This is from a post, over on theperch.net
A couple days ago I was at our local avian vets office and I noticed a sick female Eclectus. The bird had totally stopped eating and the owner had brought the bird to Dr. B for treatment.
X-rays indicated severe blockage of the intestines and required surgery.
Dr. B performed surgery in an attempt to remove the foreign object/material and sadly the bird did not survive the operation because the material was far too deep inside the intestines. The blockage turned out to be cotton or cotton-like material from a sock. The owner had seen a suggestion on an online message board to fill a sock with nuts, treats, etc and then hang it in the cage like a toy. Dr. B. said that the bird must have ingested the material while trying to get to the nuts inside the sock.
Dr. B asked me to post this warning here on The Perch to try to get the word out that material ingested from a sock can be very deadly to birds and that socks should not be placed in a birds cage.