New Sexing Method for Diamond Firetails

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dano_68
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New Sexing Method for Diamond Firetails
by Danny Searle

It is a well know fact that birds see in perfect colour vision. With this in mind I have often wondered why many finch species are “Monomorphic”.

Monomorphic refers to those species where the sexes appear identical. If they see in colour, why then would the cocks look like hens? I then remembered that many birds, like Budgerigars can also see in Ultraviolet. Ultraviolet is a wavelength too high for humans to see. Ultraviolet lights are sometimes referred to as “black lights”. They make white shirts and teeth glow, and hidden arm stamps in nightclubs to show up!

This got me thinking. What if monomorphic finches were actually viewing each other in ultraviolet? Having worked with computer graphics for years I was very comfortable with using graphics software programs like Adobe Photoshop.

Using Photoshop I imported some pictures of monomorphic finches and began to apply different filters to mimic ultraviolet light. The first species I toyed with was a known pair of Diamond Firetails. I wanted to use a picture of a known breeding pair to see if I could see any visual differences when subjected to the colour filters. It was when I viewed the image as a negative that something jumped out at me! I saw a difference in the sexes so obvious that I couldn’t believe it had never been picked up before.

Here is what I found. The Diamond cock bird has a break in his black chest band where it meets the wing. The hen on the other hand has a smooth line right down the side of her body. So in the male, it is like a semi-circle cut out leaving a white patch. See images below.
pair01_unmarked.jpg
pair01_marked.jpg
Here is what I believe is a hen and a cock bird:
Firetail_Diamond_cock_markedsm.jpg
Firetail_Diamond_hen_marked.jpg
Within a couple of days of this discovery I visited 2 well known breeders and put my method to the test using their Diamonds.

I got 6 out of 6 correct!

It is still too early to say whether this is an absolute method of sexing Diamonds, but it is certainly looking promising. Therefore I would like to conduct an experiment. Any aviculturists who have known breeding pairs of Diamonds go and check your birds and see if my method holds true. Next, show someone (who does not know the sexes of your birds) this article and see if they can correctly sex them using my method.

It would be great if you could then report your findings back to me. We could then tally the score and see if this new method works.

This new method could help fix an age old problem with accurately sexing Diamonds! I have been looking at as many Diamond pictures as I can find and believe I can now sex these birds as quickly and accurately as if I was looking at Zebra finches!

I hope this helps anyone who has found sexing these finches difficult. Who knows, with more tinkering with colour filters I may unlock some more mysteries!

Good Breeding!

Danny

Postscript
Since this article was published in September 2010, 27 Diamond breeders returned results to me.

The scores using my method were as follows:

Young birds not fully coloured into adult plumage = 94.7%
Adult birds = 85%
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spanna
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thats really interesting dano, will have to get out and have a look at mine tomorrow and see what I can discover! will be good as they are by far my most difficult bird to sex. will let you know of results too!
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Diane
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I mentioned this Ultra violet vision in connection with gouldians young recognizing their parents, and the choice of the partners head colour and the sex ratio of the resulting clutches in the forum in another topic.
I think its more than likely a highly relevant aspect of a birds life.

http://www.aussiefinchforum.net/viewtop ... let#p27761
Diane
The difference between Genius and Stupidity is, Genius has it’s limits
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flap
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I don't have any diamond firetails but wonder if the same principle would apply to Double Bars?
So I wonder what we would see if we went into the aviary in the evening with a black light??? Only problem with my master plan in terms of sexing DBs this way is that they roost at night...
flaP
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desertbirds
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Good work Dano.Just had a look at mine,fawn hens are obvious as is a split cock.The other cock is dubious and its interesting that only one pair has gone down.I cant say ive seen the other cock displaying either.May be time for a DNA test.How accurate is the DNA testing? I`ve recently had some Redbrows done and im dubious about a couple of birds.Some people swear by it and others say it can be a bit hit and miss.I`ve noticed with Redbrows that good photos show the brown tinge on the hens,this tinge can be hard to pick up in the aviary or a small holding cage.If you would like to play with some photos and see what comes up send me pm with an email adress and i will forward some shots.I would also love see some photos of more species taken under a black light.I think it would be really interesting to see what shows up.
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Diane
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flab wrote:So I wonder what we would see if we went into the aviary in the evening with a black light??? Only problem with my master plan in terms of sexing DBs this way is that they roost at night...
The only thing you could do would be set up the light near their roosting spot and turn it on just before they settle down for the night.
Diane
The difference between Genius and Stupidity is, Genius has it’s limits
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desertbirds
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Careful setting lights up if the birds arent accustomed to it.The light will attract insects (especially on warm humid nights),in turn attracting geckos,frogs and large spiders.The birds can also become a bit flighty,not being used to the extra light and activity.
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Diane
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I wasnt meaning for the light light to be a permanent feature, just a night or two for a little while while trying determine the sex. :D
Diane
The difference between Genius and Stupidity is, Genius has it’s limits
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Redwing
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Looking at the patterns is the 3rd bird on the left in the picture a male also?
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dano_68
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Redwing wrote:Looking at the patterns is the 3rd bird on the left in the picture a male also?
well spotted Red, and yes it is! (I was curious if anyone would notice that)
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