Here's a cockatoo with one on:
www.parrotchronicles.com/novdec2004/fitting_collar.jpg
( KersaI Missive Free Michael Shields! with Monday's Liverpool Echo, Wed 23 Jan 2008, 18:11, archived)

Rottern bastards
Funny though
(bogus official shove it up your cunt, Wed 23 Jan 2008, 18:13, archived)