Exploring Cypress Grove

Shorebirds, Waterbirds, and Conservation Science with Nils Warnock and Kenneth Hillan

Cypress Grove, Marshall CA / provided by Nils Warnock

Tucked away on the eastern shores of Tomales Bay, Audubon Canyon Ranch’s Cypress Grove Research Center is a hidden gem in the world of bird conservation. Normally closed to the public, this 100-acre preserve is a sanctuary for shorebirds, waterbirds, and other avian species, offering a unique blend of scientific research and ecological beauty. For those lucky enough to visit, Cypress Grove provides a rare opportunity to witness conservation science in action while being surrounded by stunning coastal landscapes and bird species.

A Sanctuary for Shorebirds and Waterbirds

Tomales Bay is a critical stopover site along the Pacific Flyway and has long been recognized as an important wetland area for wintering shorebirds. However, in the last 30 years, shorebird populations there have declined significantly—from nearly 16,000 individuals in 1989 to approximately 5,300 today, a 66% decline. Among the hardest-hit species has been our familiar Dunlin, a small Arctic-breeding shorebird that has seen dramatic reductions in its wintering populations in California.

A Personal Encounter with Shorebird Conservation

In August 2023, I had the privilege of spending a misty morning surveying shorebirds on Tomales Bay with Nils Warnock (Director of Conservation Science at Audubon Canyon Ranch). It’s also when I had my first-ever sighting of an American Golden-Plover. This remarkable bird had stopped briefly to feed on the shores of Tomales Bay while enroute from its breeding grounds in northern Canada and Alaska to its wintering grounds on the grasslands of southern South America; a staggering migration spanning up to 20,000 miles each year! 

Yet, the American Golden-Plover’s presence was also a reminder of its tenuous history. Nearly wiped out in the 19th century by market hunting, the species has since made a partial recovery thanks to the protections offered by actions such as the 1918 Migratory Bird Treaty Act. 

Witnessing this resilient traveler first hand solidified my ongoing commitment to shorebird conservation. If we are to protect these extraordinary bird species, each with its own unique life history, we need longitudinal data—gathered through monitoring and research—to take informed actions to ensure their survival.

Nils and David Lumpkin banding a short-billed dowitcher at the Walker Creek Delta in Tomales Bay / S. Jennings)

Tracking Dunlin: Motus Wildlife Tracking System

One exciting advance in shorebird conservation at Cypress Grove was the introduction of the Motus Wildlife Tracking System, which helps us to understand the status and movement of species like Dunlin. This technology uses automated radio telemetry to track the movements of tagged birds, offering invaluable data on their migration patterns and habitat use.

Over the past three winters, researchers at Audubon Canyon Ranch and their partners have trapped and tagged Dunlin to study how environmental factors influence their movements. By tracking individual birds, scientists have learned that stormy conditions lead many Dunlins to relocate from Tomales Bay to the Central Valley in search of alternative feeding and roosting sites. These insights are helping us to better understand the factors driving population change and, by sharing and integrating data from different locations, how best to support a species across its entire range.

Dunlin / provided by Nils Warnock

A Rare and Meaningful Experience

During the Birdathon Cypress Grove adventure tour, participants will have the opportunity to explore Cypress Grove in the company of Nils.  As a leading shorebird expert, Nils will share his passion and insights into the behaviors, adaptations, and conservation challenges facing these species. 

For those passionate about birds and habitat preservation, Cypress Grove represents more than just a beautiful landscape—it’s a beacon of hope for the future of migratory birds. With initiatives like Motus and dedicated scientists leading the way, this vital research center continues to play a key role in monitoring and protecting the Pacific Flyway’s rich avian diversity for generations to come.

NOTE: To see all of our 2025 Birdathon Adventure Tours including “Cypress Grove on Tomales Bay”, head over to our Birdathon Trips page here, and register starting Friday, February 28 at 1pm.

Kenneth Hillan, originally from Scotland, graduated in medicine from the University of Glasgow before making the Bay Area his home. A fervent advocate for our winged companions, he is passionate about working with others to create a world where birds and humans can flourish together. Kenneth is a graduate of the 2022 Golden Gate Bird Alliance & California Academy of Sciences master birding class and is currently a block leader for the Marin County Breeding Bird Atlas 2 project.