Complete Dictionary of Dreams
by Dr. Mıchael LennoxThe cockatoo is less colorful than many of its brethren, so it relates to something more subdued, but still vibrant.
The traits that are most directly associated with this type of bird are a very strong beak and a loud, shrill voice. This adds the texture of harsh and strong communication to the symbolic meaning if this bird should appear in your dream.
(See Birds.)
The Complete Guide to Interpreting Your Dreams
by Stearn Robinson - Tom CorbettSee also Birds.