Consistent with our mission “To conserve and restore natural ecosystems, focusing on birds, other wildlife, and their habitats, for the benefit of humanity and the Earth’s biological diversity” the Marin Audubon Society has been acquiring properties in Marin County with current or restorable habitats. Some properties are restored and turned over to a public agency such as the State Department of Fish and Wildlife or the Marin County Open Space District (MCOSD). Some properties remain in the ownership of the Marin Audubon Society.

In the mid 1980s Marin Audubon Society (MAS)  and Marin Baylands Advocates (MBA) launched the Campaign for Marin Baylands. MBA mapped baylands at risk and began a public education effort to inform decision-makers and the public about the historic loss of baylands to filling and diking, about the environmental values and ongoing threats to remaining baylands. MBA strategizes and raises funds to protect baylands in partnership with Marin Audubon Society, which assumes title to most of the properties. Acquisition of larger properties has been made possible by grants from federal, state and county agencies, private foundations and donations from the public primarily to MBA. Many small parcels have been acquired on tax default sales with funds raised by MBA.

To date MAS has acquired, either through purchase or donation, more than 1,000 acres of Marin County land of which 228 have been transferred to the MCOSD and 362 acres have been transferred to the California Department of Fish and Wildlife. Tidal marsh restoration projects have been completed on five parcels, major enhancement work on and planning for a tidal marsh restoration sea-level rise adaptation project is underway on another parcel.

MAS-Owned Properties

Petaluma Marsh

This 182-acre property is located in Marin County at the Marin-Sonoma County line. The parcel consisted of 82 acres of tidal marsh and 100 acres of diked historic tidal marsh. After negotiating with Sanifill, which has purchased the property from Jordan Smith, (the Smith family established the landfill and operated it for many years) MAS purchased it from Waste Management Inc. with funds from CALFED and Caltrans. The Caltrans funds were mitigation for impacts to tidal marsh resulting from the earthquake retrofitting of the bridge over Sonoma Creek. The Caltrans funds were managed by the Coastal Conservancy.

Petaluma MarshPetaluma Marsh

MAS restored100-acres that had been diked seasonal wetland to tidal marsh and adjacent upland. The 100-restored acres had been leased to the adjacent property owners, the Corda’s, for grazing of dairy cows. With the levees breached, the restored marsh is now connected to art of the Petaluma Marsh, which is the largest saltwater marsh system in the state.


This 632-acre property was purchased by MAS in January of 2003, with funds from the MCOSD, State Coastal Conservancy, Wildlife Conservation Board, CALFED, Marin Community Foundation, Caltrans, Sierra Club, Marin Conservation League, Forrest Lattner Foundation, Bay Institute and private, small foundation donors to the Marin Baylands Fund at the Marin Community Foundation. Title to 361.7 acres of diked bayland was deeded to the Wildlife Conservation Board, and 208 acres of oak woodland was deeded to the MCOSD.  For almost 20 years prior to the acquisition, MAS opposed three different proposals to develop housing on the property. More on Bahia here.


Click on images below for larger view

MAS retained ownership of 61 acres consisting of one +/- acre of former parking lot at the end of Bahia Drive, and 60 acres of upland and filled peninsulas at the end of Topaz that were created as building lots for houses.

The grant MAS received from CALFED included $1.4 million to restore tidal marsh at Bahia on property now owned by the California Department of Fish and Wildlife and on MAS property. The hydrologic engineering firm of PWA prepared the design for the restoration project, which has now been completed. Others on the design team are the Point Reyes Bird Observatory, Peter Baye, Ph, D., Plant Ecologist, and the Watershed Nursery.

The Bahia uplands, now owned by MCOSD are the only known location where blue-oak dominated woodland exists adjacent to salt marsh. This parcel abuts the Rush Creek/Cemetery Preserve also owned by MCOSD and has become part of the Rush Creek Preserve. A public access trail connects the two.

Simmons Slough Wildlife Corridor

The following properties are located within the watershed of Simmons Slough, which is a diked tributary of Novato Creek. Most of the rest of the lands along this slough are in public ownership, which enhances the value of all of the lands as habitat. The exception is 300 Olive Ave., which is the upstream parcel from MAS properties.

