"How do you get these numbers?" you ask. Marjorie describes how she wades around the perimeter of Slow Water Park at noon, and counts the Rana viridiana frogs she sees.

"I'm an amateur," Marjorie says, "but that doesn't matter. The secret is in doing it enough times, the same way each time. When you've done it for years, you can tell right away if something's not right."

"Well, I'm convinced the frogs are in trouble." Carolyn looks at the herpetologist. "Now the question is, why?"

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(for explanation of chart,
click on it)