Inbreeding or Outcrossing?

This extract is taken from "Practical inbreeding" by W. Watmough, printed and published by Watmoughs Limited, London. reprinted July, 1982 (sixth edition).

Inbreeding with birds

The principles of inbreeding are applied somewhat differently to birds compared with the method of their application to animals-that is with the exception of poultry.

In the case of pigeons, budgerigars, canaries etc, the youngsters are produced from pairs, whereas, of course, with horses, cattle, dogs, rabbits etc, one stud male may be mated to a series of females within a comparatively short space of time, and in poultry one cock is run with a number of hens in a breeding pen.

The object of Inbreeding is to produce in excelsis the good properties of the birds which are being used, and avoid, as far as is humanly possible, intensifying faults or constitutional weaknesses.

By bad inbreeding one can with similar facility fix faults as by good inbreeding one can fix desirable features. Thus Inbreeding may be said to be a two-edged sword, and it is essential to use one edge only, an ability not difficult of accomplishment if the owner uses common sense.

Selection and elimination

The golden rule of inbreeding can be expressed in two words selection and elimination: selection of the right mates as indicated by appearance and pedigree; ruthless elimination of any bird that is for any reason  undesirable.

The outcome of an inbreeding plan "WiII give satisfaction or dissatisfaction according to the quality of the birds used in the breeding team each season - that is the quality of the related birds mated and their suitability to each other as mates, judged by both appearance and pedigree.

Close inbreeding must never be undertaken unless the fancier Is convinced that the birds he uses are themselves possessed of the qualities which he desires to fix in his family; and he must assess their merits not alone on their appearance, but on his knowledge of the appearance of their ancestors.

In breeding livestock pedigree is almost as important as external properties. All families have their good points and their bad points. The best families have the fewest faults; the worst families have the most faults. I am not interested in the worst families.

When laying the foundations of a strain it is desirable to begin with a few pairs of birds of the best possible quality, those with few failings and obvious pleasing features. They need not necessarily be big winning specimens purchased at very high prices, but they must be at least what we fanciers describe as good reliable breeding stock, possessing among them all the desirable points of the breed and few bad ones, of which they will have some, as I have never yet seen the pertect bird or animal. But the weaknesses should be in minor points only; major failings should not be tolerated. The moral is to buy the best birds you can afford at the outset and have few pairs of really good ones rather than pairs of inferior ones.

Making a cake

I will repeat the analogy which I gave when I lectured on breeding at the World Budgerigar Convention, held in Harrogate in August 1954:

If a housewife is to make a cake she must have the right ingredients or the cake will not be a good cake. More than that: she must mix those ingredients properly, and it is the mixing which is, when applied to livestock culture, so tremendously important.

The good ingredients In our cake are the birds with which we start. The mixing is the selection of the mates so skilfully that in the course of time we have a strain which breeds winners with regularity.

But In our cake mixture there will be some ingredients which we do not want in our finished cake. One can eliminate these by inbreeding linked with strict elimination. In the early stages of the carrying out of an inbreeding plan there will appear youngsters which display faults, and are themselves inferior to their parents. The faults are the family failings not necessarily to be seen in the parents but carried by them latently.

It is because of the appearance of such youngsters as these in the early stages of inbreeding that so often inbreeding as a practice is criticized, whereas it ought to be praised for this very reason. If the parent birds had not been related the failings might have remained latent Indefinitely, whereas they have now come to light and can be eliminated.

The youngsters from which the fancier will breed will be those which are representative of the best qualities of the familythose that are cast out representatives of the worst features of the family. Inbreeding has brought the dross to the surface. Continue with this process of segregation, and in due course you will have birds which carry hidden practically no faults and which are of good appearance themselves, and which, therefore, are capable of breeding high-class progeny. They are indeed as breeding specimens what they seem to be, as distinct from a bird which looks equally as good, but which is Inferior as a breeder because it carries serious latent faults. Such a specimen as this is the frequent result of an outcross. To put it briefly and simply, inbreeding produces stock which is homozygous for its own good properties--outerossing more often than not stock which is heterozygous.

