Canker / Giardia

Canker/Cochlosoma is the most commonly encountered Protozoal disease in aviculture. It can devastate finches and canary breeding flocks and is a significant disease in exhibition canaries.
The cankers are often large yellowish masses in the throats and crops of birds
Many other effects are seen from Trichomonads.

Symptoms of Protozoal Diseases:

diarrhea
canker or large yellowish masses in the throat or crop
weight loss
yellowish/green droppings
dirty feathers around the vent
regurgitation
dried saliva around beak