[Desertbirder]

Attached is a paper and images of one of the most amazing things I have ever encountered, I will be happy to get ( serious ) comments...
Jonathan

[SimonC]

Amazing! A very similar thing occurs in butterflies (but i can't remember the name for it at the moment!) I'm not suggesting this is the same thing, but it's a puzzler isn't it!?

[Klant]

Cool! And weird...

[tom mckinney]

I think it's called gynandromorphism???

I remember seeing an illustration in British Birds, from the late 1980s, that showed a House Sparrow with 50/50 features of male and female split perfectly down the middle.

I'll try and find it...

[SimonC]

Originally Posted by tom mckinney

I think it's called gynandromorphism???...

That'll be the word I was grasping for then..........or something like it at least.

[hannu]

Gy`nan`dro`mor´phism (jĭ`năn`drô`môr´fĭz'm)
n. 1. (Zool.) An abnormal condition of certain animals, in which one side has the external characters of the male, and the other those of the female.

[tom mckinney]

... it's in British Birds vol.85 p.675-676

Apparently such birds "have both an ovary and a testis."

Weird!

[Runcorn Birder]

Does that mean that this bird is a hermaphrodite then ?

It'll be a late entrant into Big Brother at this rate along with the rest of the freaks and mis-shapes.

And... has it had a rib removed so it can perform you know what ?

[KnockerNorton]

Well, you can also induce this effect in first year birds artificially. If you got a juvenile/1st winter male redstart, and plucked one side of its head, it would regrow just like this.

Sounds like a pointless thing to do, but it's been done.

[blgp_birder]

what a disgusting-looking bird.

[rupicola]

this amazing phenomenon is called Gynandromorph (Halfsider) and is in fact the result of the elimination of one X-chromosome during meisosis, causing an animal with one side of the body genetically male and the other side female. The presence of an Y-chromosome is not necessary for developing a female individual in birds and the Y-chromosome is considered to be non-encoding DNA for no genes have ever been found on it.

Gynandromorphism is not common but found in several different species.

I have seen halfsiders (in captivity) in Zebrafinch (Taeniopygia guttata), Barred Parakeet (Bolborhynchus lineola) and Budgerigar (Melopsittacus undulatus)
I was told breeding with a Halfsider Bugerigar resulted in healthy offspring! (no halfsiders) so these birds amazingly appear to be prolific!

[me1000]

Runcorn Birder
me

[TWM]

Originally Posted by rupicola

this amazing phenomenon is called Gynandromorph (Halfsider) and is in fact the result of the elimination of one X-chromosome during meisosis, causing an animal with one side of the body genetically male and the other side female. The presence of an Y-chromosome is not necessary for developing a female individual in birds and the Y-chromosome is considered to be non-encoding DNA for no genes have ever been found on it.

Gynandromorphism is not common but found in several different species.

I have seen halfsiders (in captivity) in Zebrafinch (Taeniopygia guttata), Barred Parakeet (Bolborhynchus lineola) and Budgerigar (Melopsittacus undulatus)
I was told breeding with a Halfsider Bugerigar resulted in healthy offspring! (no halfsiders) so these birds amazingly appear to be prolific!

Now that's what I call a reply! 10 out of 10.

[Desertbirder]

Thanks for the replies.
What are the odds ? 2-3 weeks of ringing in a very small area ( an incredible migrant magnet, but still tiny ) and we were lucky enough to catch one of these...
I didn't realize just how rare this phenomenon is.
I now wonder, has anyone actually ringed any wild birds showing Gynandromorphism or actually seen Gynandromorphic (?) birds in the field ?? Redstarts in particular ? I know In southern Israel during spring there are days with dozens of Redstarts going through, I 'll be paying extra attention to every Redstart I see from now on...
Thanks again for the detailed replies.

[CJW]

Originally Posted by blgp_birder

what a disgusting-looking bird.

What a completely inane and stupid comment.

[redeyedvideo]

Does anyone know how I can open this Windows file in a Mac? I can read the script but can't see the pic.

Thanks in anticipation.

Dave J

[Desertbirder]

Hi, I cant help you there,
but you can find the whole piece on www.birdingisrael.com

[redeyedvideo]

Originally Posted by Desertbirder

Hi, I cant help you there,
but you can find the whole piece on www.birdingisrael.com

Many thanks, it was good to read the other reports in particular the lutea Yellow Wagtail which has been reported in the UK but usually dismissed as
M.flava flavissima although they look identical to the pictures on the site.

Dave J