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Beaver

Beaver mother and kits
Beaver lodge, Sac-San Joaquin Delta
Beaver swimming in water
Beaver dam at GCWA

The North American Beaver (Castor canadensis) is both an ecosystem engineer, helping to create and maintain diverse habitat throughout the State, and a keystone species, filling a critically important role in maintaining the ecosystem for the other species that depend on it. In 2023, CDFW established a Beaver Restoration Program that strives to partner with tribes, non-governmental organizations, private landowners, and other state, federal, and local agencies to implement beaver-assisted restoration projects to support ecosystem conservation, habitat restoration, species conservation, and improve climate change, drought, and wildfire resilience throughout California.

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Conservation and Management

The Department supports a comprehensive approach to beaver management in California that is responsive to conservation needs and reported human-beaver conflict, such as property damage (depredation). The conservation and management of this keystone species is supported through the implementation of various nature-based solutionsnature-based solutions(opens in new tab). The Department also strive to provide funding to partners in conservation conducting restoration projects that can benefit the beaver.

Historically, beavers used to live in nearly every stream in North America with an estimated population of 100-200 million. Human exploitation and eradication efforts reduced those populations to approximately 10-15 million beavers today. Learn more!

Science and Research

CDFW continues working to better understand the complex conservation needs of the beaver, a keystone native species. Research is vital to applying an adaptive approach to managing their population in California.

Beaver Biology

Appearance

Beavers (Castor Canadensis) are the largest rodent species in North America. They have thick bodies and large heads with brown fur. Adults weigh up to 40 pounds and measure more than 3 feet in length including tail. Beavers are the only species known to create their own habitat, and have evolved perfectly suited for their environment. 

  • Wide flat scaly tailBrown beaver standing still
  • Webbed back feet
  • Nimble hand-like front feet
  • Long chisel-like incisor teeth
  • Thick, water-proof fur

Diet

Beavers are strict herbivores and they generally prefer grasses, leaves, and aquatic plants such as cattails, bulrushes, and water lilies. In the fall and winter, they feed primarily on the bark and cambium of shrubs and trees such as aspen, cottonwood, willow and alder. Beavers sometimes consume agricultural crops, and in some cases may travel 100 yards or more from a body of water to reach corn fields, soybean fields, and other crops. In these cases, they generally cut the plants off at ground level and drag them back to the water.

Reproduction

Beavers are monogamous and mate for life. Females reach sexual maturity at 1.5 to 3 years of age and will typically birth 1-4 or more kits per year, depending on habitat quality and food availability. Beavers typically breed only once a year during the winter months. Females give birth to kits in late spring (Baker and Hill 2003).

Beavers live in family units consisting of one adult breeding pair, their young of the year, and young from the previous year. Offspring may remain with the family unit for more than 2 years if habitat quality is poor or population levels reach carrying capacity.

Beaver Behavior

Beavers are generally nocturnal. However, it is not uncommon to see them during the day in larger water bodies. Beavers generally avoid people and do not stray far from the relative safety of water.

  • Beavers need water deep enough to swim to their food sources and avoid predators. beaver grooming tail
  • They build dams and lodges of woody material, dig canals and plug culverts to increase the depth and area of suitable habitat.
  • This woody material is gathered from the ground locally or from small and medium-sized trees that the beavers fell with their specialized teeth.

Beavers do not hibernate. When the water surface freezes in the winter, beavers eat bark and stems from a food “cache” they have anchored to the bottom of the waterway for the winter. They will also swim under the ice to retrieve roots and stems of aquatic plants.

Habitat

Beavers are commonly known for their ability to build dams and change waterways – but the ecosystem benefits provided to other native species in the process may be less recognized. Through the process of ecosystem engineering, beavers can expand wetland, riparian, and wet meadow habitats and increase wildfire resiliency in areas with known beaver activity. Specifically, beavers can:

  • Improve water quality and control water downstream
  • Repair eroded channels
  • Reconnect streams to their floodplains
  • Provide perennial flow to streams that would otherwise run dry 
  • Create beneficial habitats as refugia to drought, wildfire, and climate change

In areas with known beaver activity, there can also be significant increase in biodiversity. Deer and elk frequent beaver ponds to forage on shrubby plants that grow where beavers cut down trees. Weasels, raccoons, and heron hunt frogs and other prey along the marshy edges of beaver ponds. Sensitive species such as Red-legged, Yellow-legged and Cascade frogs, Sage Grouse, and Willow Flycatchers benefit from habitat created by beaver wetlands. In coastal rivers and streams, Coho salmon can benefit from beaver dams by finding protection from high flows and predators until they are big enough to go out to sea.