Our vision is to protect all of the Simmons Slough Wildlife Corridor i.e.  all or most of the wetlands and adjacent uplands of the watershed. Mission Valley Properties, the Marin County Wildlife and Fisheries Advisory Committee, the Marin Community Foundation, and the Regional Water Quality Control Board have assisted with funding for the acquisition and planning of restoration of these properties. The biological consultants Wetlands and Water Resources designed the enhancement plan described below. And Peter Baye Ph.D. prepared a Vegetation Management plan.

The National Resource Conservation Service (NRCS) purchased and now holds a conservation easement on the Atherton Avenue and Fryer Trust Bayland parcels. With a Wetlands Reserve grant, NRCS funded and MAS implemented the seasonal wetland enhancement project discussed below. The easement requires NRCS staff to visit the properties annually to check on status. Activities on the sites must be approved by NRCS.

Olive Avenue Bayland

This 19-acre property at the southwest corner of Olive and Atherton Avenues, was purchased by MAS in 2000 with funding from the MCOSD and the California Coastal Conservancy, and donors to the Marin Baylands Fund at the Marin Community Foundation. Funding from Towel Brothers removed fill to restore a small section of seasonal wetlands and enhance adjacent uplands by removing invasive plants and installing natives. Title to the property was transferred to the MCOSD in 2010.

Atherton Avenue Bayland

This 84-acre former tidal marsh was purchased in 2002. Funds from the Coastal Conservancy, the MCOSD, and donors to the Marin Baylands Fund at the Marin Community Foundation made the purchase possible. The parcel stretches from Atherton Avenue to Deer Island. The grant from the Wetlands Reserve Program funded enhancement of the diked seasonal wetlands by excavating four areas on this and the Atherton Avenue parcel to lower the elevation of the four  areas so they would pond water for habitat.

Fryer Trust Bayland

This 60-acre property borders Atherton Avenue on its north side, Olive Avenue to the west and the Atherton Avenue Baylands on the east. It was donated to Marin Audubon by the Fryer Trust in 2003, owners of an adjacent property to the south that was developed as the Olive Ridge Housing. A privately owned parcel is at the corner of Olive and Atherton Avenues. Several of the shallow pond areas described above are on this parcel.

Black Point

MAS has acquired many small tax parcels in the Black Point area of Novato on tax default sales or through donations. Marin Baylands Advocates has funded most of the purchases. About 100 years ago, the Black Point area was subdivided into tiny parcels  (5 x 25 feet) that were awarded as prizes for subscriptions to newspaper or magazine. Levees were constructed along the tidal marsh edge.

Currently MAS owns 20 parcels. More were purchased but, where possible, some have been combined to reduce parcel taxes. Acquired parcels are either historic tidal marsh now seasonal wetlands or adjacent uplands.

The largest number of MAS-owned Black Point parcels are associated with Norton Pond and include all parcels along the pond south edge except one. Other parcels are scattered about the seasonal wetland area and some are adjacent uplands. MAS anticipates that there will be enough adjacent parcels to undertake a habitat restoration.

Arroyo San Jose

In 2006 MAS acquired two tax default parcels on the Arroyo San Jose in Novato, off of Bel Marin Keys Blvd. These parcels are within a light industrial area and consist of riparian vegetation habitat with old Valley Oak trees.

Tiscornia Marsh

This 20 acre parcel located just east of San Rafael’s Albert J. Boro Community Center was generously donated to MAS by Mary Tiscornia in 2008. This parcel consists of an unimproved levee, cordgrass marsh and submerged open water. California Ridgway’s Rails and Black Rails have been observed.

MAS was awarded a MCF grant which funded development of  a conceptual tidal marsh restoration nature based sea level rise adaptation project. In 2019, a Measure AA grant was awarded from the San Francisco Bay  Restoration Authority funded development of a conceptual plan and CEQA review on the MAS property along with the adjacent diked marsh. The conceptual plan is being prepared by Environmental Science Associates to restore tidal marsh and open the adjacent diked marsh owned by the city of San Rafael to  tidal action; improve the levee which will protect the Canal Area/San Rafael; and provide transitional habitat that will benefit the California Ridgway’s  Rail and other species. The  Bay Trail will  be constructed on the levee. 

For more information visit the Tiscornia Marsh Nature Based Sea Level Restoration Project website.

Murphy’s Rock

This property consists of two underwater lots totaling 34 acres  that were donated to MAS in 1978. The parcels are located along the San Rafael shoreline just off the Jean and John Starkweather Shoreline Park near the Spinnaker Wetland and Canalways.

