Elk migration

A rutting bull elk bugles under a colorful predawn sky in September in Grand Teton National Park.

Some of Wyoming’s feedground elk have likely been conditioned to expect food every winter, changing the way they migrate, according to a study published recently in the journal Ecological Applications.

Those elk spend almost a month less on their summer range in the mountains than elk wintering on their native grounds.

Feedgrounds shortening migration routes from summer ranges high in mountains and winter ranges in lower elevations isn’t really new, said Matt Kauffman, leader of the Wyoming Cooperative Fish and Wildlife Research Unit and co-author of the paper “Supplemental Feeding Alters Migration of a Temperate Ungulate.”

Supplemental feed began as a way to keep elk away from ranches, haystacks and livestock operations. It has also been controversial because elk clustered together in high densities are more likely to spread disease.

But biologists and wildlife managers did not know how much more time elk spend on the feedgrounds and what triggers their movements, Kauffman said.

The study also revealed an irony: While feedgrounds were established to keep elk away from lower ground, they are actually keeping them on nearby winter range for longer period of time.

“From an elk management, human rancher tolerance perspective, when elk are up on their summer range, that’s where we want them to be,” Kauffman said. “They’re spending less time there and presumably more time on winter range.”

Researchers began the study in 2008 and monitored elk on and off the feedgrounds for several years.

The study was a collaborative effort near the Wyoming and Wind River ranges between the cooperative unit, the University of Wyoming, the U.S. Geological Survey, the Wyoming Game and Fish Department and the Wyoming Geographic Information Science Center in Laramie.

Researchers found that elk on native winter ranges followed the first green plants into the mountains in the spring to take advantage of abundant summer food.

Elk put on most of the fat they need to survive throughout the winter when they’re in the mountains in the summer, Kauffman said.

In the fall, they stay in the mountains until snow is so deep that they’re forced into lower country.

Fed elk, on the other hand, leave feedgrounds much later in the spring. They also leave their summer range in the mountains earlier than unfed elk, generally after the first winter storm, he said.

“It’s potentially because the elk know that there’s going to be winter feeding. They know there’s a food resource for them in the winter,” Kauffman said. “It’s also possible that the unfed elk have developed a lifestyle where winter is harsh and there’s not free food, and they need to make the most of summer range.”

In total, feedground elk spend about 26 fewer days on their summer range than unfed elk. If or how that changes their body condition was not part of the study, Kauffman said.

Game and Fish officials did not anticipate the results, said Brandon Scurlock, brucellosis program supervisor for the department, who also co-authored the study.

They will use the information to update elk seasonal ranges to analyze where elk spend their time, he said.

The information will likely not change the way feedgrounds are managed, said Gary Hornberger, Game and Fish’s big-game feeding supervisor.

To prevent damage to crops or livestock, elk on feedgrounds near ranches or private land are fed until they follow green grass into the mountains.

Elk in remote areas not adjacent to private property are generally weaned off feed earlier.

“We’re going to keep going as is,” Hornberger said.

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Reach Assistant Content Director Christine Peterson at 307-746-3121 or christine.peterson@trib.com. Follow her on Twitter @PetersonOutside.




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