Introduction

The mere mention of the word "hybridization" tends to elicit a very negative reaction from many breeders and hobbyists.  Consequently, some breeders view the word "transmutation" (usually referencing the transmission of a color mutant gene from one species to another) as a more palatable alternative.  This semantic change could be deemed analogous to the response of people to "inbreeding" and the adoption of the term "closed flock".  Regardless of the definition, for many people hybridization is bad; end of story.  For those people there is little point in encouraging or discussing something that "pollutes" the gene pool of a desirable (pure) species or results in a nest full of offspring that can vary significantly in physical appearance and genetic composition.

I thought hybridization was worth a little effort, on my part, to determine the role hybridizing has played in various bird species.  The results of my reading were quite interesting.  Hybridization seems to be a matter of magnitude and definition, but in the end the objective is to generate a new line, variety or breed of bird that excels in some feature or features (traits) that makes it economically valuable or aesthetically pleasing.  That value may be based on a variety of expectations, such as: homing instinct and speed; size and color; egg production; meat production, and adaptability to or survivability in harsh climates.

The application of hybridization in animals (dairy; beef; poultry; sheep; goats, etc...) and in plants is well documented in history and has generated a tremendous volume of anecdotal information, scientific reports and myths.  The peachfaced lovebird is only one of a few "domestic / captive" bird species (primarily psittacines ?) that have not been subject to intense efforts to develop new breeds or strains.  Ridiculous ?  Look at the canary and the efforts that went into developing new varieties (lines / strains / breeds), some for song, some for looks and some... because people could.

As far as I am aware, mutant color gene transference (transmutation) has occurred only among the eye-ring species. That process can take anywhere from three to ten years (some suggest that statistically it might only take 4 generations to get pure birds) to set the color, morphology, and behaviors of the recipient bird species in the hybrid.  If one is going to pursue this avenue, a substantive quantity and quality of wild type birds should be available to ensure that the best hybrids are mated back to the best (standard) of the recipient species:  size, color and physical structure are very important at this juncture. At the end of the road, and under a practiced hand, the hybrid will come to resemble the recipient species in all but color.  The hybrid, no matter how good it looks or how closely it resembles the color recipient species, may sometimes produce an offspring (throwback) that looks more like the progenitor species.  This is particularly true if pet owners breed "new color variety" birds to each other.  The "throwback" is simply the penetrance and expression of the heterogeneity (sometimes hidden) of the crossbred.

Successful hybrid color penetrance and acceptability is based on the hybrid bird's genome comprising a greater percentage of the recipient species genome and only a relatively small percentage of the donor species genes.  The color impact is easily assessed, but the impact of associated genes are neither well known nor well documented.  It is not possible as yet, as far as I am aware, to extricate or isolate the complete chromosomal segment (associated genes and loci) transferred with the new hybrid color gene after hybridization has occurred.  It is because of these associated genes and the apparent inability to remove them from the hybrid genome, that people believe there is no reversal in the hybridization process, and that the potential for pet owners to breed these birds indiscriminately with "pure" species is high.  The result of this indiscriminate breeding is that the pure gene pool becomes rapidly "contaminated" by the "hybrid gene" presence, and progeny are produced with indistinct or blurred coloring.

The offspring, except for a rare occasion, would probably not be shown or exhibited at competitive events because of the demand for clarity and intensity of color; sharp delineation between colors; size and an unspoken expectation that the bird will be able to pass on certain "pure" and "desirable" traits.  So, what do you do with these poor representatives (hybrid) of the species ?  It is important to remember that for every successful hybrid, there is a long trail of birds that did not make the grade.  However, this is true in almost every captive species, whether they be chickens; pigeons; budgerigars; turkeys; canaries or finches. What separates the Lovebird ?

The following points are meant to get people thinking about species and hybridization concepts and the implications or trickle down from hybrids:
 

•  A hybrid may be defined as the offspring from two different varieties, breeds, genera or species.

