[header] How to treat conjunctivitis in cockatiels [title] Get your bird examined by an avian vet. [step] The condition can be caused by a lot of different things, such as bacteria, fungi, nematodes, protozoa, and injury. Your vet will examine your bird, including lifting the eyelid. 
They may also test the discharge from the area to look for a bacterial or fungal infection. Your vet will also determine if your bird has an upper respiratory infection, since they can cause conjunctivitis.