Didn't read the field guide

Some organisms are very predictable. They are always found in particular places or situations doing particular things or growing in certain ways. Sometimes, though, those organisms defy our expectations and do something or occur somewhere totally weird. When that happens, Herb likes to say, "That (animal/plant) didn't read the field guide!"

So here I have a plan for an experiment. It's based on particular things occurring or not occurring in particular places. I was nearly through setting up in a site that wasn't supposed to have this thing, and OH NO there it was. That thing obviously didn't read my experimental plan.