Range

Beavers were once one of the most widely distributed mammals in North America. However, by the late 1800s beavers were eliminated from much of their range due to unregulated trapping for the fur trade. In California, beaver populations were further impacted during the 1900s by habitat loss and human-wildlife conflict. With the growing recognition of the beaver’s role in ecosystem restoration and conservation and CDFW’s budding beaver restoration objectives, a better understanding of the current and historic range of Northa American beavers in California is needed. As such, the Beaver Restoration Program (BRP) is undertaking an effort to compile North American beaver (Castor canadensis) presence data from throughout the state to update CDFW’s current distribution and range maps for beavers in California.

No comprehensive beaver population survey has been conducted in California. As such, the map below represents the current known distribution of beavers in California according to the best data currently available to CDFW.

To help improve this dataset and our understanding of the current distribution and range of beavers in California, the BRP is requesting submissions of additional beaver observation data. If you would like to submit a beaver observation (including their dams and lodges) and contribute to this mapping effort, please report your observation through CDFW's California Beaver Observation Survey.

View larger map

Potential Conflict and Depredation

While the ecosystem services provided by beavers are increasingly valued in California, beavers can cause problems or damage to property at times. There are proven effective exclusion methods to mitigate human-beaver conflict and prevent damage due to beaver activity. For more information or to report beaver damage, visit the Human-Wildlife Conflict Program page.

Protecting Trees and Plants

Protective fencing, Beaver Institute

Permanent exclusion and/or deterrents can be effective if selectively deployed to protect trees and shrubs, garden plots or agricultural crops.

  • Install low fence (3 feet) constructed of woven or welded wire mesh. Fence should be well-anchored to the ground, so that beavers do not crush, crawl under, or walk over it.
  • Install electric wire 4-6” above the ground.
  • Encircle tree trunks with hardware cloth, sheet metal, or welded wire mesh (2” x 4”).
  • Paint tree trunks with a sand and paint mixture to prevent beaver gnawing. Sand/paint ratio should be approximately 8 ounces (2/3 cup) of fine sand to one quart exterior latex paint.

Preventing Flooding

Install flow device, beaver deceiver

Beavers are attracted to the sound of running water and will seek to plug most culverts or pipes with the goal of creating more or maintaining pond habitat. Additionally, beavers will repair most dam breaches and plug most culverts and pipes that are installed in order to drain the ponds. However, a variety of devices have been developed for controlling beaver impoundments and keeping blocked culverts open. These deterrents (also referred to as coexistence devices) allow landowners to control the water level in beaver ponds, minimize or eliminate the running water sound that triggers their instinct to plug and repair, and mitigate beaver damming efforts without the beavers being aware of their presence. Learn more about three of these devices:

Additional Resources to Prevent Potential Conflicts

Financial Assistance

Financial Assistance Opportunities for Implementation of Non-Lethal Beaver Damage Deterrents
Program Source Eligible Entities or Land Use Types Description Resources
Wetlands and Mountain Meadows Restoration Grants (Nature-Based Solutions) CDFW Government Agencies (Fed/State/Local), Tribes, Non-Governmental Organizations The Beaver Conflict Resolution Grant Opportunity is a new funding opportunity supporting implementation and promotion of human-beaver coexistence strategies (i.e., non-lethal beaver damage deterrence). How to Apply

General Grant Guidelines (PDF)
Partners for Fish and Wildlife USFWS Private and Public Lands Provides technical and financial assistance to landowners interested in restoring and enhancing wildlife habitat on their land. How to Apply
Coastal Program - FY 23 USFWS Private and Public Lands Provides technical and financial assistance through cooperative agreements to coastal communities, conservation partners, and landowners to restore and protect fish and wildlife habitat on public and private lands. How to Apply
Environmental Quality Incentive Program (EQIP) NRCS Agricultural Lands The Environmental Quality Incentive Program (EQIP) is NRCS’ conservation program that helps farmers, ranchers, and forest landowners integrate conservation into working lands. How to Apply
EQIP Conservation Incentive Contract NRCS Agricultural Lands Incentive contracts are an option available through EQIP that offers producers financial assistance to adopt conservation management practices on working landscapes. How to Apply
Conservation Stewardship Program NRCS Agricultural Lands The Conservation Stewardship Program (CSP) helps you build on your existing conservation efforts while strengthening your operation. How to Apply

Beaver Restoration

Over the past decade and throughout the western states a paradigm shift has occurred, with a transition from beavers being viewed primarily as a potential nuisance species to the growing recognition of the vast ecological benefits of beaver activity on the landscape. As a result, there is a rapidly expanding desire among landowners, land managers, restoration practitioners, and other stakeholders in California to utilize beavers for habitat and water management, ecosystem restoration, and increased resiliency to climate change and wildfire. To support the re-establishment of beavers as ecosystem engineers throughout their historical native range in California and facilitate their use in restoring watersheds and ecosystem processes, CDFW has recently created a Beaver Restoration Program (BRP).

