Frounce

The organism

Trichomonas, a protozoan parasite of the digestive tract. In raptors the disease is called frounce; in pigeons the same organism causes canker. It affects the digestive system.

What you see

Open the bird's mouth and you find a cheesy cream-yellow growth, at the corners of the mouth (the "gape"), around the tongue, on the roof of the mouth. Alongside it: weight loss and flicking food away. Those three together are frounce.

It is not self-limiting. Untreated, the bird often dies a week to ten days after the oral masses appear. The mouth overgrows with hard plaques, breathing becomes difficult and feeding becomes impossible.

Where it comes from

Chiefly from eating an infected pigeon. Feral pigeons, doves, European Starlings and House Sparrows all carry it. The manual notes that in some places 80% of feral pigeons are infected, and that a wild mourning dove is the most likely source of disease among the birds your hawk might catch. Standard practice is to remove the head and crop of any pigeon before feeding it.

Prevention and treatment

Feed food animals from trusted sources only. Monitor the bird's mouth. The manual names Emtryl as the most practical weapon against frounce, with early intervention doing most of the work. Treatment, as always, goes through your veterinarian.