PROLOGUE: I'm in the middle of enjoying spring weather and great fishing at DePuy Spring Creek (www.depuyspringcreek.com) in Paradise Valley, MT. I may be supposed to update my blog or tie more flies in my house but I asked the editor to let me write about a very interesting situation I'm experiencing at the creek. It's amusing: what really makes a spring creek technical and challenging. At a certain spot of the creek, insect hatches and trout behavior are offering me a very enjoyable yet very challenging situation.