water or environment with feces from infected birds. It can also be spread through predator attacks where the bird survives the attack from a raptor such as a hawk， crow， or other flying predator. ， eagle， owl， Trichomonas gallinae is a protozoan parasite known for causing canker in birds. T. gallinae is predominately a cosmoplitan parasite of pigeons and doves， however other domestic and wild birds can become infected if they are exposed to it. Transmission: T. gallinae is generally found in the oral-nasal cavity or anterior end of the digestive and respiratory tracts of infected birds. T. gallinae is usually transmitted to poultry through contaminated feed，。