Inbreeding does not create

Inbreeding Itself does not put anything in. It does not create either good points or bad ones. It only makes the best of what is there. Hence the need to have all the good points (the ingredients of the cake) at your disposal, with the object eventually of condensing them all in. the best birds you breed. The specimen that has them all, and as near none of the failings as makes no matter, is one of those outstanding Individuals which become famous.

To inbreed with poor birds would lead to the production of a strain of inferior quality, even though the birds bred would all be of one general type because of the effect of Inbreeding. The successful inbreeder produces birds all with a family likeness, but they are of high quality, not mediocre.

Later in this book I shall give examples of livestock owners who have achieved outstanding success without introducing an outcross at all; and there are some who aver that an outcross should never be necessary. Enthusiastic as I am about inbreeding, I cannot entirely. subscribe to this opinion, and I do not dogmatically assert that no one should ever Introduce into a stud an unrelated bird, in spite of the risks attendant on outcrossing. The need can arise if the owner has some good quality lacking in the birds with which he commences to found a family.

In my own experience, however ruthless the elimination and meticulous the selection, there can come a time when the inbreeder notices that a certain failing is observed rather frequently in his young birds. This does not always happen, but it Is an occurrence which has to be dealt with when it does. And the only method is to bring in an outcross in the way which I shall describe in Chapter VII, Outcrossing.

Degree of relationship

When inbreeding with budgerigars or pigeons (of which I own studs) I am not so concerned as to whether the relationship between the members of a mated pair is near or far as I am with the suitability of the two birds as mates. I don't deliberately breed from very closely related birds because they are closely related; I prefer a rather more distant relationship if I can achieve my object. As a matter of fact, after a few seasons of skilful inbreeding one can be so sure of the high quality of the pedigree of each member of the breeding team-so certain that there are no undesirable latent properties-that a point is reached when pedigree can almost (not entirely) be ignored and mates selected by analysis of visible qualities only.

I am often asked if there are any particular relationships which I favour, provided the two birds to be paired satisfy as regards their appearance. I can only answer this in a general way, as will be understood In view of what I have said in the last paragraph. I like uncle and niece, aunt and nephew, cousins, father and daughter, mother and son, grandfather and grand-daughter, grandmother and grandson. I particularly favour half-brother and sister when the parent of both is a bird of outstanding merit.

I never mate brother and sister unless the two birds are of exceptionally high quality. The offspring of brother and sister can only have in their genetic composition the characteristics of the two parents reassembled, and you are not likely from such a mating to produce a bird better than either of its parents. On the other hand, a young bird bred from father and daughter, for instance, can have a double dose of a particular desirable quality carried by the father, as I will explain more fully in Chapter V.

C A House in Inbreeding stated that a fancier should concentrate on improving one property at a time until he has covered all the points and produces specimens approximating to perfection. To use his own words, he said:

'Build up the fabric bit by bit. My experience is that you cannot reach a certain point as quickly if you attempt to do it all at once as you can if you make slow and sure progress by doing a bit at a time, and this, I know, is the experience of our most skilful breeders!

Realizing that if this advice were adopted it would mean that the producing of stock of the highest quality would be such a lengthy process that no one could happily contemplate it, when I revised Mr House's book I made the following comment:

'I think Mr House's advice in regard to dealing with one property at a time was not meant to be taken quite literally. Experience has taught me that if inbreeding is skilfully and systematically employed one can, season after season, improve all the properties. If a breeder were to concentrate on one particular quality to the neglect of all others, it would obviously take very many years to produce specimens good in all points. And I know that when Mr House wrote Inbreeding he did not really intend to convey the impression that one property only should be dealt with at a time, but what he did wish to convey was the necessity *when selecting mates and formulating a breeding plan of giving priority to that feature in which the strain is weakest. Later in his book Mr House supports the view which I have here expressed.'

