Moose Die from Chokecherry Poisoning
(Juneau) – Alaska Department of Fish and Game staff received confirmation this week of a third moose calf this year that died in Anchorage of cyanide poisoning after eating European bird cherry, also known as “chokecherry.” The department urges property owners to cover or dispose of their chokecherry and Japanese Yew clippings to keep them away from browsing moose.
“Cyanide poisoning can occur from any shrub in the Prunus family, more commonly called ‘chokecherry,’ but usually just after the first frost. It may be that recent warm spells in Anchorage followed by freezing temperatures led to several cases during mid winter,” stated Wildlife Veterinarian Dr. Kimberlee Beckmen.
Lab results have confirmed that two calves died in January and a third in February after they ate recently frozen chokecherry buds, branches and berries. The third moose also ingested toxic amounts of Japanese Yew which likely contributed to its sudden death.
Eating chokecherry buds, leaves or fruit is not typically dangerous for people or pets, but animals with segmented stomachs (rumens) including moose, cattle, goats and deer can be at risk, particularly soon after the plants freeze. When the buds are chewed and swallowed, they react with chemicals in the rumen to release cyanide gas which can kill a moose as quickly as 20 minutes. Japanese Yew is toxic at all times and is more poisonous to people and pets as well.
“When we seen skinny moose that have died in towns and yards, typically we assumed they died from starvation, but these recent cases highlight the fact that is not necessarily the case,” Beckmen said.
Biologists found these three cases of cyanide poisoning while examining carcasses for evidence of disease introduction and spread in moose. “It’s possible that more moose die each spring as a result of cyanide poisoning, but we don’t have the personnel or resources to examine and test them all,” Beckmen said.
The most likely parts of the plant to produce cyanide are the buds and frosted leaves. Branches that have been pruned from chokecherry trees can also present a danger. “Property owners should make sure the clippings aren’t available to moose,” Beckmen said. In the most recent case, the calf had been browsing on chokecherry prunings stored under a porch that contained high levels of the toxin.At least three species of chokecherry grow in Alaska, but are not native plants. They are commonly planted as ornamental plants that have spread and become an invasive species by displacing native vegetation that moose prefer to eat such as willow. The European bird cherry, Prunus padus, is now the dominant vegetation along many of the streams running through the Anchorage greenbelt.