Oconto, Wisconsin is a small town on the western shores of Green Bay. It was here that French Jesuit missionary Father Claude-Jean Allouez held the first Roman Catholic Mass. It is also the home of Copper Culture State Park - an 8,000 year old Indian burial ground that is considered to be the oldest cemetery in Wisconsin and one of the oldest in the entire nation.
In two days during the summer of 1952, an estimated 175,000,000 Leopard frogs emerged from nearby marshes and enveloped the town. "The explosions of amphibians beneath the wheels of automobiles at night sounded like rifle fire. People mowing their lawns did so in a storm of flying frog legs and truncated frog bodies."
Marshes near Oconto had never seen frogs in such numbers.
"Typically, the water level of Lake Michigan would rise in the spring, wetlands would flood, leopard frogs would lay eggs, and when the lake level receded with the advance of summer, most of the eggs would die. But in 1952, Lake Michigan remained high. And inconceivably huge numbers of gelatinous frog eggs grew into hungry, live amphibians."
"A man I know said they had besieged his house one night in what he swore was a highly organized way. He had gone out on his front lawn to have a look around with his flashlight and had been confronted by a million shining little eyes. He started toward the back yard and found that he had been outflanked. He swung the light around and discovered that the whole house was encircled. It was a scary thing to see, he said."
Summer wore on, nothing could be done. Few mosquitoes were seen that summer. Eventually, the frog population began to dwindle. It never happened again