Elk have a weakness for winter wheat.
"It is a bit addictive (for elk),'' said Oregon Department of Fish
and Wildlife biologist Mark Kirsch, who is based in Pendleton.
This addiction got the best of at least 250 young elk this winter, including many that had migrated from Union County, in the McKay Creek area southwest of Pendleton. The elk, 200 of which were calves, died because they had gorged themselves on winter wheat for months, Kirsch said.
The winter wheat did the young elk in because their digestive systems cannot break it down and absorb its nutrients. This means some elk actually died of starvation because they were not absorbing nutrients from the winter wheat.
"They starved to death on full stomachs,'' Kirsch said.
Most of the elk that died likely succumbed not to starvation but to Clostridium infections, Kirsch said. Clostridium is a bacteria found in elk. It attacks the bodies of elk when the animals are weakened by poor nutrition and other factors compromising their immune systems.
None of the dead elk ODFW biologists found at McKay Creek died from bloating, Kirsch said. Bloating often occurs when elk abruptly switch from dried cured forage in the winter to fresh vegetation like winter wheat.
Many elk succumbed from over-eating winter wheat in the McKay Creek area this year because winter conditions hit Northeast Oregon about a month earlier than normal, Kirsch said. This meant elk coming to the McKay Creek area began eating winter wheat a month earlier than normal.
Elk find winter wheat especially tasty from December through February when almost all the forage available is hard and cured. Once elk discover a winter wheat field, they know no better than to gorge on it.
"It is like giving a young kid the key to an ice cream shop,'' Kirsch said.
Many elk left the McKay Creek area for higher elevations when periods of warmer weather hit and returned when conditions worsened. Unfortunately some elk refused to leave, remaining despite the ODFW's best efforts. ODFW personnel tried to haze the elk off the winter wheat throughout the winter, Kirsch said. Using firecrackers, spotlights, four-wheelers and more ODFW personnel tried to harass elk off the winter fields. ODFW crews hazed the elk five nights a week all winter, Kirsch said.
Some of the elk were successfully run off, but some would leave only to soon return. Others, to the amazement of biologists, refused to leave at all.
"We were not polite. (The elk) weathered a lot of abuse every night,'' Kirsch said.
The biologist said he doesn't know why almost all the elk that died were calves or yearlings, but he has several theories. He said it may be that adult elk are more capable of digesting winter wheat than calves and yearlings. The larger size of adults may also be a factor, Kirsch said. Adult elk can go longer without eating or eating well because they have more fat reserves.
About 3,500 elk converged on the winter wheat fields of the McKay Creek area this winter. More than half these elk had migrated from the Starkey Unit, Kirsch said.
The last time there was a major dieoff in the McKay Creek area due to elk over-eating winter wheat was 16 years ago. The magnitude of the die-off in the winter of 1994-95 was not as great because only 1,600 elk were drawn to it.