Aussie Finch Forum

Uraeginthus wrote:de Ross book: black belly

De Ross book - male. A black area with sooty blending into brown which is slightly darker than the back colour - not paler. The photo quality in this book is a bit ancient too - on the same page the cock Melba's face is pink & the male OB's back is black. Perhaps Russell Kingston's earliest book is a more accurate indicator with likely better photo quality.
As with the original youtube video posted by Gary the differences between the black-bellied & brown bellied birds in the same batch are males & females.
I've never seen a male BH Nun without some black on the belly. The keys are how gradually it blends to the surrounding brown, the relative intensity of that brown & whether the black exists on females.

So does that mean that Gary's original 4 birds are all hens as they all have brown bellies ?

I'd be very surprised if the males don't have at least some black low down on the belly. If they are atricapilla or sinensis this would blend gradually into the brown & any brown on the belly would be very dark.

Thanks Tiaris,

I never really appreciated this sexual dimorphism in BH nuns previously.
I guess it makes it very difficult when you are dealing with birds of different origins, complicated by the possibility of hybridisation.

I have sent an email to Robin Restall who wrote the book on Munias.
Robin has retired to Venezuala and if he is well enough he may assist us.
It is quite some time since we last made contact but if anyone knows he will.
Personally i have always presumed that Male and Females were the same feather colour wise
You never stop learning do you.
E Orix

Myzomela wrote:So does that mean that Gary's original 4 birds are all hens as they all have brown bellies ?

I always presumed that by definition all nuns were hens and I've never been intimate enough with one to observe the belly colour. Generally the belly is well hidden - I never suspected a brown belly could be lurking beneath the garb! Totally agree with EOrix - you never stop learning.

E Orix wrote:Personally i have always presumed that Male and Females were the same feather colour wise
E Orix

They often are. We should remember that subtle differences in appearance that we percieve as subtle dimorphism can be easily enhanced under selective pressure depending on the perception of the breeder. In this case if we percieve that males should have darker bellies and females lighter and we breed with this in mind we can selectively create a population in which that is the case. In the reverse, if we selectively choose to breed with males that have barely perceptable black to hens with no black then we can produce populations in which that feature is absent.
In my teens I was able to selectively breed masks and longtails to be sexable at fledging - hen masks with tiny face markings were mated to cocks with huge masks. Over 2-3 years I created a line that fledged small faced hens and large faced cocks. With longtails I selected hen with bibs that were tiny and mated to cocks with massive bibs with the same selective result.
These same selective pressures(e.g. mate choice, environmental advantage, predation preferences) are what create differences in subpopulations of wild birds in the first place, only in the wild it occurs randomly in a large populations whereas in captivity we accelerate it with discreet pairings in small populations.
Nothing is ever clear cut in populations of animals.

We always sexed our BH Nuns very reliably by the blacker belly on cocks and the more straw-coloured yellowish top of the tail on hens. As with any monomorphic species the differences can at times be insignificant.
There are undoubtedly some subspecies of BHs with quite pronounced black bellies compared to others but these were not a noticeable part of the Australian aviary population that I ever saw in decades past. Just a more regular recent occurence in our stocks which are comprising an increasing proportion of BH stocks as time goes on which further indicates to me the likelihood of Tri-coloured genes as BH Nuns have become less common recently.
Its interesting to also note that Restall's monograph illustrates and makes reference to "cinnamon" flanked forms as seen in North-eastern India as geographic variations of the Tri-coloured. The likelihood of this form originating from an integration of BH genes is very high given the proximities of their natural ranges there.

Danny wrote:

E Orix wrote:Personally i have always presumed that Male and Females were the same feather colour wise
E Orix

They often are. We should remember that subtle differences in appearance that we percieve as subtle dimorphism can be easily enhanced under selective pressure depending on the perception of the breeder. In this case if we percieve that males should have darker bellies and females lighter and we breed with this in mind we can selectively create a population in which that is the case. In the reverse, if we selectively choose to breed with males that have barely perceptable black to hens with no black then we can produce populations in which that feature is absent.
In my teens I was able to selectively breed masks and longtails to be sexable at fledging - hen masks with tiny face markings were mated to cocks with huge masks. Over 2-3 years I created a line that fledged small faced hens and large faced cocks. With longtails I selected hen with bibs that were tiny and mated to cocks with massive bibs with the same selective result.
These same selective pressures(e.g. mate choice, environmental advantage, predation preferences) are what create differences in subpopulations of wild birds in the first place, only in the wild it occurs randomly in a large populations whereas in captivity we accelerate it with discreet pairings in small populations.
Nothing is ever clear cut in populations of animals.

Yes, Iused to breed Bourkes and became so familiar with my birds that I could pick the hens straight away. Over generations of keeping your best stock, I imagine some bloodlines would have subtle differences like that