Meanwhile more and more visitors have the opportunity to see wolves through their binoculars and spotting scopes. This is particularly true in the Lamar Valley, where the large Druid Peak and Slough Creek packs den each winter. Through the introduction of wolves to Yellowstone, the whole ecosystem is changing, from the grizzlies to the cougars, coyotes, and ravens who all profit directly from wolf kills, on down through the ecological pyramid.
The wolves primarily prey upon elk. Now fewer elk graze on the aspen and willows, which in turn are increasing on the elk’s northern range, creating more habitat for small animals and birds like warblers. The Yellowstone area is again becoming a remarkable example of what James Halfpenny, in Yellowstone Wolves in the Wild, calls a trophic cascade profound effects spiraling down from the top to the bottom of the natural food chain.