Tell tale sign.

[Redballoon]

[ame="http://www.youtube.com/watch?v=S4dpfLweoRk&NR=1"]http://www.youtube.com/watch?v=S4dpfLweoRk&NR=1[/ame]
The clip above does nothing for me really, but its a very good chance to make yourself look clever.
The two birds in the clip can be sexed by looking into their eyes.
She has a small black pupil, surrounded by a lighter iris, and He has an all black pupil.
Next time your at the pet shop you can now show off when you see a Galah in a cage.

 

[TexDot33]

I always thought that this was for all 'toos. I also thought that female's had like deep ruby colored irises ... maybe Zarifia can shed some like on this for us. She is our resident 'Too expert.

 

[kim]

I'm pretty sure only galahs have those eye colours to tell the sex, not all cockatoos. The rest of them all have equally dark brown eyes. At least all the corellas do anyway.