Martinez beavers
A family of North American beavers whose dams helped make urban stream restoration a civic and ecological issue in Martinez, California.
Last updated August 31, 2026
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Overview
The Martinez beavers are a family of North American beavers associated with Alhambra Creek in downtown Martinez, California. They became widely known after a male and female arrived in the creek in late 2006 and established a breeding population in an intensely urban setting. Their presence generated an unusual conflict between flood-management concerns and public support for wildlife conservation, eventually helping turn the creek into a prominent example of urban beaver management and ecosystem restoration. The animals built dams and ponds in Alhambra Creek, including a dam reported to have reached approximately 30 feet in width and six feet in height. Their activity altered the creek from a relatively narrow urban watercourse into a sequence of slower, ponded habitats. The beavers also consumed willows and other vegetation planted during Martinez’s flood-improvement work. Those effects initially raised concerns that the dams could increase flood risk, particularly after the city had invested in a major flood-control project following a 1997 flood. In November 2007, Martinez officials announced that the beavers would be removed because of perceived flooding dangers. At the time, California wildlife rules were understood to restrict relocation, making extermination appear to be the available remedy. Residents, conservationists, merchants, animal advocates, and local organizations objected. The campaign included a public vigil, a rally, intensive media attention, and the creation of Worth a Dam, a local conservation group that advocated non-lethal management. Public pressure led the California Department of Fish and Game to authorize an exception allowing relocation if necessary, while residents continued to argue that the animals should remain and that engineering solutions could control water levels. The city ultimately pursued coexistence rather than eradication. After a city council debate and the formation of a mayoral subcommittee, Martinez hired Skip Lisle of Beaver Deceivers to install a flow-control device. A pipe through the dam regulated the pond’s water level while allowing the beavers to maintain much of their habitat. This approach became the central practical lesson of the Martinez case: infrastructure could be adapted around beaver behavior instead of treating the animals solely as a flood hazard. The ecological effects were substantial. The beaver ponds provided habitat and improved water retention, and wildlife diversity in the watershed increased. Steelhead trout and river otters were reported in 2008, mink in 2009, and additional bird and fish observations followed. The beavers’ role as a keystone species made the site an accessible public example of how one animal can reshape habitat and influence a broader community of organisms. The original female, commonly called “Mom Beaver,” died in 2010 from an infection associated with a broken tooth. A new adult female arrived in 2011, and the population continued to reproduce. Heavy rain that year destroyed the lodge and all four dams, but the beaver presence persisted. By 2014, seven beavers were reported in the creek; a total of 22 had lived there at various times since 2006, with the status of the remainder not fully known. The Martinez beavers also became part of local civic culture. Worth a Dam donated an 81-tile wildlife mural made by schoolchildren, installed on the Escobar Street bridge in 2009. The animals have been celebrated through an annual Beaver Festival held from 2008 onward, and their story has been used to discuss watershed stewardship, humane wildlife policy, flood control, and the ecological importance of beaver engineering. Although they are not a commercial brand or company, the Martinez beavers function as a recognizable local cultural and conservation identity.
History
The Martinez beavers are linked to the broader history of Castor canadensis in California. Before the California fur trade expanded in the late eighteenth and early nineteenth centuries, the Sacramento–San Joaquin River Delta likely supported a very large beaver population. Spanish, French, English, Russian, and American traders harvested beaver and other fur-bearing animals in coastal, inland, and river environments. As coastal fur resources declined, trapping activity shifted toward California’s interior waterways. Between 1826 and 1845, Hudson’s Bay Company parties traveled from the Pacific Northwest through the Sacramento and San Joaquin valleys. Historical accounts describe beaver as abundant around the river mouths and on the delta’s many marshy islands. The commercial fur trade severely reduced beaver populations in many areas, but later conservation and natural recolonization allowed beavers to return to parts of California. The Martinez animals probably originated from or passed through the Sacramento–San Joaquin Delta before settling in Alhambra Creek. The modern Martinez story began in late 2006, when two beavers appeared in the creek. They constructed dams, created ponds, and produced kits. Their habitat engineering collided with the city’s flood-management objectives. Martinez had undertaken a major flood-improvement project after a 1997 flood, and the beavers consumed or damaged some willows and creekside landscaping installed as part of that work. A large dam caused officials to worry that water could back up into downtown areas. The city’s 2007 proposal to exterminate the beavers transformed a local wildlife-management question into a public controversy. Residents organized a vigil and rally, and conservationists formed Worth a Dam. Media coverage brought visitors and cameras to downtown Martinez. After the California Department of Fish and Game provided an exception for possible relocation, the city council considered alternatives, including engineered water-level control. Mayor Robert Schroder created a subcommittee, and the city hired Beaver Deceivers to install a flow device. The device used a pipe through the dam to limit pond elevation while preserving the beavers’ ability to remain. The resulting arrangement made Martinez a frequently cited urban beaver-management example. The ponds created deeper and more varied habitat, and several species returned or became more visible, including steelhead trout, river otters, mink, tule perch, green herons, and hooded mergansers. The beavers’ repeated breeding and their ability to rebuild after storm damage reinforced their role as ecosystem engineers. The population experienced ordinary wildlife mortality and environmental setbacks. The original mother died in 2010 from an infection caused by a broken tooth. In 2011, storms destroyed the lodge and dams, but another adult female arrived and reproduced. The population was reported at seven in 2014, with 22 individuals having lived in the creek at different times since the initial arrival. Public recognition became part of the site’s history. Worth a Dam supported educational and artistic activities, including an 81-tile wildlife mural installed on the Escobar Street bridge in 2009. The animals also became associated with Martinez’s annual Beaver Festival, which began in 2008 and was reported as continuing through 2025. The Martinez case is remembered less as a commercial brand than as a civic conservation narrative: a city initially viewed beavers as a flood problem, then adopted technical and community-based methods that enabled coexistence.