• Hybridization, in essence, is the crossing of birds or animals that may or may not differ markedly in general physical appearance, and may or may not have significant differences in their genome (this may be only one chromosome that has been subject to a physical alteration, or a substantive change in the genome brought about through selective breeding, or natural events)

• Reasons often cited for speciation in the wild are: isolation, physical limitations, out-of-sync reproductive cycles, incompatible chromosomes; inability to communicate (sound), food niche and selection, migration patterns, colors and social behavior.  I am sure there are many more

• The white eye-ring lovebird species intermingle/ hybridize without difficulty and, as I understand it, both male and female offspring are quite fertile in captivity. The eye-rings are classed as a different species from the peachface, and each eye-ring species has a "clear geographic range".  There are reports of hybridization among eye-ring species in the wild, where flocks overlap, but I have not heard of any fertility data that was collected, or that could identify varying fertility percentages and mating choices in hybrid progeny.

• Speciation in the wild can occur through the gradual or rapid development of a variant (s) (either within a species or the result of two similar species interbreeding) that, after a period of time, loses the ability to exchange genes (sterile offspring or none) with the founding wild flock.  This might be due to a chromosomal aberration or alteration in the variant; a different reproductive cycle; lethal genes or a host of other potentials.  As well, a catastrophic incident can lead to isolation of a species and subsequent slow alterations in form or genome.

• There is an "understanding" among lovebird enthusiasts that a peachfaced crossed with an eye-ring species will result in a sterile hybrid.  Others have observed that the progeny of such a mating may act differently in regards to social and nest building behavior. Conversely, there are those who hold to the notion that peachfaced x  eye-ring crosses are fertile  This belief or sentiment continues today, but more people seem to be asking about it (perhaps it is just the Internet?)

• As early as 1930, people were indicating that at least some peachface / eye-ring crosses were fertile.  It is also well known that a certain percentage of hybrids or "crosses" will be fertile, although fertility may drop off significantly when mating hybrids together versus crossing the 1st generation back into one or other of the parental lines.

Can anyone who has kept and bred the progeny of a hybrid Peachface / Fischer or Peachface / Nyasa or other combination mating, for longer than 5 years, shed some light on this topic, and let us know if the offspring (male or female) produced young ?

Can hybridization slow or alter the development of the reproductive system, and if so, which sex is most likely to be impacted ?

• Finally,  don't believe everything you read or what someone says.  Always question what you are reading and hearing and determine your position based on the evidence and  your own research.  Nobody has all of the information, but the African Lovebird Society (ALBS) is probably the most in-tune and long term over-seer and manager of lovebird information and knowledge that I am aware of.  Write to them, ask them what they think.  Don't dismiss this site or this document based on prejudice against hybridization or because someone has told you peachface hybridization is not possible.  Question the facts and the theory, but not the possibility.  Let me know what they say, and I will correct this page if proven incorrect.  If an experienced breeder can provide information for or against the low probability of  fertile peachfaced hybrids, I will post that as well.  Otherwise, please read the following and prepare a cogent argument against fertile peachfaced hybrids, if you do not ascribe to what is said.  It will be posted.

• The Peachface lovebird is intermediate between the three lovebirds known as: Abyssinian, Madagascar and Red-faced, and the eye-ring species (Fischer; Masked; Black-Cheeked, and Nyasa

• The Peachface has successfully produced at least some Hybrid offspring that were fertile from the following crosses:

 

"SPECIES" A	BY	"SPECIES" B
Nyasa	X	Peachface
Peachface	X	Nyasa
Black cheeked	X	Peachface
Peachface	X	Black cheeked
Peachface	X	Fischer
Fischer	X	Black cheeked
Peachface	X	Masked
Masked	X	Peachface

• There are also "rumors" that suggest that the Peachface has produced Hybrid offspring from the following crosses:

 

"SPECIES" A	BY	"SPECIES" B
Madagascar	X	Peachface
Peachface	X	Madagascar
Abyssinian	X	Peachface
Peachface	X	Abyssinian

• Where is the data that states that roseicollis offspring are infertile or mules.  Surely, a bird that is an intermediate step in the lovebird family has the affinity and potential to produce fertile offspring with closely related birds.  We know that all lovebirds are essentially seed eaters and that the functional organs, both internal and external, are established to deal with seeds, and not insects; that their morphology is relatively similar, despite known behavioral distinctiveness, and that they are related taxonomically.  Why wouldn't they be fertile ?  The maturation period for full fertility may differ substantively from the "normal expectation", but fertility potential may exist none-the-less.

