"Quaking" Quaker Parakeets!

[Dr.Geoff]

Hi Avian Friends,
Exotic bird breeding and developing new websites has kept me very busy recently - hence my failure to visit Board Board since 1/28/08! You might wish to visit our new Forest Park Aviaries site, and associated sites, at/via:
Home, etc., and let us share your views?
This is a late-night submission, so I must be brief:
Why do Quaker Parrots, really Quaker Parrots!, "quake", particularly when they are being handfed or parent-fed, in the approximate age range from say 2-8 weeks? I have some thoughts, but would appreciate yours fellow exotic bird lovers & breeders!
Thanks Bird Board!
Dr.Geoff - Columbia Station, Ohio.