Finch genetics - wild and aviculture

[Glenbary]

Lonchura and others have had a very interesting discussion about the numbers of finches needed to make up a viable breeding colony.

The topic of animal genetics is of much interest to me so I have started this new post.

My other BIG interest is in fish, fisheries and fishing. I have been involved in many Qld Government fish breeding and stocking programmes. Right now I am contributing to the captive breeding of Jungle Perch (at the Bribie Aquaculture Centre) - and in the development of stocking protocols for JP.

The first issue is that little is known of the (wild) population genetics of most of our native birds. This is not just about different colour forms but the total genetic make-up of a wild population like budgies, Gouldians, etc.etc. In fish the very first priority before captive breeding and wild stocking is to look very carefully at the total population genetics. Fish species can have differing colours (eg Yellowbelly) but there are lots of other differences, particularly geographical differences in a species population genetics - behaviour, temp tolerances, salinity preferences.
What about birds? Many of our native finches have wide geographical distributions and genetic mixing is expected to be limited in many cases. Hence birds like budgies and Gouldians across their range in Australia can be expected to be genetically different - genetic variability within a species.
This has implications for both aviculture and possible wild restocking programmes.
For example, I have a fairly big collection of Gouldians. These birds are of unknown geographic origin, they have been selectively bred and inbred for many years before I obtained them. They are "domesticated" for a range of characteristics (eg ability to adapt to captive breeding, quietness, colour intensity, size, and of course colours). These birds are now very different genetically to those in the wild - however they provide me with much enjoyment and the ability to understand a lot of Gouldian characteristics such a behaviour, nutrition, breeding and colour genetics. What about wild stocking? It would be RECKLESS to restock birds like my Gouldians back into the wild - even those that have "normal" colours. There are two main reasons for this. Firstly the birds have been domesticated for around 40 years and are no longer able to cope very well with wild conditions. Secondly and more importantly the birds are of unknown genetic makeup compared to those where stocking is proposed. In the unlikely case that breeding occurred between wild and domesticated/stocked birds, the genetic makeup of the wild population is altered, and the wild population could suffer adverse effects.

On the very good question about how many finches would make up a viable genetic captive population - the answer is not simple and probably unanswerable from a scientific viewpoint - given the past history in captivity of the birds in question, and their unknown genetic status. Have they been inbred a lot? Were original birds chosen from a limited geographical range? What types of selective breeding have been undertaken?
My suggestion is to limit both inbreeding, and cross breeding of birds from wide geographical areas, including subspecies. However we must realise selective breeding in aviculture has its place and purpose but is not akin to what happens under natural selection in the wild.

[Diane]

I take your point and bow to your experience in both breeding the gouldians and fish and the knowledge and interest you have regarding these genetic issues.
However I do have a genuine question or two.

Given that you say

Firstly the birds have been domesticated for around 40 years and are no longer able to cope very well with wild conditions. Secondly and more importantly the birds are of unknown genetic makeup compared to those where stocking is proposed.

While I totally agree that it would be reckless to return birds to the wild that had been unused to those conditions, it sparked some thoughts.
Are we as bird keepers who are interested in preserving different species going to be limited to preserving them for the aviary only? As the genetic makeup of aviary birds is so different to the wild population are we chasing rainbows to try and preserve any species with the intention of returning the wild population to a positive situation that are struggling at the moment? The mere fact of breeders choosing the pairing of birds in an effort to continue the species is going to change the genetic makeup, so really we would be destroying that which we seek to keep safe.

[Glenbary]

Many thanks for the questions.
If a finch population is in trouble in the wild, the best approach is to determine the threatening processes and manage them with the aim of improving the wild population. Sarah Pryke and her team at Macquarie University have been doing this with Gouldians - managing hot fires/grazing practices, providing artificial nest boxes which are a limiting factor in the wild. Putting (stocking) domesticated birds of unknown (population) genetics into an already stressed wild population, would be in my opinion "reckless", primarily because of the potential impacts on the genetics of the wild population.
An exception might be where the bird is locally extinct such as was the case with Gouldians on the Atherton Tableland (Mareeba) in Qld - however uncertainties remain, especially if the stocked population was able to interbreed/intermix with a nearby wild population.

The scientific techniques for determining differences in the genetics of a wild animal population are now very well advanced. What is needed are tissue samples from the species across the geographical range of the wild population - then genetic (DNA) screening techniques in specialist labs to determine possible genetic differences. Following this, it is possible but not essential determine some of the key-factors that are inherited (eg. differences in behaviour, physiology, immunity, morphology, etc.).

In Australia this is now a standard procedure in fish stocking projects. Stocking of fish like barramundi, yellowbelly, jungle perch is done according to protocols to ensure that the genetic profiles of a species on a geographic basis are not compromised.

I appreciate the good intentions that many people have in terms of the conservation of our native bird fauna. When I (then Director, Qld Gov Fisheries Branch)first raised the issue of protocols for fish stocking with the recreational fishing community (eg. Freshwater Fishing and Stocking Association of Qld), I copped lots of flak. However now that they understand the issues, they are very strong supporters of stocking protocols. I believe this discussion and understanding is needed in the finch aviculture community.

