Since individual birds vary in size, even within species, the most important thing you can do to make sure you order the right size is to measure your bird using these instructions.

Use a soft fabric measuring tape. Measure all the way around the bird's neck, full circle. Then, measure down your bird's back, from nape of the neck to the top of the tail.

Species Size
African Grey (Congo) 408XS
African Grey (Timneh) 408XS
Amazon 408XS
Amazon (Lilac Crowned) 408XS
Amazon (Panama) 408XS
Amazon (Yellow-Naped) 408XS
Bourke Parakeet 404X
Budgie (American) 404X
Budgie (English) 404X
Caique 406XS
Cameron (African Grey) 410XS
Cockatiel (larger with girth = 6.5") 406XS
Cockatiel babies (Under 6 months) 406XS
Cockatiel (Over 6 months) 406XS
Cockatoo (Bare Eyed) 408XS
Cockatoo (Citron) 408XS
Cockatoo (Ducorps) 408XS
Cockatoo (Eleonora) 410XS
Cockatoo (Goffin) 406XS
Cockatoo (Greater Sulphur Crested) 410XS
Cockatoo (Lesser Sulphur Crested) 408XS
Cockatoo (Medium Sulphur Crested) 408XS
Cockatoo (Moluccan) 410X - 412XS
Cockatoo (Rose Breasted - Galah) 408XS
Cockatoo (Triton) 410XS
Cockatoo (Umbrella) 410XS
Conure (Black-Capped) 404X
Conure (Blue Crown) 408XS
Conure (Crimson Bellied) 404X
Conure (Dusky) 404X
Conure (Fiery Shouldered) 404X
Conure (Golden) 408XS
Conure (Green Cheek โ€“ smaller with a girth of approx. 5.5") 404X
Conure (Green Cheek โ€“ average with a girth of approx. 6") 404X
Conure (Half-Moon) 404X
Conure (Jenday) 406XS
Conure (Maroon Bellied) 404X
Conure (Mitered) 408XS
Conure (Nanday) 408XS
Conure (Patagonian) 408XS
Conure (Pineapple) 404X
Conure (Sun) 406XS
Conure (White Eyed) 406XS
Crow 408XS
Dove (Ring Neck, smaller) 406XS
Dove (Ring Neck, larger) 406XS
Eclectus (Grand) 408XS
Eclectus (Red Sided) 408XS
Eclectus (Solomon Island) 408XS
Eclectus (Vos Maeri) 408XS
Indian Ring Neck 406XS
Jardine 406XS
Lorie (Rainbow) 406XS
Lorie (Smaller) 406XS
Lorikeet, Rainbow (Australian) 406XS
Lorikeet, Red Collar (Australian) 406XS
Lorikeet, Scaly (Australian) 406XS
Lovebird (Most) 404X
Lovebird (Smaller) 404X
Macaw (Blue & Gold) 410X
Macaw (Blue & Gold - Larger) 412X
Macaw (Green Wing) 412X
Macaw (Hahns) 406XS
Macaw (Hyacinth) 412X
Macaw (Illigers) 408XS
Macaw (Military) 410X
Macaw (Red Headed) 406XS
Macaw (Scarlet) 412X
Macaw (Severe) 408XS
Macaw (Yellow Collared) 406XS
Parakeet (Alexandrine) 406XS
Parakeet (American) 404X
Parakeet (Canary-Winged or BB) 404X
Parakeet (Lineolated) 404X
Parakeet (Moustache) 406XS
Parrot (Australian King) 406XS
Parrot (Hawk-Headed) 406XS
Parrot (Myers) 406XS
Parrot (Red Bellied) 406XS
Parrotlet 404X
Pigeon 406XS
Pionus 406XS
Pionus (Maxmillian) 406XS
Quaker 406XS
Senegal (African) 406XS
Starling 404X