Places We Protect

Clive Runnells Family Mad Island Marsh


An expanse of dense coastal wetlands intermixed with open water along the Texas Gulf Coast at sunset; the sky is orange.
Mad Island Marsh Wetlands on Matagorda Bay at the Clive Runnells Family Mad Island Marsh Preserve. © Jacqueline Ferrato

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



The coastal prairie, freshwater wetlands and salt marshes that comprise The Nature Conservancy's (TNC) Clive Runnells Family Mad Island Marsh Preserve are in dynamic and continuous flux. The landscape is dotted with slow-draining natural depressions, providing ephemeral wetlands for a rich variety of wildlife species.

Maintaining the delicate balance of this region’s natural function protects a critical ecosystem threatened by development and overuse and enhances its resilience to extreme weather, fragmentation and human degradation. 


Limited Access

Visitation is by appointment only outside of scheduled events/volunteer opportunities


Bird and wildlife watching, hiking


7,063 acres

Explore our work in Texas

Explore the Preserve

Watch this clip of Mad Island Marsh Preserve captured through drone footage.

VIEW FROM THE TOP Explore the Clive Runnells Family Mad Island Marsh Preserve and Matagorda Bay via drone. © Jacqueline Ferrato
Closeup of a researcher's hands as he releases a bird.
Bird Banding A researcher releases a sedge wren after banding it at Mad Island Marsh Preserve. © Jacqueline Ferrato/TNC

Why This Place Matters

More than 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 2% endures today. This makes Mad Island Marsh Preserve an important piece of a broad network of coastal conservation lands along the Gulf Coast. Its continuum of habitat helps reduce erosion and contributes to the overall health of Matagorda Bay, which meets with the Gulf of Mexico, improving resilience for marine life, endemic plants, wildlife and coastal communities.

Situated at the confluence of two principal North American migratory bird routes, the preserve also provides nesting, feeding, resting and roosting habitat for more than 250 species of birds. Notable species include the endangered whooping crane, the rare Le Conte’s sparrow and more than 20 species of waterfowl. For years, the Smithsonian Migratory Bird Center has operated a bird banding station on the preserve to study the patterns and behavior of migratory birds. Additionally, the 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 more than a decade. Other wildlife species found on the preserve include everything from red drum, blue crabs, brown shrimp, southern flounder and speckled trout to bobcats, rattlesnakes, white-tailed deer and coyotes. 

Photos from Mad Island Marsh Preserve

Discover the diverse plant life and wildlife in this expansive system of coastal prairies and wetlands.

A black-necked stilt wades through wetlands at Mad Island Marsh Preserve.
Six fire practioners from the Texas Chapter conduct a prescribed burn on coastal prairie at Mad Island Marsh Preserve.
An adult and several young American Alligators rest among vegetation on the banks of Mad Island Marsh Preserve wetlands.
A field of prairie grasses with purple flowers sways in the wind.
A tricolored heron soars along wetlands at Mad Island Marsh Preserve.
A bobcat crouches and hides within browning coastal prairie grasses.
A white-tailed deer stands frozen in place along a gravel trail at Mad Island Marsh Preserve.
Nearly thirty bird enthusiasts gather together and pose for a group photo at the Mad Island Marsh Preserve, following a birdwatching tour.
Two adult buff-breasted sandpipers walk through muddy wetlands at Mad Island Marsh Preserve.
A slough, or shallow lake channel, along the northeast boundary of the Mad Island Marsh Preserve extends as far as the eye can see, surrounded by thick, green wetland plants.
TNC volunteers collect seeds from flowering forbs.
Harvesting Native Seed Volunteers and TNC Texas staff help collect basket flower seeds at Mad Island Marsh Preserve. © Kenny Braun

What TNC Is Doing

The establishment of the Clive Runnells Family Mad Island Marsh Preserve dates back to 1989, when Clive Runnells II donated more than 3,000 acres of coastal wetlands and upland prairies to TNC. The land is directly adjacent to Texas Parks and Wildlife Department’s Mad Island Wildlife Management Area, which TNC helped establish with a 5,700-acre donation. In 1993, TNC added 3,900 acres to the preserve.

In the 1980s and 1990s, much of our work at Mad Island centered on enhancing the freshwater wetlands and coastal marshes for wintering waterfowl. In close partnership with organizations like Ducks Unlimited and the U.S. Fish and Wildlife Service, we created more than 500 acres of seasonally flooded wetlands that can provide critical stopover and wintering grounds for migrating birds.

Today, we’ve broadened that focus, managing the preserve using prescribed fire, invasive species control, and native seed harvesting and development—with an eye toward supporting this ecosystem’s natural processes to create functioning, connected and resilient communities that support the health of the broader Gulf Coast prairies and marsh ecoregion.


  • Visitation is limited to volunteer workdays and various special events throughout the calendar year. An appointment is needed for visits outside of these organized events. For more information, contact preserve manager Steven Goertz (sgoertz@TNC.ORG)

  • The Gulf Coast is home to hundreds of bird species. If you're attending an event or have arranged a visit with our Preserve Manager, bring your binoculars, bird journal, your favorite bird books/guides and a scope. We also recommend good walking shoes that can get wet, a camera with extra film, a water bottle, bug spray and sunscreen.

  • Staff, volunteers and visitors are using community-based science to record wildlife sightings in and around Mad Island Marsh Preserve. To log your findings and see what has been identified nearby, join our iNaturalist or eBird communities.