While bird flu gets a lot of attention, West Nile virus in birds is also worth knowing about — including what to do if you see a sick bird.
When we watch birds, we accept that sometimes we’ll witness things that are unsettling. Birds of prey feeding on songbirds, victims of window strikes, obviously sick or injured birds — inviting birds into our lives means dealing with any or all of these things. While backyard birders might not be aware of every illness by name, one wild bird disease you’ve probably heard of is West Nile virus. Here’s what to know about West Nile virus in birds, including how to spot the symptoms of a sick bird.
How Does West Nile Virus Spread?
While West Nile in birds might be unfamiliar to you, it’s not an unfamiliar concept. The virus has been present in the United States since 1999. While humans can become infected, severe illness is rare and occurs in less than 1% of cases.
“West Nile, since it’s mostly mosquito-borne, it’s not as big of a concern as bird flu would be — that’s more transmissible by contact,” says Dr. Lina Rifai, associate professor of vertebrate biology at Indiana University-Kokomo. While transmission by secretions is technically possible, the most common way that the virus spreads is by bites from infected mosquitoes.
West Nile Virus Symptoms in Birds
West Nile affects more than 250 species of birds, but corvids — jays, crows, magpies and ravens — have the highest rate of susceptibility to the virus along with raptors. Affected birds often appear disoriented, off-balance, and unable to fly. Their wings may droop, and they may tilt their head or have tremors.
“Most humans infected with the virus will survive, and the same is true for many bird species,” say birding experts Kenn and Kimberly Kaufman. “Exceptions include crows and jays, for which the virus is very often fatal; the crow population in some places has been seriously depleted by West Nile virus.”
West Nile Virus at Bird Feeders
Unless a bird has been tested for West Nile virus, you’re not likely to know for certain whether a sick bird in your yard has the disease. “Raptor rehabbers and bird rehabbers often say they still see a lot of West Nile in birds that come in, but unless they test for it, we don’t know if it’s increasing or decreasing,” Lina says.
Regardless, Lina recommends exercising caution and following best-practice procedures if you see a sick bird at your feeders. She says birders should take feeders down and clean them well. In addition, they can check with their state’s DNR for any current West Nile warnings. If a birder has to handle a dead bird, always wear gloves. Place the dead bird in a bag, and put the bag in the garbage.
While West Nile virus in birds hasn’t gotten the same level of attention that avian influenza has in the news, and it doesn’t commonly transmit from bird to bird without using mosquitoes as a vector, Lina still thinks it’s a good idea to stay aware. “I think it should get more attention because it’s affecting our wild bird populations,” she says.
About the Expert
Dr. Lina Rifai is an associate professor of vertebrate biology at Indiana University-Kokomo. She earned a Ph.D. in behavioral ecology from the University of Louisville.
Kenn and Kimberly Kaufman are the official bird experts for Birds & Blooms. They are the creators of the Kaufman Field Guide series and they lead birding trips all over the world.
Sources
- Cornell Wildlife Health Lab, “West Nile Virus“
- U.S. Centers for Disease Control and Prevention, “West Nile and Dead Birds“
- Cornell Lab of Ornithology, “How Can I Tell If A Sick Bird Has West Nile Virus?“
