Aussie Finch Forum

Hi guys
I've found a new interesting study about longtail populations. It makes a new point about yb and rb evolution, for those interested I suggest to scroll down and start reading from section "Discussion" downwards (unless you are a PhD in genetics).

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3402195/

ciao
Dimar

Interesting article. Thanks.
The idea if an intermediate form (orange-billed) being accepted as a third sub-species is far from new. Many have proposed this over a very long period of time.
I found it very interesting that a DNA test for genetic diversity is available. Given the number of samples in this study it mustn't be too expensive either. Would have very useful application in aviculture for monitoring declining species & flagging those which require attention.

Very true Tiaris.

It amazes me how researchers can access these resources, and yet those with a practical need for it-ie aviculture- usually cannot.
This is either because the service is available only on a research scale, not a commercial scale & is a branch of some greater research. The financial cost of providing the service on a commercial scale may be prohibitive.
Then again, that's how DNA sexing started-now look at it.

Thanks for posting Dimar.

I also have noticed that Hecks seem to be deeper in colour. Maybe that is just an artifact of us breeding for better colour.
Am I going mad ?

Uraeginthus wrote:I also have noticed that Hecks seem to be deeper in colour. Maybe that is just an artifact of us breeding for better colour.
Am I going mad ?

You maybe right Tom but i never bred Heck's for darker body colour but for deeper coloured red beaks,but in saying that their body colour,especially their backs are of a slightly darker colour compared to the yellow beaked variety. Cheers Craig

Well the whole article is quite difficult to understand, but if you read it carefully there's a new idea, opposite to the current thinking of orange billed being an intermediate form between yellow and red billed. The new idea is that in the beginning the longtail was rb, then ob developed from rb (due to ord arid intrusion), and eventually yb developed from ob. This new idea would be well supported by different levels of genetic pool diversity in the three forms. This is an excerpt:

(...)It is possible that individuals from our eastern and central regions are representative of two groups that were separated at one point in time by the Ord Arid Intrusion and that have not had sufficient time to become reciprocally monophyletic.The population in the western region may have been subsequently founded from a small number of individuals from the central region expanding the range westward when arid conditions abated. Levels of genetic diversity support this concept: samples from the western region had the lowest level of genetic diversity (Table 1; Fig. 3). The highest levels of genetic diversity were found within mtDNA from the eastern region, consistent with larger post-separation population sizes in this area. Additionally, the topology of the haplotype network (Fig. 3) supports this alternative explanation. Haplotypes found in the western region were mostly terminal, suggestive of a more recent origin whereas the most common haplotypes found in the central and eastern regions (A, H, L) appear to be ancestral as they located at the center of a star-shaped radiations typical of evolutionarily recent population expansion (Slatkin and Hudson 1991). Furthermore, only in the western region are haplotype proportions highly skewed toward a single haplotype (85%­of individuals carry haplotype R), which is indicative of a small founding population and subsequent genetic drift. (...)

Now this article is most recent, hopefully it will be cross-examined by other scientists in the next months or years, so we must wait and see if this new concept will take the current one's place.

ciao
Dimar

It seems to me that there may be three distinct and reasonably true breeding bird types. Those who cross the 2 extremes may not be simply producing the intermediate but may in fact be just producing something that looks like it - wild bird looking similar but being genetically distinct from the crosses in the aviary. Weird or what ?

Uraeginthus wrote:I also have noticed that Hecks seem to be deeper in colour. Maybe that is just an artifact of us breeding for better colour.
Am I going mad ?

No Tom, I noticed the same feature in legally wild-trapped red billed longtails (Hecks) that were part of a research project- I was struck by how much darker they were, as in the photos in very first finch book I bought as a child- "Finches" by DW Noreen? (paperback).
Imagine my disappointment when I saw my first yb longtails as a kid and the colours were so much lighter. I thought the book photograph was a printing error.
Then much later the darker colours on the rb longtails reminded me of what attracted me to this species all those years ago.

That was my first finch book too. I vividly recall the Heck's photo with the grey head/neck areas which looked positively blue & fawn backs which looked chocolate brown. This book also had a photo of a pair of Gouldians which was my first image of Gouldians - the cock looked brilliant but the hen was the most hideously terrible looking hen Gouldian I have ever seen.