There are now millions of snakes but virtually no native birds left on Guam. NBC News reports the latest attempt at snake abatement is to bait the snakes with mice laced with acetaminophen (aka Tylenol), a drug which poisons only the snakes.
The DrsC were visiting faculty at the University of Guam for a year in the mid-1980s, and noticed this lack of birds. We spent part of Christmas break that year touring New Zealand.
One EnZed morning we marveled at the riotous sound of hundreds of birds greeting the dawn at the top of their tiny lungs. Sadly, it's a sound not heard on Guam for decades.