They learn quickly.
Wholesale poisoning program here in B.C. back in the 50's. The ranchers, hunters and game branch tried to eliminate them. Poisoning cattle and horses for baits, poison baits dropped onto lake ice in the winter time. anybody and everybody was out to 'get them'.
All that did was to educate the survivors who took less than 20 years to overpopulate again.
When there are ranchers to feed them after the elk, moose, deer and caribou are wiped out to bare existance numbers, the normal peaks and valleys of wolf & ungluate populations by nature, doesn't happen.