We are conducting a giant experiment with no control and no way to stop it. The other reason for studying ecology is purely because it's interesting. Probably most ecologists get interested in ecology to save the world, but get intrigued enough by its complexity and intrinsic attractiveness to stay interested. MacArthur studied the niche separation of 5 warblers in spruce forests of NE N. America.
Warblers glean insects from vegetation.
MacArthur found that, in general, each species spent most its time in a different part of the tree. Morse studied warbler habitat association on offshore islands lacking in some species. Competition between the two is asymmetric. The book discusses the method of using a crane to study forest canopies. One well-known crane is in the forest in Washington near the Columbia Gorge, the Wind River Canopy Crane.