Victoria Park mass crow deaths likely caused by virus in winter roosts, researchers say

Investigators say they may have an answer as to why hundreds of crows were found dead or sick in the Victoria Park area of Charlottetown this winter.

A team at the Atlantic Veterinary College in P.E.I. which had been looking into the deaths since January has wrapped up its investigation. 

AVC wildlife pathologist Laura Bourque was part of the team. 

She said they now believe the cause is corvid orthoreovirus, a somewhat newly described virus which causes mass mortality among crows congregating in winter roosts.

"We did a complete necropsies on the better preserved ones," Bourque said. "They had really bad inflammation and necrosis of their gastrointestinal tract. And that's pretty characteristic of a number of different types of diseases, but one that we think of often [is the] orthoreovirus."

Bourque said a case of the virus was confirmed in one of the crows, and that the investigators are "pretty confident" it was also behind the rest of the deaths. 

"Everybody is aware that crows like to roost in these very dense, very large colonies, particularly in Victoria Park," she said. "And that's a very good scenario for transmission of this disease, which is quite infectious."

The team is still looking to do further confirmatory tests before writing a final report. 

Bourque said not much can be done to prevent the crows from contracting the disease, which has been the cause of deaths among the species — and has been recorded for a long time.

"We'll continue to monitor the situation, but I believe this disease is going to have to run its course, unfortunately" she said.

"Once there's a mount of immunity built up in the population, hopefully the crows will be able to rebound adequately. And usually that's the case when these events happen. Crows are very resilient creatures, and I expect that we'll see that population perk back up again in the coming months."

And while the virus does not present any danger to people or their pets, Bourque said it's still better not to handle any dead birds as they can still harbour a number of diseases which can be passed to people.