Patience Is needed

Many young fanciers are in too big a hurry to breed many winners. They anticipate establishing a family of merit within say a couple of seasons. While they may breed a few winners in their early days, they must not expect to own a strain of their own capable of producing many first prize birds, and almost every bird they breed Itself a potential parent of winners, until three or four seasons have passed. They must have patience. They must carefully and skilfully build up the edifice they visualize when they start. Then in due course they will have their full reward. As a general statement, I would say that the period of time taken in reaching the objective is governed by two factors of equal import - the quality of the foundation stock, and the ability shown by the breeder in selecting and eliminating.

There are divided opinions as to which is the more important member of a pair, the cock or the hen. Broadly, my view is that they are almost of equal importance, but if I have a leaning it is in the direction of the hen, though according to genetic teaching, one sex has no more power over the quality of the offspring than has the other sex.

Why then have I any preference for the hen as a breeding force? Am I illogical? I will try to analyse my own thinking about this matter. The hen is, as It were, the soil from which the plant (our young bird) grows. And the strength of the plant Is governed to a great extent by the quality of the earth from which it springs. To carry on with the analogy, if the hen is strong and vigorous with her inherited good features developed to the maximum (in short, she is good earth) it automatically follows that her babies will themselves have such constitutions, and that the good qualities which they have inherited will develop to the fullest possible extent.

In considering this angle of the subject it has to be appreciated that good points inherited do not always show in a bird or animal as fully as they would do if there were no impaired development, and in this context I am not referring to that obvious Impaired development due to illness or malnutrition, but to the same circumstance in a much smaller degree attributable to a prenatal or congenital weakness consequent on a similar condition in the dam.

This is not dogma, it is theory, but it is supported by my observation of many studs of birds and animals in the halfcentury in which I have been interested in livestock.

Almost invariably have I observed that a breeder who owns females Inferior to his males makes little progress, whereas I have seen success achieved when the males have been of a little lower quality than the females.

In this connection, I notice so often a bad mistake made by budgerigar fanciers in particular. They buy a high-class cock probably at shows where they have red tickets on their cages -- and then, perhaps late in the selling season, they try to purchase suitable hens to mate to them. Very often the hens are not so good as the cocks, and the youngsters that are bred are disappointing.

Foundation birds

Sometimes we discover that we are the owner of a bird which is exceptionally prepotent. For the sake of illustration we will assume it is a cock. It may not be one of our big winners. It may be inferior in exhibition or racing qualities to its own brother, and yet it breeds youngsters of surpassing merit. In fact, it is a specimen in which all the good properties of its family are embodied and it carries no failings either visible or hidden. It is completely homozygous for all that is good in the breed of which it Is a member. Even when mated to inferior hens, It begets good looking youngsters, though it should never have a low grade hen as a mate for this reason: The young birds bred from this invaluable cock and comparatively poor hen, although they may be good performers either in the show pen or in the air, cannot be expected to be good-breeding stock because of the unavoidable influence of the dam on their genetic constitution.

Now this is prepotent bird, which probably never breeds a youngster that displeases, is what can be truly termed a foundation sire.

When once the bird breeder discovers that he is the owner of that invaluable, one-in-five-hundred individual, a foundation sire (it can be a dam), he can establish a line within his own inbred family by breeding daughters and grand-daughters back to the father, or the father's best sons, grandsons and so on-in fact, always going back to direct line descendants of the foundation bird on which the line is being established.

This brings me to the suitable point at which to end this chapter and pass on to Inbreeding with Animals, because to the animal breeder the use of foundation sires (sometimes dams) is of the greatest importance.


As I have said earlier in this book, I am not one of those who asserts that outcrossing is never necessary, and I do not want my readers to get the idea that two unrelated animals or birds can never breed an outstanding youngster. Great winners have been so bred when the mated parents have 'nicked', which, of course, they sometimes do. But among those winners there have been many that have failed completely ever to produce offspring of merit.