- 2014
Population documented at seven
[1]Seven beavers are reported in the creek, with 22 individuals having lived there at different times since 2006.
- 2011
Storms destroy dams and lodge
[1]Heavy rain removes the lodge and four dams, but beaver activity continues afterward.
- 2010
Original female dies
[1]The founding female dies from an infection associated with a broken tooth.
- 2009
Wildlife mural approved
[1]An 81-tile mural made by schoolchildren is installed on the Escobar Street bridge.
- 2008
Flow-control device is installed
[1]A pipe-based system regulates pond levels while allowing the beavers to remain.
- 2008
First Beaver Festival
[1]Martinez begins an annual festival celebrating the beavers and watershed ecology.
- 2008
Steelhead and river otters return
[1]These species are reported in the watershed after the beavers alter creek habitat.
- 2007
City proposes extermination
[1]Officials cite possible flood risk from the beaver dam and announce plans to remove the animals.
- 2007
Public campaign preserves the beavers
[1]Residents and conservationists organize opposition, leading to a wildlife-agency exception and consideration of non-lethal alternatives.
- 2006
Two beavers arrive in Alhambra Creek
[1]A male and female establish themselves in the urban creek and begin building dams and reproducing.
Products and positioning
A locally significant wildlife and urban-restoration identity centered on coexistence between beavers, municipal infrastructure, and watershed ecology.
Marketing campaigns
- 2008Martinez Beaver Festival
Martinez, California
An annual public festival was established to celebrate the beavers, educate residents about watershed ecology, and promote humane urban wildlife management.
Outcome. The festival became a recurring local conservation and civic event, reported as continuing through 2025.
- 2007Worth a Dam beaver-preservation campaign
Martinez, California
Residents and conservationists opposed the city’s proposed extermination of the Alhambra Creek beavers. The campaign used public demonstrations, a vigil, media outreach, and civic advocacy to promote relocation alternatives and continued coexistence.
Outcome. The city abandoned extermination as its practical course and adopted a flow-control solution that allowed the beavers to remain.
Brand decisions
2008
Adopt non-lethal flow managementStrategyBackground
The city needed to control water levels without destroying the beaver habitat that residents and conservationists wanted preserved.
Action taken
Martinez hired Beaver Deceivers to install a pipe through the dam, limiting excessive pond elevation while leaving the beavers in place.
Aftermath
The device was reported to be controlling water levels effectively as of 2013, and the site became an example of urban coexistence with beavers.
2007
City orders proposed removal of the beaversOtherBackground
Officials believed the animals’ dams could increase flooding in downtown Martinez and were concerned about damage to creekside landscaping associated with the city’s flood-improvement work.
Action taken
The city initially announced extermination, while public opposition and wildlife-agency involvement created an opportunity to evaluate relocation and engineering alternatives.
Aftermath
The city ultimately retained the beavers and moved toward engineered flow control rather than eradication.
Recent events
- 2011
Flooding destroys the lodge and dams[1]
Other
Heavy rain washed away the beaver lodge and all four dams in Alhambra Creek, although beaver activity later continued.
- 2011
New adult female joins the creek population[1]
Other
A new adult female arrived in the creek and subsequently produced three young.
- 2010
Mom Beaver dies after infection[1]
Other
The original female beaver died after an infection linked to a broken tooth, according to a necropsy.
- 2009
Martinez approves a wildlife mural[1]
Campaign
The city council approved an 81-tile mural created by schoolchildren and donated by Worth a Dam to commemorate the beavers and other creek wildlife.
- 2008
Flow device installed to manage the beaver pond[1]
Other
The city hired Skip Lisle of Beaver Deceivers to install a pipe-based flow-control system through the dam, allowing water levels to be regulated without removing the beavers.
- 2008
Wildlife returns to Alhambra Creek[1]
Other
Steelhead trout and river otters were reported in the watershed after the beavers’ ponds changed local habitat conditions.
- 2008
Annual Beaver Festival continues in Martinez[1]
Campaign
Martinez began an annual Beaver Festival celebrating the animals, local ecology, and watershed stewardship; the festival is reported to have continued through 2025.
- 2007
Martinez proposes removing the beavers[1]
Other
City officials announced that the beavers should be removed because they believed the dams posed a flooding risk. Public opposition quickly produced rallies, a vigil, and national media attention.
- 2007
Wildlife authorities allow a non-lethal management option[1]
Regulation
Following public pressure, the California Department of Fish and Game granted an exception that permitted relocation if needed, while residents continued pressing for the beavers to remain.
- 2006
Beavers establish a breeding population in Alhambra Creek[1]
Other
A male and female beaver arrived in Martinez’s Alhambra Creek and began building dams and reproducing in the urban watershed.
Sources1 sources
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