A strange paralysis could be affecting crows closer to home
A mysterious paralysis has been killing crows and ravens in northern B.C., and now some Islanders are concerned the unusual deaths could be much closer to home.
“I have noticed several dead crows on the sidewalk over the past few days,” said Vancouver Island Oak Bay resident Bill Smith in a letter to the News, noting that some crows were seen struggling to walk. “I decided to Google ‘dead crows’ and was quite surprised what I found … Let’s hope this is not the start of a serious problem.”
Scientists at the University of B.C. and residents have murmured concerns that the northern birds could be showing indications of West Nile Virus, especially as the corvids are most susceptible and often act as an early warning system. However, B.C. has not had any reports of West Nile in humans since 2010, and the province does regular testing of the mosquitoes in different regions of B.C.
Oak Bay manager of parks Chris Hyde-Lay said the district has had no official reports of dead crows this year. However, birds are typically disposed of and are not sent for testing.
Leona Green, who runs the Hillspring Wildlife Rehabilitation facility in Dawson Creek and received calls about the unusual dying corvids, says she has had dozens of reports of the paralyzed or dead birds since the end of May. While, at first, she had been instructing people to safely dispose of the birds, the increased calls in the past two weeks surprised her.
On July 30, with upwards of 25 birds brought to her, she sent six specimens to be autopsied by the provincal Animal Health Lab – protocol when non-typical deaths occur in species. Results are expected within two weeks.
“I’ve never seen anything like this. The birds are alert, their wings move, but their legs are paralyzed from their spine. We are really scratching our heads over this,” Green said. “Being as I am not really a scientist, I can’t confirm what it might be, just that I’ve sent the samples off, and that’s all we know for now.”
So far in Canada this year, two samples of mosquitoes and one bird have tested positive for West Nile in Ontario. No new activity has been reported from Washington State, however new positive mosquito samples have been found in Oregon, Idaho and California.
“It is extremely unlikely that the birds in the Peace River area have West Nile Virus,” said provincial vet Helen Schwantje. Although corvid deaths are not unusual, Schwantje suggests the public report any number of species dead within close proximity to each other to the Interagency Wild Bird Mortality Investigation Protocol, and the B.C. Centre for Disease Control.
The act of testing is paramount said Brian Starzomski, assistant professor of environmental studies and ecology at the University of Victoria. While Starzomski said he, too, has seen dead crows in the area this year, there are many reasons for death, which could include young-bird mortality rates, species-specific diseases or even poisons in the region.
“It is extremely important to reports birds, especially in cases where we see unusual death, and it’s in everyone’s best interest to make sure these numbers are tracked,” he said. “Mosquitoes transfer diseases from disease-bearing animals, so they become the conduits, so to speak.”
Dr. Richard Stanwick, Chief Medical Health Officer for Vancouver Island Health Authority, said while it’s extremely unlikely that West Nile has entered B.C. or the Island, that doesn’t mean people should let their guards down.
“We have to consider how our climate is changing, and that means the mosquitoes are seeing a longer breeding season and have more opportunity to progress through the cycles,” said Stanwick. “We have been very fortunate to live in a zone that is considered relatively safe but, with many diseases, it’s really just a matter of time.”
At least 13 identified species of mosquitoes inhabit the Island and Stanwick said that, while birds like crows are most susceptible in their interactions, simple precautions are still important for humans, especially when around water-based and forested areas: precautions like using a repellent, staying in at dawn and dusk or keeping covered.
“The thing about West Nile is that it is a very interesting virus, and we can’t say how it will react in everyone,” said Stanwick. “Certainly, it can cause very serious conditions, and people here do travel a lot, so it is something they need to be aware of. However, there is a much greater chance they could contract it somewhere else.”