Personally I do not outcross unless circumstances force it upon me. I know that there are cases where abundant success has been achieved without an outcross ever having been made, and to some of these I shall refer in Chapter Vill.

But even so, I contend that however skilful the inbreeder may be, however meticulously he may exercise care in avoiding fixing to some extent any faults, constitutional weakness, infertility or other heritable characteristics, sometimes after a period of inbreeding a failing unexpectedly appears. Suddenly some of the youngsters fall somewhat In a particular point or he may realize that he can't make any more improvement in a certain feature, because none of the animals he has been using has had that feature sufficiently good for the breeder ever to produce it from his present stock.

Either of these occurrences must be accepted as a red light, and the owner must act without delay. The time has arrived for an outcross or semi-outcross to be made, the latter preferred if it will fully serve the purpose.

For the sake of illustration, we will imagine that there is a decline in size in a breed in which smallness is recognized as being undesirable. We will assume that we are compelled to introduce an unrelated animal, or bird, as the case may be. The individual purchased must be a really big one, and not deficient in any of the other properties which we have well established in our own stock, though he may carry weakness in one or more of these latently, because of an ancestor or ancestors so failing, which, of course, is the reason why outcrossing is dangerous.

To counter the possibility which I have indicated we must convince ourselves, if that be possible, that the relatives of the outcross do not fail in other properties, and are also biag ;b!irds -in other words, that they are of very good general quality. If the outcross comes from a home in which correct inbreedin has been practised it will be all the more valuable and less dangerous, because it is more likely to be prepotent for its own good properties.

Blending the outcross

Having purchased the outcross (which we will presume is a male, though this is not a necessity) we have now to graft his good qualities into our own inbred family; and this is how we can do it:

1.  Mate him to the most suitable female in the stud. Mate the best of the young females bred from this pair to her father. Their offspring will contain a double dose of their father, and when mated to other members of your own family should produce young ones which reflect the benefit of the outcross.

2.  Mate the outcross to two females, thus producing half-brothers and sisters, which, when mated together, will have children that contain a double dose of the outcross, and which in turn can be used with similar beneficial effect to those produced by method 1.

3.  Proceed with the intensifying of the outcross's good points (particularly the property, the improvement in which was the purpose of his being introduced) by mating the best granddaughter back to her grandfather (the outcross). This system of breeding back to the outcross can be continued if the new blood brought in has had the desired effect.

4.  Employ what is known as 'grading', which term I believe was first used in America in connection with a method of introducing a new line to an established line. This is described by Wendell Mitchell Levi in The Pigeon, the most informative book on this species ever published, as follows:

'Outbreeding, sometimes called outcrossing, is the introduction into a pure line of a bird or birds of another breed or variety, only one or a few matings in order to secure from the breed outcrossed upon some particular character desired, or to Infuse into the pure line a dash of new blood for purposes of vigour. The progeny of the outcross are mated back into the pure Iine in successive generations until the percentage of blood of the outcross is practically negligible.

'This method of breeding is useful in introducing into a pure strain some desired characteristic which it does not possess or in which it is weak, provided the characteristic is recognizable for the purpose of selection.

'Grading or grading up is quite similar to outbreeding but differs slightly from it in the breeding programme followed after the first outcross. While in outbreeding an outcross is made from one's strain upon a bird or birds, and the progeny mated back into the original strain, in grading an outcross is made (usually, upon a male) and the progeny mated back to this male rather than to the original strain. Thus, in outbreeding, new blood is added in small quantity to the original strain, while in grading the original strain Is gradually replaced by the new blood.

'Grading is principally used by cattle, poultry, and other breeders who have inferior stock and desire to raise the quality of this stock with the smallest possible cash outlay. So, a brooder of cattle possessing animals of scrub or only fair quality will have his females serviced by a fine bull of some desired pure breed (paying only for service) and breed back the progeny to this or a similar bull again, and so on for two or three generations, by which time the average quality of the herd Is very definitely enhanced, and at small expense!

