in a cluth of fertile eggs.
This should be done four or five times during the course of the day or evening, for no more than ten minutes at a time. It is also important that the fancier leaves the bird- room at this point as the Goldfinch- and who can blame him? - likes his privacy.
In producing show quality miniature mules, my best results have come from pairing yellow Siskin cocks to yellow green Fife hens, or yellow Goldfinch cocks to yellow half Fife, half Irish Fancy hens.
Many people advocate the use of coloured (red factor) Canaries. In my opinion, whilst these tend to produce quite colourful miniatures, when the Goldfinch is used, the offspring tend to be on the large size and do not quite catch the judge's eye. Maybe if the smallest intensive red hens were used instead of today's exhibition reds, which, to me, seem to have grown larger, some nice eye-catchers would grace the show bench.
I hope this article helps other fanciers, be they newcomers or 'old hands', to be successful and inspires them to pick up a pen and share their knowledge with all of us.