Corte Madera Ecological Reserve Marsh Restoration

After more than 30 years opposing office and housing and other developments and negotiating with the property owner, Frank Green, he finally gave up and agreed to sell the five-acres to Marin Audubon. Funding for the purchase came from the Coastal Conservancy, the Wildlife Conservation Board, Marin County Open Space District, Marin Baylands Advocates, Audubon California, the Marin County Fish and Wildlife Commission, California Alpine Club Foundation, the RHE Foundation and Greenway Boardwalk neighbors.

The property was almost entirely filled tidal marsh on which patches of seasonal wetlands had developed.  Fill consisting of construction debris was deposited in the 1950’s by Holtzinger builders. Later the property owner, installed a drainage system and surcharge in anticipation of developing.

The importance of the marsh stems from its location, bounded on three sides by the California Department of Fish and Wildlife’s Corte Madera Ecological Reserve. On the south boundary is the Heerdt Marsh, a tidal marsh that has never been diked, on the east filled land of the Reserve and on the north the Reserve’s parking lot.

The Reserve historic tidal marsh is habitat for a large population of the endangered Ridgway’s rails in addition to shorebirds and waterfowl. The fill destroyed tidal marsh habitat and the remaining marsh habitat was further degraded by walkers, kite boarders, bicyclists and dog walkers many off leash and some running through the marshes. The subsequent restoration was designed to remove these impacts and restore viable habitat.

Corte Madera marshCorte Madera marsh

Triangle Marsh

This 31-acre property, acquired in 1999, is located on Paradise Drive across from the Ring Mountain Preserve in Corte Madera. The property consisted of ancient tidal marsh (habitat for the endangered California Ridgeway’s Rail), intertidal baylands (habitat for migratory waterfowl and shorebirds), and uplands, most  of which was created by the placement of fill when Paradise Drive was constructed. The owner had purchased the property in the 1970s when Marin Audubon Society and the Town of Corte Madera were raising funds to purchase it.  He proposed several housing developments that were denied by the Town through the years, before finally agreeing to sell to Marin Audubon.

Funding for the purchase came from a variety of sources including the State Coastal Conservancy, Marin County Open Space District (MCOSD), North American Wetlands Conservation Council (NAWCA), the J. M. Long Foundation, U.S. Fish and Wildlife Service’s San Francisco Bay Program, Marin County Wildlife and Fisheries Advisory Committee, the San Francisco Bay Keeper, an anonymous-major donor and Marin Baylands Advocates through donors it raised and were deposited in the Marin Baylands Fund at the Marin Community Foundation. Funding for the restoration was provided by the Marin Community Foundation, San Quentin Prison as mitigation for impacts of the shoreline stabilization project at the prison, and Caltrans as mitigation for impacts to Corte Madera Creek for the HOV lane.

San Clemente Creek Tidelines

In 2005, MAS acquired a 4.34-acre tax default property adjacent to Triangle marsh. This parcel is underwater and expanded the Triangle Marsh parcel to 35 acres. The parcel is at mouth of San Clemente Creek Corte Madera.

End of Channel, Corte Madera

This site was purchased on a tax default sale in 1999. It is located at the end of Channel Drive in Corte Madera, is approximately one acre and consists of uplands, much of which is the trail entering the Corte Madera Ecological Reserve at its south end, and tidal marshes of San Clemente Creek. Donations from our members were the primary source of funds.


A single small parcel of seasonal wetlands was donated in 2013. The parcel is a single parcel within this approximately five-acre pocket of historic tidal marsh. Tidal action to this flat, low-lying area  was cut off by Highway 101. The area is in unincorporated San Rafael.

Arroyo De Corte Madera Del Presidio

This 2.44-acre parcel was acquired in 2008. It consists of a strip of shoreline along the shoreline of The Redwoods in Mill Valley at the westerly end of Bothin Marsh in Richardson Bay. The parcel contains saltwater (tidal creek) and shoreline habitat.


Easements Held By Marin Audubon Society

BAHIA – This easement is on a strip of shoreline at the end of Albatross.  The parcel was originally part of the acquisition parcels, however, the adjacent property negotiated with the then Bahia property owner to take title to the property and we ended up with an easement

SIMMONS SLOUGH – This easement consists of two parcels, strips of land along banks of the Olive Ridge Housing development adjacent to the south of our /Simmons Slough property. The sloped parcel was created by placement of fill for the housing development The purpose of the easement is to ensure the slope remains habitat populated with native plants, and does not become part of the backyards of adjacent neighbors.