Reducing the risk
In my own experience, particularly with pigeons, I have usually found it advantageous when I have decided to make an outcross to bring in several new birds instead of only one, and for this reason:

Outcrossing is at best a risky business--not so risky when there is distant relationship-and it is always possible that the new bird or animal introduced may not 'nick' (as fanciers say) with any of the mates provided for him. Your chances of finding a 'nicker' are, of course, increased if you are able to make several outcross matings instead of only one. When you are able to assess the merits of the youngsters, you may then decide only to continue to work with one of the outcrosses used in the first breeding season, and its progeny, it having given you satisfaction and the others little or none.

I have referred to outcrossing as a risky business, but this risk can be reduced it the bird or animal comes from a stud, the members of which are distantly or closely related to one's own stud, but which have been reared in a different part of the country. It often occurs that this semioutcross proves most helpful, especially in promoting what is known as hybrid vigour, usually associated conversationally with the complete outcross. As an example of the good which can come from a semi-outcross I recall my own experience many years ago with light yellow budgerigars. Mr R J Watts, of Cambridge, had established a wonderful strain of these birds by judicious inbreeding. I purchased some from him, and so did the late Lady Bromley Wilson, of MiInthorpe, Westmorland. We both enjoyed much success. We both consistently inbred. Her light yellows were better than ours in some points; ours were better than hers in some other points. Lady Bromley Wilson died, and from her husband I purchased a number of the best birds in her stud. These were mated with our own light yellows, and the result was wonderful. Our progress with this variety of budgerigar was accelerated almost phenomenally.

A disastrous result

I also remember an outcrossing experience in our budgerigar aviaries, the result of which was tragic. We owned a rather good team of light greens, pleasing in all properties, though in my opinion requiring improvement in head. Another breeder who, by the way, was not in the least to blame for what happened, had a winning collection of light greens better than ours in head. His were quite unrelated to ours. So I decided to outcross to his family, but instead of carrying out the operation in the cautious and gradual way described above, I did it in a wholesale manner. In the second breeding season after I had bought these birds practically all the youngsters contained both our own blood and the blood of the outcross, and they were a bad lotl I had ruined our stud of light greens, and learned a lesson[ Although the pairs which I had mated in those two years were excellent in so far as appearance was concerned, there was such a clash in the latent properties carried down from ancestors that it was impossible correctly to blend the two strains.

Those who adhere to, the two- (or more) line method only make semi-outcrosses, as I show in Chapter VI, unless it should happen that the need does arise to bring in a distinct ouicross into one or other of the two or more lines. Above I used the expression 'hybrid vigour'. It is generally considered that when two unrelated animals are mated there is an increase in the constitutional strength of the offspring because of the unlikelihood of them both having the same physical defect, and, consequently, the vigour of one overcoming the weakness of the other. But this isby no means an Invariable rule.

U.S. Marines Enlist Pigeons to Battle Iraqi Gas
Mar 14 2003 10:04AM

CAMP INCHON, Kuwait (Reuters) - U.S. Marines going into battle in Iraq will have state-of-the-art equipment to warn them of chemical or biological attack -- but their first hint of danger may well come from a pigeon.
The distribution of dozens of the birds to Marine regiments in the Kuwaiti desert on Friday raised some laughter but also underlined how seriously the U.S. military is taking the threat of gas attack should it invade Iraq.

"They're an extra sensor," said Staff Sergeant Dan Wallace, who is responsible for all precautions against nuclear, chemical and biological attack in his regiment.

Pigeons are more sensitive to nerve and chemical agents than humans. Just as canaries once warned miners of the threat of explosive gas, the U.S. military thinks pigeons may once again prove to be the difference between life and death.

"I got sensors that cost $12,000 and birds that cost $60 each and I place just as much trust in the bird as the sensor. Anything mechanical can fail or give us wrong readings."

Each bird came with a cage and a supply of bird seed.