Barry

[finchbreeder]

Particularly in view of the embarassing case of an endangered native mamal that existed in 3 locations. Stock was taken from the largest group and added to the smallest group, with nothing but a genetic record kept/cursory check. Yes the population increased. But the later check confirmed that the increase was allmost all from breeding between the mamals bought in. ????
Further checking revealed that the subspecies could not interbreed due to the biggest difference between them.
LML

[VR1Ton]

An exception might be where the bird is locally extinct such as was the case with Gouldians on the Atherton Tableland (Mareeba) in Qld - however uncertainties remain, especially if the stocked population was able to interbreed/intermix with a nearby wild population.

I beleive the best option in these cases would be restocking with captive breed wild stock, not aviary breed stock, as the chance of survival & re-population would be greatly enhanced, due to the inherant survival skills still remaining ingrained more so than aviary breed stock, selectively breed for many generations. But thats a hole new can of worms to open up.

[GregH]

I too can see both side of the argument. I’d like to think that by keeping birds I can contribute to the conservation of genetic diversity even if those birds aren’t used directly or presently for stocking in the wild. Arguments about genetic pollution are valid across the geographic range of a species however they are also distributed through time. It’s a moot point if the species in question has already disappeared from a site – there is no indigenous population to pollute. In isolated populations they just don’t carry enough diversity to allow them to cope if the ecosystem changes for whatever reason. I’ve recently seen results from an experiment at the International Rice Research Institute where they compared the yield potential of miracle rice varieties from the 1960’s Green Revolution to what can be grown now using the same seed at the same sites using the same cultural techniques. The results are around 20% less that the yields from 50 years ago. The conclusion drawn from this is that climate change and adaptation of pests and diseases over that time period has rendered formerly adapted varieties much less fit than the modern varieties. For field crops maintenance breeding is required to keep up with a constantly changing environment. If a species is to survive it has to generate diversity through the creation of novel genes or gene combinations. Novel genes created de novo (via mutation) are largely non adaptive or immediately fatal. It takes so long to generate the right mutation small populations are vulnerable to extinction waiting for an adapted genotype to evolve. The most likely source of new genes in breeding programs comes from integration of genes from other populations. Why can’t this be done in the wild? If Gouldians are no longer in North Queensland there is no population to pollute and obviously what was there wasn’t adapted to the ecosystem that exist there now, so why should there be objections to repopulate the region. Same might be said about the southern Star finch. Establishing a viable population in the wild is not easy but it can be done or we wouldn’t have things like Norfork Is Wood hens, Hawaiian Geese or all the ferals living free around the world. It’s sad that our planet’s ecosystems need this sort of micromanagement but one species is so out of control that it’s greedily appropriated half of planetary productivity for itself and altered natural ecosystems beyond the elastic limits of background adaptive process. I say background rather than natural because although extinction is as natural as the generation of new species we as a species now operate on the same scale as asteroid impacts and X-ray bursts. So without showing anymore of my antisocial tendencies where does this leave my wildlife management plan? I say if a contemporary yellowbelly from Roma has traits that are better adapted to the Darling at Menindee or indeed than the present Menindee genotypes then let it integrate or supplant before both population become extinct. I must be feeling depressed tonight as it doesn't look too rosy for present diversity without intervention while humans have the impact they do at present.

[Diane]

It’s sad that our planet’s ecosystems need this sort of micromanagement but one species is so out of control that it’s greedily appropriated half of planetary productivity for itself and altered natural ecosystems beyond the elastic limits of background adaptive process. I say background rather than natural because although extinction is as natural as the generation of new species we as a species now operate on the same scale as asteroid impacts and X-ray bursts.

I think its a case of "we are dammed if we do and dammed if we dont"

[Tintola]

[quote="GregH"]. Establishing a viable population in the wild is not easy but it can be done or we wouldn’t have things like Norfork Is Wood hens, Hawaiian Geese or all the ferals living free around the world.

Totally agree with everything that Greg stated. Don't mean to be pedantic but they are actually "Lord Howe Is Wood hens."

You're right - how about we put kikari's back there then to make up for it! GregH

[Glenbary]

In my earlier post I referred to the restocking of large areas where a species was locally extinct - as a reasonable thing to consider. eg Gouldians on the Atherton Tableland
However I maintain that it is reckless to stock an area where a population is endangered if the introductions could adversely impact (genetically) on the wild population.

The problem is that there has been little if any science done on the geographical genetic diversity of any of our native finch species. For example we do not know how different the Gouldian populations in WA, (eg. Kimberleys) are to those in NT or Qld (eg. Mt Isa) - or the adaptive values of such genetic diversity.

Perhaps we should be encouraging scientists to get active on finch population genetics.

Many thanks to those who are providing ideas on this discussion.

[Dmitroid]

It’s sad that our planet’s ecosystems need this sort of micromanagement but one species is so out of control that it’s greedily appropriated half of planetary productivity for itself and altered natural ecosystems beyond the elastic limits of background adaptive process. I say background rather than natural because although extinction is as natural as the generation of new species we as a species now operate on the same scale as asteroid impacts and X-ray bursts. So without showing anymore of my antisocial tendencies....

Haha GregH you sound like a kindred spirit! I was such a people person when I was younger but I find as I grow older, the inability of most to conceptualise this sort of conversation has become completely intolerable, and I find myself spending more and more time in my books, with my amazing partner (there are actually more of us out there) and with my animals... I would most certainly be the victim of regicide should I ever become king of the world.

It is a shame that our species urge to reproduce, and the vehemence of which we defend that 'right' seems to be stronger than our ability to rationalise sensibility, as we consume our planet from the inside out.

Dmitri