• Is it a wise "policy" to remain silent when errors may exist with regard to the viability of offspring arising from interbreeding of the peachface and other lovebird "species".   Statements such as: "peachface offspring, from an inter-specific cross" are all infertile and mules, a "species" cannot cross with another "species" and generate fertile offspring".  It is particularly striking when dogmatic statements of this type are made by "learned" individuals, particularly when the statement flies in the face of well documented proof of fertile offspring between eye-ring "species".  No one comments on this over-sight though.

• Someone who mates their birds indiscriminately and gives them away or sells them as something special, is usually passing them into the hands of a "novice" (usually).  If that novice receives them in their second or third year and the birds produce offspring, or are mated with aviary birds, who is to tell the novice that they  have polluted their "gene" pool and stand a good chance of polluting more if they sell those birds as pure "lovebirds"?

• The effort to make people believe that peachface hybrids are infertile, if indeed this is not so, can potentially lead to greater (and innocent) degradation or pollution of the population and "gene pool", than recognizing and trying to inform people about hybrid breeding impacts and the need for having them classified and identified for what they are.  That knowledge and acceptance is only gained by educating people and providing examples and descriptions of possible offspring phenotypes and their consequences, not by trying to prevent the production of them, but perhaps by requiring that hybrids be ringed in a particular color or with a definable inscription.

• If, as so many seem to believe, hybrid peachface offspring are "sterile or mules", the question automatically arises as to how a mule or sterile bird might pollute a gene pool or threaten a species ???   The obvious rejoinder is that a percentage of hybrids may be fertile.

• If you doubt or question the information provided, GOOD, I have done my job.  Please do some of your own research on lovebirds and then question the reliability and validity of information placed here, in order that you might derive a better understanding of lovebird behavior and potentials.

• Lest people think definitions surrounding inter specific breeding and "species" are fixed, immutable or infallible, please look at the following sites, that provide a little insight into the level of academic discourse and peer review that still revolves around "classification" / "taxonomy" and "speciation" / "hybridization" (pro and con):

• Sibley and Monroe Classification System

• Sibley Overview

• Critique / Criticism of Sibley and Monroe Classification Process

• Hybrid relations and fertility impacts

• Birding list

• A table containing lovebird F₁  hybrid fertility based on Sibley and Monroe Dna/Dna Analysis ( I cannot, now, find the organization responsible for this table.  If an intrepid web searcher can find the sight and relate it to me, I will attach the document (excel spreadsheet)... my sincere apologies to the authors, and others. I hope that the document can be located and attributed quickly)

• People seem relatively comfortable with terms like: line, strain, variety and breed.  I must admit that they still have a tendency to confuse me, as everything is relative.  A fixed strain or breed may be the result of 10 to 20 generations of intensive culling, selection and family breeding.  The process identifies and attempts to remove many of the more "undesirable traits" so that a relatively homozygous line of birds is created.  Their genome would eventually be quite (perhaps significantly ?) different to the heterozygous pet shop or wild type bird.  Crossing "line" birds with a wild type (diallel cross or outcross) may result in the benefits of heterosis and decent looking birds in the F₁, but a fertile mating between the F₂ could generate hybrid offspring with significant phenotypic and genotypic variation

• What do you call highly selected birds ?  A strain ?  A breed ?  A race ?  A line ?  A variety ?

• How different might a "line's" genome (14 generations) be from the wild type bird, and how might it compare to the average  numerical distinction (% difference) between the genome of  similar species ?

•  A prepotent cock (or hen) in a line or strain of birds carrying homozygous factors for a number of desirable (selected) characteristics can pass on his genome with great penetrance and expression in the progeny, even if the hen is only average for a few traits.  The progeny or first filial generation F₁ would be very similar in appearance to the cock bird, but the problem occurs when the F₂ or second filial generation is crossed among itself.  In this instance a number of hybrid or undesirable offspring may be generated

• Two highly inbred lines of birds may be developed from several pairs of progenitor parents.  Aggressive inbreeding would lead to birds with a highly select genome, and one that might not occur naturally, or not for a very long time.  The progeny resulting from a crossing of two such inbred lines (where the intent was to generate a third line) would be referred to as a recombinant inbred line and again, the F₁ cross would appear very good phenotypically, despite being heterozygous for different traits.  The F₁ is a hybrid cross: the F₂ is also a hybrid cross (mono and di-hybrid crosses) but would have greater variety in phenotypes and genotypes

