Beavers eating conifers

Will beavers eat conifer trees?

—Karl Dennhardt, Kahshe Lake, Ont.

Yes. But only when desperate, the way you might eat a hot dog from a gas station. Conifers are “emergency food” for beavers, says Franco Mariotti, a staff biologist at Science North & Dynamic Earth in Sudbury. Mariotti suspects the tannins and sap in the trees are deterrents to the beavers. “The bark probably tastes bad,” he says. They prefer to chow down on hardwoods such as birch and poplar, as well as aspen, alder, and willow—though they have been known to eat all sorts of plants, including grass and poison ivy. 
In the summer, they like aquatic vegetation such as cattails and lily pads, which Mariotti has seen them fold, like tortillas, before devouring.

If beavers are chomping on your conifers, the damage will show the “typical chewy pattern in an hourglass shape around the trunk,” says Chris Heydon, a fur program biologist with Ontario’s Ministry of Natural Resources. Or it may be a little less obvious, Mariotti says, until you look closely for teeth marks 
at beaver height, about half a metre from the ground.

If the beavers are eating conifers, that “tells a whole story,” Mariotti adds. “They’re out of normal food, and they’re likely to move on in the near future, since it’s questionable whether they can survive on conifers alone.”