Plants:
There many harmful plants for you're cockatiel, in the list below are some harmful plants.
Be aware not all harmful plants are in the list.
If you know some more harmful plant please send a email and we add them to the list.
 

Aconite
Agaric Mushroom
Alacia
Amaryllis bulbs
Autumn Crocus
Avocado
Azalea Balsam

Jack-in-Pulpit
Jasmine
Java Bean
Jimsonweed
Juniper
Juniper
Saffron
Sandbox Tree
Scarlet
Skunk Cabbage
Snowdrop
Spindle Tree
Baneberry root
Bird of Paradise
Black Locust
Bleeding Heart
Blue Flag
Bluebonnet
Blue-green Algae
Boxwood
Bracken Fern
Broomcorn Grass
Buckeye
Buttercup
K Taro
Thorn apple
Tobacco
Tomato All green parts
Trumpet
Cabbage
Caffeine
Caladium
Calla Lily
Candelabra Tree
Cardinal Flower
Castor Bean
Chalice Vine
Cherry
Chestnut
Chinaberry Tree
Christmas Tree
Clematis
Croton
Crown of Thorns
Lily of the Valley
Lima bean
Lobelia
Locoweed Lords
Lupines
U
Daffodil
Daphne
Datura
Deadly Amanita
Death Camas
Dumb Cane
Mandrake
Mango Tree
Marijuana
Marsh Marigold
May apple
Meadow
Mescal Beans
Mistletoe
Mock Orange
Monkshood
Moonseed
Morning Glory
Mountain Laurel
Mushrooms
Virginia Bower Coral
Virginia Creeper
Eggplant
Elderberry
Elephants Ear
English Ivy
English Yew False
Narcissus
Nightshade
Nutmeg
Water Hemlock
Western Yew
Wisteria
Fichus
Firethorn
Foxglove
Oak (Foliage, acorns)
Oleander
Onion
X
Gostweed
Glory Bean
Ground Cherry
Peach
Pear seeds
Pencil Tree
Periwinkle
Philodendron
Pigweed
Pine
Poinsettia
Poison Ivy
Poison Oak
Pokeweed
Potato
Pyracantha
Y
Henbane Fly
Honeysuckle
Horsetail
Hyacinth
Hydrangea
QZ
Indian Licorice
Indian Turnip
Inkberry
Iris
Ranunculus
Red Maple
Rhubarb
Rosary Peas