While this might seem a bit over-the-top, wildlife officials are willing to do anything to get rid of the brown tree snakes in Guam. Apparently, these mildly venomous serpents are an invasive species that has devastated native animal populations on the Pacific island. From the BBC:
"The brown tree snake has had a devastating impact," Cheryl Calustro of Guam's Department of Agriculture, told the network. "Ten out of 12 native forest bird species disappeared in 30 years. The birds here evolved without predators. They were quite naive. And when the snake arrived on Guam it ate eggs, juveniles, adults. Whole generations disappeared."
As for the chances that other animals might ingest these poisoned rodents, scientists have even got that covered:
"Right now we are using acetaminophen," the U.S. Agriculture Department's assistant state director Dan Vice told the BBC. "It's commonly used as a pain reliever and fever reducer in humans, but it is 100 percent lethal to all brown tree snakes."
While no one knows exactly how these brown tree snakes made their way to Guam, they're believed to have stowed away in military cargo shipped from Papua New Guinea during World War II.

So if it's raining mice in your area, chances are you're either in Guam or brown snakes are invading your territory.