Its a problem identified in Germany and attributed to a recurring problem we have on the South Common in Lincoln where a lot of Frogs die when the authorities aren't looking. The jury is still out where our mass frog deaths are concerned. Some people think it's mindless thugs killing the frogs (just how mindless would you have to be) Others thinks it is predators trying it on with the frogs then not liking the taste so leaving the carcasses. I trully hope that nobody could be that mindless and destructive - if its nature so be it.