Yes, Cockatiels, Cockatoos, African Grays and Pigeons. These are called "powder down" birds. They are extremely dusty and cause the most irritation to people with allergies and other respiratory problems. Unlike most other birds that shed and replace their feathers via a process called molting, powder down feathers grow constantly and eventually disintegrate into a fine, waxy, talcum-like white powder. They are capable of producing large quantities of this powdery dust on a daily basis to coat the floors, furniture and other surfaces of the rooms in the birds in question are caged.