I have 7 cockatiels, 4 male and 3 female. All four males display as you would expect. 3 of the males display in the usual way by hang sideways on the perch horizontally and spreading their wings and tail. The 4th, Custard, does the same, except he hangs completely upside down.

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Not everything that goes up comes back down. Your age for example.
My pets (sorry I can't upload any pics yet)
Cats
Candy (12) Neo and Simba (10) Del Boy (7))
Cockatiels
Undertaker (My OH's choice)(10) Souxsie(10) Sid(9) Rimmer and LIster(1) Ruhbarb and Custard(hatched july 2010)
Rats
Frosty and Jack(1)
Gerbil
Pepper(almost6) Pepper sadly no longer with us RIP pepper.
Its almost a zoo at home,but we love them all.