A study by the Wyoming Cooperative Fish and Wildlife Research Unit shows that elk migrating to and from Yellowstone are raising fewer calves than in the past.
Report co-author Arthur Middleton says hot, dry weather has limited the amount of forage available, so fewer elk have been getting pregnant. Plus, he says wolves and bears are rebounding and killing more elk calves.
He says in contrast, non-migratory elk outside the park are doing well, because land is irrigated, and predators are scarce.
“One of the interesting things there is that we think of migration as a strategy to get better food and to escape from predators that make their dens near winter ranges,” Middleton said. “It actually seems like it’s the residents who in this case are starting to gain these dual benefits.”
Middleton says despite the decline in calves, migratory elk do not seem to be in danger of dying out.