I'm not at all certain that the US could have settled by the early explorers if the coyote, Canis latrans, had been present East of the Mississippi. It was absent then but is now abundant and it could have been disastrous to early farmers and their livestock. Wolves were a problem for settlers, but an Eastern coyote would have made survival almost impossible.
Here is a coyote on early patrol after a light snow in Virginia last month. The photo is shared by Mark Wiley of Radford, Virginia.
Throughout the West, attempts to exterminate the coyote were carried on for a century by federal and state programs. It was harmful to ranchers' small animals, to sheep, rangeland calves, and to wildlife. Reduction programs could not be sustained, many were ineffective, and new public sentiment against control became strong.
When I was a state wildlife biologist in the early '60s there were no coyotes (or only a "curiosity" and unexplained road-kill). Now they have been transplanted or they have found highway bridges and other clever ways to expand into new territory. Trappers have learned that they are very clever and prolific.
There will now emerge new efforts to keep their populations below a studied level. They cannot be allowed to increase un-regulated. They are now fearless of humans for they, now without guns, pose no perceived threat. (See Will N. Graves 2007. Wolves in Russia: Anxiety Through the Ages, Detselig Enterprises Ltd, Calgary, Alberta, Canada, 222p.)
Coyotes are now taking house cats and dogs. Small birds, rodents, reptiles and small game are usual foods. Some sheepherders in the East now have given up in the face of their losses. Rabies virus strains will shift to them as it has from raccoons to skunks and back again. Wildlife are less of a concern now to a shrinking hunter population but I think that the coyotes' effect on the deer fawn crop may be the only good thing that will result from their invasion. Their predation on fawns will limit deer population expansion (already deer heavily damage crops,forests, and landscape plants and deer populations are beyond control by current hunters).
Active groups of people in love with coyotes and wolves, seemingly uncaring about their actual and potential harmful effects, make faunal system management very difficult and make clear the essential relations of changing faunal space, populations, and human behavior cost-effectively over time toward desired ends.
Telesco's notes on species specific management of the coyote resource may provide useful insights to the requirements ahead.