Clive Runnells Family Mad Island Marsh Preserve
Mad Island Marsh Clive Runnells Family Mad Island Marsh Preserve © Ian Shive

Places We Protect

Clive Runnells Family Mad Island Marsh


Clive Runnells Family Mad Island Marsh Preserve is part of an expansive coastal wetlands system.

The Clive Runnells Family Mad Island Marsh Preserve is a nature lover’s dream. Its lush coastal prairies, freshwater wetlands and salt marsh habitats are home to a vast array of wildlife, from alligators to armadillos. Preserving the natural function of this region—and the organisms that depend on it for survival—safeguards an important slice of Texas’ natural history and heritage.


Over 75 years ago, an expansive coastal prairie and wetland system stretched nearly unbroken across nine million acres in Texas and Louisiana. After decades of overuse and development, only two percent of this landscape endures today. Comprising a key portion of this remaining habitat, Mad Island Marsh Preserve supports a diversity of marine life and wildlife—from red drum, blue crabs, brown shrimp, southern flounder and speckled trout to bobcats, rattlesnakes, white-tailed deer and coyotes.

The preserve is also known as one of the “birdiest” locations in North America. Sitting at the confluence of the Mississippi and Central Flyways—two of four principal North American migratory bird routes—its prairie and wetland habitat serves as a critical stopover for thousands of migratory birds to rest and refuel after traversing hundreds of miles nonstop across the Gulf of Mexico. To study the patterns and behavior of these birds, the Smithsonian Migratory Bird Center operates a bird banding station on Mad Island Marsh Preserve each spring. Additionally, the preserve’s annual Matagorda County-Mad Island Marsh Christmas Bird Count is one of the most prominent Audubon Christmas bird counts throughout the country, ranking first in number of species tallied for over a decade.


Establishment of the Clive Runnells Family Mad Island Marsh Preserve dates back to 1989, when Clive Runnells II donated 3,148 acres of coastal wetlands and upland prairies to TNC. The land is directly adjacent to the Texas Parks and Wildlife Department’s Mad Island Wildlife Management Area, which TNC helped establish with a 5,700-acre donation to the Texas Parks and Wildlife Department. In 1993, TNC added 3,900 acres to Mad Island, with critical support from the North American Wetlands Conservation Council, as well as the National Fish and Wildlife Foundation, Dow Chemical, US Environmental Protection Agency, Trull Foundation and Communities Foundation of Texas.

Today, TNC’s primary goal is to boost resilience and connectivity within the Gulf Coast Prairies and Marsh ecoregion. Using tools offered up by nature itself—including prescribed fire, invasive species control, native seed harvesting and planting and more—we’re working to preserve and restore this unique and historic Texas ecosystem for nature lovers everywhere.


The Clive Runnells Family Mad Island Marsh Preserve offers monthly birding tours on the third Friday of each month. Feathered Fridays events offer visitors a unique opportunity to birdwatch while exploring this rich preserve. For a list of other open days and further information, visit our Events page.

Visitation is open for volunteer workdays, monthly Feathered Friday birding tours and various special events throughout the calendar year. An appointment is needed for visits outside of these organized events. For more information, contact Steven Goertz, Preserve Manager.