In a nutshell
We have often paid little tribute to the ancestors of domestic dogs and regarded them as wild murderers. Other enlightened views may consider wolves as predators killing herds of sick or weak animals. However, wolves are indeed masters of ecosystem engineers, and their activities are directly responsible for protecting migratory songbirds. Wolves exert top-down control over herbivore activity and can therefore prevent deforestation from decimating the breeding bird population.
The Whole Bushel
"Wolves are not our brothers; They are not our subordinates either. You are another nation, just like us, trapped in the complex web of time and life. "- Henry Beston
Wolves are often regarded as the worst killers and predators with at best a simple relationship with other animals. Wolves are regarded as damaging forces of nature that only cause the destruction of other species. Some writers considered the gray canines to be "the person of Satan" in the coat. Wolves were seen as bad for a supposedly good and abundant natural order that competed with humans and other animals for resources.
How foolish it now seems to regard part of the finely tuned machinery of nature as somehow out of place. A strong counter-attack to the wolf's view of being a harmful species is the discovery that wolves not only "kill" the flock of sick and weak animals, but also possess the keys to maintaining the order of entire ecosystems.
The Mighty Pine trees do not trigger wanton destruction, but instead pruning scissors owned by the Nature Regulators, who are surprisingly responsible for preserving the populations of our favorite migratory birds. In areas where wolves were returned, such as the Greater Yellowstone ecosystem, the elk population was inspected at wolf's return, resulting in significant changes in riparian vegetation.
As a result songbirds were bred like the canary-like Yellow Warbler. The return from South America enabled the repopulation of vast areas that had been cleared and cut down in the absence of wolves.
Show Me The Proof
http://www.bioinfo.rpi.edu/bystrc/ pub / artWolves.pdf