The overarching goals of the BRP are to improve human-beaver coexistence, gather a comprehensive understanding of where, when, and how beavers can be utilized to restore ecosystem processes and habitats in California, communicate those findings in clear and meaningful ways, and with that knowledge, effectively utilize beavers as a tool (i.e., nature-based solution) in restoring and conserving habitats and watersheds in California.

For more information about the newly created Beaver Restoration Program, CDFW hosted an informational webinar on Thursday, May 25, 2023. The meeting provided a broad overview of CDFW’s Beaver Restoration Program, including its purpose, objectives, tasks, and timelines. Additionally, the meeting addressed the implementation of pilot and future beaver translocation projects, development of a beaver co-existence toolkit, and policy updates, and concluded with a question and answer session. Future public workshops will be scheduled to discuss human-beaver coexistence strategies and the process for developing and requesting beaver translocation projects.

View a recording of the Beaver Restoration Program Informational Meeting (YouTube Video)(opens in new tab).

Beaver Translocation Projects

The Beaver Restoration Program (BRP) is currently implementing its first two pilot translocation projects with the Maidu Summit Consortium and Tule River Tribe. Moving forward, the BRP anticipates conducting three types of translocation projects: 1) external requests on public and private lands, 2) internal projects on CDFW lands, and 3) CDFW-proposed or -supported, large-scale/multi-landowner collaborations in priority watersheds.

The BRP has now created a process for the submission of external project proposals. To propose a beaver translocation project, landowners, or land managers acting on their behalf, are asked to submit fundamental property and project information using the project proposal form below, and additional information spreadsheet when applicable (e.g., for projects involving multiple collaborating landowners or numerous parcels).

The BRP anticipates a large, initial influx of project proposals; however, given seasonal constraints and the workload associated with the completion of each project, only a finite number of projects can be implemented each year. In 2024, the BRP is conducting a large-scale beaver reintroduction pilot project with the Tule River Tribe and also seeks an additional 1-2 projects for implementation in this calendar year. To reach implementation, all potential projects will require detailed site assessments, ground truthing, and a thorough evaluation of habitat suitability and potentials for conflicts and risks, with each viable project ultimately culminating in a comprehensive capture and translocation plan that is consistent with CDFW’s Conservation Translocation Policy. As such, the BRP will utilize a project prioritization strategy to rank proposals and determine which projects to prioritize for further evaluation and potential implementation each year based on the ecological benefits they have the potential to yield.

Not all project proposals will be deemed viable due to various potential constraints, and others may be high priority but require an extended planning period due to project sensitivities or issues requiring remediation. Projects not selected in the current year, will remain under active consideration for the following year(s). When applicable, the BRP will communicate with applicants regarding:

  • any potential conflicts that would preclude a project from implementation,
  • habitat improvements that may be necessary to support beaver establishment,
  • concerns about potential human-wildlife conflict that requires greater coordination and contingency planning,
  • ecological scenarios that may require an experimental approach, or
  • any other unique circumstances that warrant additional planning and coordination efforts

We encourage any applicants planning to propose a large-scale/watershed-level project to contact the BRP when developing the project proposal. For any other questions about project development, please contact the BRP at BeaverRestoration@wildlife.ca.gov

For clarity, this proposal process is for beaver translocation/restoration projects only; it is not to request that beavers be relocated off a property. Landowners experiencing beaver depredation should submit a report in CDFW’s Wildlife Incident Reporting system(opens in new tab) to receive assistance from their local biologist. The BRP works closely with CDFW staff throughout the state to review depredation issues and identify the most suitable candidate populations for approved translocation projects.

Laws and Regulations

Beavers are classified as a furbearing mammal in California. Below are some, but not all Fish and Game Code (FGC) laws and Title 14 California Code of Regulations (CCR) related to beavers.


Wildlife Health Lab
1701 Nimbus Road Suite D, Rancho Cordova, CA 95670
(916) 358-2790 | WILAB@wildlife.ca.gov