This story was originally published in May 2018.
When it comes to looking for a new home, beavers are not ones to ask permission before setting up housekeeping in the ponds or streams of Maine’s small landowners.
“Whether it’s good or bad having [beavers] on your property is completely in the eye if the beholder,” according to Griffin Dill with University of Maine Cooperative Extension. “You need to ask yourself if you can tolerate them or if their presence is causing actual harm to your property.”
New construction
It is not at all uncommon for the aquatic, fur-bearing mammal to move into a small pond or along a waterways running through a yard or field.
Given that beavers are often referred to as “nature’s engineers,” thanks to their dam and lodge building skills, Dill said the bucktoothed critters do a great deal of good for woodland ecosystems.
“There is constant change with the comings and goings of beavers in and out of an area,” he said. “They are responsible for creating large patchworks of wetland habitats that benefit a whole host of other wildlife and they are a really important part of the ecosystem.”
That sort of ecosystem design can be an upside for landowners, according to Shawn Haskell, Maine Inland Fisheries and Wildlife regional biologist based in Ashland.
Haskell said he and fellow biologists have spent some time recently in the field looking for the Rusty Blackbird (Euphagus carolinus), which has experienced a population decline in recent years and is not all that common in Maine.
“This bird likes really thick stands of young spruce near wetlands where they can forage,” Haskell said. “That is a really unique habitat and invariably when you find it it’s an old beaver flow [and] the beavers could be long gone but they have created that perfect habitat for the rusty blackbirds.”
That can be a real boon for property owners, Haskell said.
“As a landowner, you might say, ‘jeez, they just flooded 10 acres of my land and that means I have lost a bunch of trees,’” Haskell said. “But I’ll tell you what, for that landowner that does not mind, they now have have something special and different [with] blackbird habitat.”
Creating a nuisance
Overall, Dill said, beavers tend to be good neighbors until they decide to help themselves to an ornamental tree buffett.
“If they are causing harm it’s usually because they are doing one of two things — eating the prized ornamental trees someone took the time to plant or causing flooding,” Dill said. “But if they are just swimming around and minding their own business they can be a joy to watch and really interesting to observe.”
If the beavers overstay their welcome, landowners do have some options.
Dill suggests wrapping the trees’ trunk with galvanized metal fencing or chicken wire to prevent the beavers from chewing the bark.
He said there are also chemical deterrents on the market, but the success of those products is somewhat debatable.
Larger landowners, like paper companies, often call in help when beavers block culverts which then overflow and wash out roads. Haskell said.
“Some people just want the beavers gone from their property,” Haskell said. “At IF&W we have [animal damage control] agents who we train and license to trap and remove the beavers.”
The state will also issue special permits for landowners to shoot nuisance beavers, Haskell said.
There are occasions, Haskell said, when what is a welcome wildlife guest for one landowner is a nuisance to the abutting landowner.
“Basically we work with the neighbors to solve any issues and we are lucky in Maine in that in cases where one person wants the beaver but a neighbor wants it gone, they work it out,” Haskell said.
“It’s important to consider your neighbors,” Dill said. “Especially with streams, because if the beaver builds a dam on your land, it can create flooding on someone else’s property.”
Flooding became a major issue for the town of Orrington in 2012 when a beaver dam on private property burst and washed out a public road, causing $125,000 in damages and sparking a lawsuit between the town and the landowners.
Quiet neighbors
Beavers are quiet animals that tend to keep to themselves, but Dill said if you know what to look for, you can determine if one or more has moved into a pond.
“You may see some debris and wood floating around your pond,” he said. “If you see significant damage and chewing on a tree about 6- to 8-inches off the ground, that is a good indication they are around.”
In addition to construction dams across moving water like streams or rivers, beavers construct domed-shaped “lodges” out of tree limbs, sticks and mud for their homes.
Beavers eat the tree bark and seem to be most fond of popals within 100 feet or so of their lodge.
“Of course, their favorite is going to be any tree you just planted,” Dill said with a laugh.
Beavers are not considered dangerous, though they will become aggressive if cornered or otherwise threatened.
The beavers’ main defense seems to be the characteristic “tail slap” in which the animal loudly smacks the surface of the water with its wide, flat tail sending up a spray of water before it dives beneath the surface.
“That seems to be a ‘distraction’ tool the beavers use to frighten the perceived threat and to warn other beavers there is danger nearby,” Dill said.
Some health risks
The biggest risk to a resident beaver population, Dill said, is the fact they carry and pass along the parasite responsible for spreading giardia which can infect humans and other animals with abdominal cramps, nausea and diarrhea.
“It’s sometimes called ‘beaver fever,” Dill said. “You have to drink water containing the parasite to become infected, but if there are beavers in your pond and you go swimming, there is always the risk of getting water in your mouth.”
Love them or hate them, Haskell said it is impossible not to admire their work ethic and construction skills.
“My wife and I spent a good part of a Sunday recently pulling apart one of their dams,” Haskell said. “We pulled out rocks, sticks, mud and logs — it is amazing what they can do.”