The marines admitted they had little idea how to care for the birds, but said they would be learning fast. "We were supposed to get chickens but they died before they got here," Wallace said.

It was not clear if U.S. army or British forces would also get pigeons, which have a long history of helping man in war.

In Greek and Roman times, pigeons brought news of victory and defeat from the battle front. In World Wars One and Two, they carried messages across enemy lines.

Some were even awarded medals for their exploits.


This time, their role will be different.

"The pigeons are good because a lethal dose for them will not kill us," said Chief Warrant Officer Robert Gabrych, who had placed his birds in a shady spot in this desert encampment. "Hopefully they'll give us an early warning."

The First Marine Regiment was given 40 birds. Each is to get a handler, probably a lance corporal, who will care for it and give it a name. Officers predict the birds will become mascots.

The United States says Iraq's Saddam Hussein is hiding weapons of mass destruction in defiance of U.N. resolutions and has vowed to disarm him, by force if necessary. Iraq denies the charge.

A U.S.-led coalition is deploying a 270,000-strong military force for a possible attack on Iraq. Ground troops are poised to cross into Iraq from Kuwait wearing heavy protective suits and boots. They must carry a gas mask in case of chemical attack.

Most soldiers have also been inoculated against anthrax and smallpox in case Saddam finds a way to attack them with the stocks of biological agents Washington says he still possesses.

Wallace, dubbed the Pigeon Master by his fellow marines, says the birds could be useful if Iraqi forces blow up oil wells or bombs damage petrochemical facilities as fumes and heavy smoke can confuse electronic sensors, causing false alarms.

The birds could also detect toxic gases should an industrial facility or water treatment plant be hit, releasing noxious chlorine clouds.

"Sometimes the best devices are low-tech. That bird is going to tell us a lot," Wallace predicted.

03/14/03 10:00 ET

Band of feathers: Pigeons at war
Persian Gulf troops get birds for warning of chemical attacks


WITH THE 1ST MARINE DIVISION, KUWAIT - The problems began in the headquarters tent when the eight pigeons arrived Friday afternoon.

Warrant Officer Jason Gere looked distastefully at the caged birds on the table in front of him. "What are we going to do with them when we get our amtracs?" he asked, referring to amphibian tractor vehicles.

"Put the pigeons on top of the vehicle," replied Lt. Col. John Mayer, commanding officer of the 1st Battalion of the 4th Regiment.

"Next to the gunner, sir?" Gere asked.

"Right," said Mayer.

Ah, the pigeons.

On Friday, hundreds of pigeons were distributed to Army and Marine regiments scattered in camps across Kuwait. The pigeons, which replace the chickens that died on the way to Kuwait, are part of the U.S. anti-nerve agent arsenal. Pigeons, like chickens, die twice as fast as humans when exposed to gas and nerve agents.

U.S. military units plan to head into combat - if President Bush gives the go-ahead for an invasion of Iraq - with the pigeons atop some lead vehicles, assuming they can survive the constant wind and blowing sand. The pigeons would be an early-warning system for soldiers and Marines if the Iraqi army lobbed nerve agents at them.

Much of Friday's debate in Mayer's unit centered on who would be responsible for the pigeons and where they would be placed on the vehicles. Then followed a debate on names. "Trigger," one Marine suggested.

"The lead pigeon should be named Cookie," another Marine said.

"Cookie?" asked Mayer, a tall, gung-ho commander, in disbelief. "You need a killer name for your pigeon. Something to strike terror in the heart of the enemy."

After several minutes of discussion, they agreed on names for three of the pigeons: Doc (as in Holliday), Jackball and Sarsaparilla. Mayer walked away, content to let the men name the pigeons what they would while he made sure his flak jacket was in top shape.

All seemed settled - the pigeon names had been picked and the Marines thought up a plan for their care - when crusty Sgt. Major John Hamby walked into the tent from the desert and spied the birds. "Is this dinner?" he asked. "Who's plucking?"

Staff writer Rex Bowman is embedded with the 1st Marine Division.