Little Nimrod killed C.C Robin because he had discovered the poaching secret that Little Nimrod was keeping. The first piece of evidence is that there were dead birds in the grass. This fact is important because C.C Robin is an ornithologist, or bird expert, and Little Nimrod is a poacher this proves that when C.C Robin was observing birds Nittle Nimod killed them. One of the birds that both little nimrod and C.C Robin had taken interest in was a bald eagle. These types of birds are endangered and Little Nimrod had just killed one. This started a fight between the two men.Another piece of evidence is the axe marks in the tree near the campsite.This detail is important because it implies that an axe was brought to the campsite by Bernie Burger