A pediatric nutritionist is a registered dietitian (R.D.) that has specialized in nutrition for children, so you must first become a registered dietitian. You could enroll in a bachelor's degree program accredited by the Commission on Accreditation for Dietetics Education.
Here is part 1 of Cockatiel Types and Descriptions which covers 5 types of cockatiel types including whiteface, lutino, albino, normal greys, and pied. Each ... Here is part 1 of Cockatiel Types and Descriptions which covers 5 types of cockatiel types including whiteface, lutino, albino, normal greys, and pied. Each slide gives a bried description of what each type looks like, and includes a photo. Please watch part 2 for more types. Thanks for watching. :) I own none of the photos shown in the following video.
Cockatiels can be bullied by smaller but more dominant birds such as budgerigars (budgies) and most particularly parrotlets (Forpus). However budgerigars may over-preen the cockatiel's plumage, causing bald spots.