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Idaho Fish and Game

Seven Elk Dead after Grazing on Poisonous Plant


Seven elk are confirmed dead after grazing on a common – and deadly – landscaping plant in the Boise foothills near Table Rock.

A local sportsman alerted Fish and Game officers who found the dead elk scattered over a hillside just below Table Rock Road. What appeared to be a case of indiscriminant poaching quickly changed course. “None of the elk had bullet wounds or other obvious signs of trauma,” Fish and Game conservation officer Ben Cadwallader noted. “They all appeared to be in great shape, with adequate fat reserves and solid bone marrow; we concluded that we were dealing with some sort of toxin instead.”

Cadwallader and district conservation officer Bill London conducted field necropsies on all seven elk and took photos of the stomach contents. Fish and Game wildlife veterinarian Mark Drew confirmed the presence of Japanese Yew needles in each of the elk, leaving little doubt as to the cause of death. A small handful of yew needles is enough to kill an adult elk.Photo

Japanese Yew or Taxus cuspidata is a common landscaping shrub, despite the fact that its soft, waxy needles are fatal to a variety of species, including elk, moose, horses, dogs and even humans. While the plant presents little danger to wildlife in an urban environment, the foothills are another matter, where big game animals commonly roam during winter months.

Two source of the poisonous plant have already been located, but the search continues today. “What we do know is the plant quickly kills browsing elk,” Cadwallader said. “So other sources might be nearby.” Because of the risk to big game animals, the department urges all foothills homeowners to inventory their property and remove and landfill any Japanese Yew that might be growing at their residence.

Compounding this problem is a well-intentioned, but misguided foothills resident who is putting out hay, presumably to feed the herd of 200 elk wintering in the area. “Despite the winter weather, these elk are in great physical shape and they have adequate forage,” Cadwallader said. “The presence of hay only encourages these animals to stay in the immediate area which could lead to additional animals dying from ingesting Japanese Yew needles.” As with other big game herds across the state, Fish and Game staff are monitoring deer and elk herds wintering in the foothills and will take steps necessary to insure herd survival.