Numerous birds consume the fruits of the Yew tree (Taxus baccata), which are actually arils rather than berries. They, or rather, the seeds they contain, along with the plant’s leaves and other parts, are extremely poisonous. It only takes 500g to kill a cow and 100g to kill a horse when they graze from the branch.
https://www.ncbi.nlm.nih.gov/pubmed/18793664Acute yew (Taxus) intoxication in a free-ranging moose (Alces alces) is reported. The moose was found dead without any signs of struggle and post mortem examination revealed general congestion, bilateral heart dilatation, and the presence of yew in rumen. The animal was found adjacent to a housing estate with unfenced gardens, surrounded by woods and open fields without native yew. The vast majority of the gardens contained cultivars of yew that had frequently been browsed upon. These were the most likely source of intoxication. This is believed to be the first report of yew intoxication in a wild animal species. It is concluded that yew intoxication may be an overlooked diagnosis in wild deer, and the general opinion that deer species are naturally resistant to many plant-associated toxins is discussed.
www.petpoisonhelpline.com/poison/japanese-yew/This common evergreen (meaning the plant stays green all year round) is extremely poisonous to all species (e.g., dogs, cats, horses, cattle, humans, etc.). All parts of the plant (including the succulent, red berries) are very poisonous, as they contain taxines. There are several variety of plants in the Taxus spp., including the Japanese Yew and English Yew. When ingested by dogs and cats, clinical signs of drooling, vomiting, weakness, difficulty breathing, life-threatening changes in heart rate and blood pressure, dilated pupils, tremors, seizures, coma and death may be seen. Recently, florists have started to use Japanese Yew to make wreaths for the holidays. As horses are very susceptible to yew poisoning, make sure not to have this around the barn or pasture!
It is unexpected that a family of bears perished from eating the seed if it is the poisonous portion of the aril because bears typically ingest seeds whole and pass them through undamaged. I do recall one bear, though, who did crack his seeds, so you never know.
Happier news: for a short while, a red squirrel paused and relaxed on a branch outside the window. I know how that feels. I occasionally need to take a 30-minute nap to clear my head. The squirrel survived on less, and it did so with its eyes open. If it’s feasible, they must remain vigilant even when they sleep. I remember the deer I used to walk with. They would chew food until they could swallow it in order to consume it. Usually in a thicket of balsam fir where they could see out beneath the branches, they would go to a spot where they were partially hidden but could still see around after they had eaten a good deal. There, theyd chew their cuds. They would eventually tuck their heads and sleep for a brief period of time. Then they were up foraging again. Today, the squirrel became alert and began running down the branch and down the tree to resume gathering sunflower seeds.
Id never heard about anything like this with bears. All I knew about the native yew (Taxus Canadensis) of the Northeastern United States was that, during times of abundant deer populations, white-tailed deer eradicate them through browsing. I never heard of a deer dying from it. I looked it up on the internet just now. White-tailed deer apparently are resistant to yew toxins.
FAQ
Do birds eat the berries on yews?
Can squirrels eat yew berries?
Who eats yew berries?
What animals eat yews?