•  Wild flocks can overlap and "species" can and do interbreed to produce offspring (thus a natural event or occurrence)

•  In nature, the development of a new species might occur through gradual pressure and selection or isolation or conversely very rapidly ( physical chromosomal alteration)

•  In selective breeding activities the genome can be filtered relatively quickly with an aggressive methodology and a close breeding plan

•  A selected strain, line or variety of lovebird, at some point, can become quite genotypically different from the "parent population"

•  The point at which the genome needs to differ enough to generate a "hybrid" when crossed back into the "wild population" is unclear (depends on number of generations, number of out-crosses if any, selection pressure and how different the selected traits are from the norm ?)

•  In the dog, chicken, canary, cat and other species, a number of breeds have been generated (isolated) through selection.  New breeds are generated by crossing (hybridizing) these existing breeds and selecting desired traits from the F₁ or more infrequently the F₂.  Through further selection a new breed is then developed.

•  Breeds / strains can and do disappear without continued work and maintenance by people.

•  Hybridization in the lovebird community has been used for color trait transmittal (transmutation).

•  Selection within a species can help to generate and identify color mutants, lethal genes, autosomal recessives, structural inheritance and their correlation with other traits.

•  Hybrids can result within a species, without the necessity for breeding with another species.

•  Hybrid production may result in the start of a new strain, just as identification of a desirable sport and selective breeding to enhance one of its attributes can

•  If color mutants were not maintained by breeders or desired by the public, they too would soon disappear as they are recessive to the wild type bird

• The 1st generation will exhibit some variation among themselves and consequently, birds are selected for their appearance and bred together in an  effort to establish a new line.  The 1st generation in this case would need to be similar in form and color for the trait being sought by the breeder.  After that it is a matter of selective breeding to build up the line.

• Sometimes a line or strain of birds may experience a reduction in size, loss of vitality or a failing in one of the desired traits.  In this case, the breeder will often go outside the line to breed in a bird of a known pedigree, that is high in the trait desired.  The breeder may also look for a bird that has no pedigree but is also strong in the trait desired.  However, this may inadvertently lead to a re-introduction of genes that had previously been extracted from the line or strain.  The conscientious breeder will pair the "out-cross" with a bird of their own line and hope for a strong showing of young with the desired trait.  Heterosis should provide the desired increase in fertility and vigor.  Having identified the 1st generation stock with the desired shape and size, the breeder would pair the second generation birds back to other birds of their line, in a quarantined area, to ensure that undesirable autosomal recessives or other hidden problems are identified / caught, before introducing the new birds, now strong in desired trait and form, to others of his flock.

• Conversely, an individual may want to base their success or championship lines on birds that have won on a regular basis.  From this approach the expected outcome is that hen and cock champions will breed a line of winning progeny.  This may or may not be the case, as the winners may be sports (one-offs) without the homozygous potential to reliably pass on their gene composition.  The hen too may be a rather good bird, but lack the prepotency to pass on her characteristics.  The offspring in this case may be heterozygous for a number of traits and none may display the desired characteristics.

 
As long as there is a market for birds with a different appearance and form, people will continue to hybridize their birds in the hope of having something special to market.  People look for the rare or different in many of the things that they seek.  Different colored birds are some of those rare and wonderful things.  If you have ever been to a bird show and seen the wonderful species, variation and color of the birds present, it would not take long to start thinking how a bird might look really eye-catching if it had blue wings, a red head or was bigger or smaller.  Recent shows on the continent have revealed the presence of a relatively new "variant" of peachfaced lovebird in the Standard type roseicollis (Longfeather in the U.S.).  As well, a recent color mutant gene in the Lutino variety, named "opaline" (Rose-headed) has led to a bird with vivid color and solid head color.

One thing we know is that change is the common denominator and that it will continue, whether it is through a mutation or "transmutation".  The number of birds being bred and the efforts of a few dedicated enthusiasts ensure this.  The feather impact in the chicken, canary and budgerigar world is well known, and it is probably only a matter of time until we start to see feather specialties (crests) occur in lovebirds. What do you think ?