Beaver Management Information

Living With Beaver

Beavers play an important role in our local ecosystem, creating wetlands that support biodiversity and improve water quality. However, their activity can sometimes lead to challenges for homeowners and public infrastructure. This guide provides essential information for residents and landowners on how to coexist with beavers, prevent conflicts, and maintain a balance between nature and the needs of the community.

Beavers are North America’s largest native rodents, weighing between 35 and 80 pounds as adults. They can be 2–3 feet in length, with an additional 10–18 inches for the tail. Males and females are similar in size. Beavers have dark brown to reddish brown fur. Large, webbed hind feet and a flat, wide leathery tail help them to move swiftly in water. 

Adult beavers have few predators and may live up to 20 years or more. They stay with the same mate for life and breed during winter (January through March). The females give birth to 1–9 kits inside a lodge between April and June. These kits stay with their parents through two winters before dispersing the following spring. A single family unit is called a colony, and is typically made up of 6–8 individuals; two adults, that year’s kits, and the young from the previous year. Pre-colonial populations were estimated at 60 to 400 million individuals in North America. By the early 1900s, the beaver population was as low as 100,000 individuals, and were almost eliminated from Massachusetts.

1. Flood Prevention
Beavers build dams to create ponds, which can sometimes lead to flooding in residential areas, roads, or other infrastructures. Here are some effective ways to manage water levels:

• Beaver Deceiver Devices: These are flow management devices installed in beaver dams or culverts to regulate water levels. By allowing some water to pass through while maintaining the dam, these devices reduce the risk of flooding without harming the beavers.                                                               
  • If you would like to see one of these devices for yourself, you can go to the Duck Pond in the Hop Brook Conservation Land, where these devices have been installed to maintain water levels while still allowing the beavers to thrive.   

• Pond Levelers: A similar solution, pond levelers, can be installed to keep water levels at a safe height, preventing flooding while allowing beavers to continue their natural activities.  

• Breaching and Removing the Dam: Dam breaching is an immediate, but short-term solution to flooding problems caused by beaver. If beaver remain at a site during a dam breach, they will be cued by the sound of escaping water, and will usually rebuild the damaged dam quickly, sometimes overnight. Breaching dam can also cause unintended flooding of your downstream neighbors when not done carefully.

          Permits are needed to disturb a beaver dam or lodge for any reason.

2. Protecting Trees and Shrubs

If your trees or shrubs are being damaged by beavers, constructing an exclosure is one of the best ways to stop beavers. An exclosure is a sort of cage around the trunk of the tree or shrub you wish to protect to prevent the beaver from chewing them.

Proper exclosures should be made of heavy-gauge fencing, at least four feet tall, flush with the ground, and at least 6 inches away from the tree.

Alternatively, non-toxic repellents designed to deter wildlife can be applied to tree trunks, though these are less effective as long-term solutions.

If you need to protect a larger area such as an orchard or nurseries, standard fencing will work as beavers don’t climb well and rarely burrow under fences.

3. Trapping and Regulations

Beaver trapping is regulated by the Massachusetts Division of Fisheries and Wildlife (MassWildlife). If a beaver poses a significant threat to property or public safety, trapping may be considered as a last resort.

• Trapping Season: The regulated beaver trapping season in Massachusetts runs from November 1 to April 15. Only licensed trappers may set traps during this time.                                                                                                        
• Emergency Permits: Outside of the trapping season, property owners experiencing severe beaver-related flooding or property damage can apply for an emergency permit. Contact Sudbury’s Health Department for guidance on the permitting process.

• Humane Considerations: It is essential to remember that beavers are a protected species in Massachusetts. Non-lethal management methods are always preferred where feasible.

If you are considering trapping and/or removing beaver from your property, please review the information provided by Mass Wildlife here. 

4. Public Health Concerns

While beavers generally do not pose a direct threat to humans, there are some public health considerations to keep in mind:

• Giardiasis (Beaver Fever): Beavers can carry a parasite called Giardia, which may contaminate local water sources and cause illness if ingested. Residents should avoid drinking untreated water from ponds or streams and ensure pets do not drink from these sources.
• Mosquito Breeding: Beaver ponds can create stagnant water that may increase mosquito populations. To mitigate this, residents should report significant mosquito issues to the local health department and consider using mosquito repellents and other preventive measures during high mosquito activity months.

Beavers are one of many important species that can assist in insulating our communities from the dangers posed by climate change. They help to create wetland habitat that flourishes with biodiversity and aids in the natural life cycles of forests. For more information about that numerous benefits provided by beavers, you can explore those outlined by the Fish and Wildlife Service.

Coexisting with beavers can be rewarding, as their presence benefits the environment and enhances biodiversity. By taking proactive steps and utilizing available resources, residents can effectively manage beaver activity while minimizing conflicts and supporting Sudbury’s rich natural landscape.

All work in wetlands and wetland buffer zones, including the above beaver management methods, requires permits and approval from the Conservation Commission.

For more information or to report beaver-related concerns, please contact Sudbury’s Conservation Department at concom@sudbury.ma.us or by calling

(978) 440 5470.

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