Any bird may be affected by Aspergillus species, but it is most commonly associated with birds of prey and with parrot species that are taking a seed-based diet.

C. albicans can be a primary gastrointestinal pathogen, especially in finches, but it is more frequently secondary to another problem. 

Megabacteria is actually a yeast organism called Macrorhabdus ornithogaster, or avian gastric yeast.