The mysterious song-bird killer

 “In 2005, a disease was discovered in finches in the United Kingdom. In the years since, it has killed about half a million birds.” says Whitney Kelly-Clark, a master’s student in the Department of Pathology and Microbiology in UPEI’s Atlantic Veterinary College. “It appeared two years later in the Maritimes, and now we’re trying to find out how it spreads from bird to bird.”

The disease is called trichomonosis, and is caused by a microscopic parasite called Trichomonas gallinae.
“The disease causes cankers in the bird’s throat, similar to a canker sore we would get in our mouth,” says Kelly-Clark. “These sores become so painful, the bird can’t eat or drink. It ends up dying of dehydration or starvation.”
While scientists understand the disease is caused by the parasite, they’re still not sure how the parasite is spread from bird to bird.
“There is speculation it is spread at bird feeders, but that has not been confirmed,” says Kelly-Clark. “We’re recreating bird-feeder conditions in a lab, and seeing whether the parasite can live long enough in that environment to spread.”
Pigeons and doves are known carriers of the parasite, but in our region, it only causes sporadic mortality in those species, not like the significant widespread mortality we observe in our Maritime finch populations..
“And we’ve known that about pigeons and doves for nearly two hundred years,” says Kelly-Clark. “Falconers noticed their birds were becoming infected with a deadly disease after eating pigeons or doves. We’re still trying to understand what has changed in the disease so that it now infects songbirds.”
The disease was first discovered in the European green finch, but has gone on to infect 10 different species in the UK. In the Maritimes, it’s infecting purple finches and the American goldfinch.
“We’re asking people across the Maritimes to keep an eye out for infected finches at their feeders,” says Kelly-Clark. “It’s only through the public’s assistance that we can track this disease as it progresses.”
For more information of what to do if you find a sick or dead bird, see this poster published by the Canadian Cooperative Wildlife Health Centre.
Kelly-Clark's supervisors are Dr. Spencer Greenwood, assistant professor of Biomedical Sciences; and Dr. Scott McBurney, Clinical Veterinary Professional-Wildlife Pathologist at the Atlantic Veterinary College and the CCWHC.