Giant invasive frogs are wreaking havoc on the West

On summer evenings in the Midwest, the muggy air comes alive with a chorus of crickets, cicadas, and frogs — especially bullfrogs. Their booming mating calls sound like something between a foghorn and a didgeridoo.

As far as we know, summer here has always sounded like this. Bullfrogs are native to most of the Eastern US, from the Mississippi River to the Atlantic Coast. They evolved here. They belong here. I, for one, adored them as a kid growing up in Iowa, and spent countless summer days trying to catch them to get a closer look.

What’s unusual is that a few states west — into Colorado and on to California — summer nights are similarly marked by the iconic call of the American bullfrog. But here, they don’t belong. They’re unwanted. And they threaten the very existence of some of the