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This is Scientific American's 60-Second Science. I'm Adam Hinterthuer. Got a minute?

If you're worried about news reports of West Nile virus, you might want to go take a census¹ of the birds in your backyard. Because certain species of birds actually help the virus thrive. And they're not exactly exotic jungle fowl². In fact, they’re our more familiar feathered friends.

Work on Lyme disease has shown how fragmented forests common around cities and towns are home to lots of white-footed mice, which carry that disease. Inspired by this look into the ecology of disease, researchers at Washington University turned their attention to West Nile virus. They analyzed³ mosquitoes around the St. Louis area and found that rural plots with robust⁴ populations of numerous bird species harbored fewer infected mosquitoes than more "citified" settings.

The typical urban or suburban⁵ backyard usually only holds a handful of bird species, like crows, grackles, house finches and robins⁶. And those birds are rich reservoirs for West Nile virus. Which ups the odds⁷ that a mosquito stalking a suburbanite⁸ may have recently fed on a bird carrying the virus. It's another example of how human activities alter the environment in unexpected ways that can often come back to bite us.

Thanks for the minute for Scientific American's 60-Second Science. I'm Adam Hinterthue