Places We Protect

Shamrock Island Preserve

Texas

A massive group of large brown pelicans gather together on a sandy shore that disappears into blue ocean water.
Shamrock Island Preserve Brown pelicans gather at TNC's Shamrock Island Preserve. © Rich Kostecke

Shamrock Island Preserve is an important colonial bird-nesting island on the Texas coast.

Overview

Description

On the eastern shore of Corpus Christi Bay lies one of the most important colonial bird-nesting islands on the Texas Gulf Coast. The island was once an extensive peninsula of Mustang Island, but, in the 1950s, a series of navigational channels were dug into the landmass for oil and gas exploration, significantly weakening it. In early August of 1970, Hurricane Celia's path of destruction completely separated the peninsula into an island, creating a prime rookery nearly free of human disturbance and predatory wildlife. Today, it remains one of the most productive waterbird nesting islands on the Texas coast. Nineteen waterbird species now nest on The Nature Conservancy's (TNC) 110-acre Shamrock Island Preserve each year, some of which have thousands of nesting pairs.

Grasses and shrubs help stabilize Shamrock Island's uplands, while marsh plants occupy areas frequently inundated with high tides. Offshore, seagrass meadows help reduce wave energy and provide essential forage for redhead ducks as well as nursery, feeding and refuge areas for many estuarine fish and invertebrates. On land, resident and migratory species depend on the preserve’s plant communities for nesting sites, food and shelter. Notable plant species of conservation interest include seaside little bluestem, gulfdune crowngrass, sea oats, shoal grass and Texas stonecrop. 

Access

CLOSED TO THE PUBLIC

Size

110 acres

Explore our work in Texas

A bird chick with fuzzy feathers and an open beak.
HATCHED Each year, numerous chicks hatch on Shamrock Island Preserve, like this young Caspian tern. © Rich Kostecke

Why This Place Matters

Shamrock Island Preserve is difficult for predators like coyotes and feral hogs to reach, creating a safe haven where nesting birds can thrive. The island is home to several rare species, among them the state-threatened reddish egret and white-faced ibis. It also hosts one of the largest colonies of nesting brown pelicans on the Texas coast.

The preserve offers high-quality beach habitat for ground-nesting birds such as skimmers and four species of terns, including thousands of pairs of royal terns. Great, little blue and tricolored herons nest on the island too, along with black-crowned night herons, great and snowy egrets and roseate spoonbills.

Photos from Shamrock Island Preserve

Discover the diverse wildlife at this critical colonial bird nesting island.

Three white birds with orange faces and long, slender beaks sit in green vegetation.
A pink feathered bird stands bent over in shallow, calm water with its spoon-like beak in the water.
At least 8 adult brown pelicans stand in the sand on the shore, wading into ocean waters.
Two volunteers crouch near the shore, planting small, green seedlings in the sand.
Two featherless, white baby pelicans huddle together in a nest amongst green vegetation.
Two gray birds with white bellies stare off into the distance as they sit amongst green vegetation.
Two birds with brown bodies, white necks, brown crowns and orange beaks stand on a branch.
Over a dozen small white and black birds with bright orange beaks sit on nests in the sand.
Two white-colored reddish egrets sit at the top of green vegetation against a blue sky.
Five large, brown pelicans sit on low lying branches along the shore.
Five volunteers plant native seedlings on the beach.
RESTORING HABITAT Gulf Corps volunteers plant native species at Shamrock Island Preserve. © R.J. Hinkle

What TNC Is Doing

Conservation efforts have helped make Shamrock Island a leading site for colonial waterbirds, with 27 breakwaters built around it to protect shorelines from excessive wave action. These protective rock walls encourage seagrass habitat establishment behind them, where young seabass and other fish can grow that serve as "fingerling" food for nearby nesting chicks.

Shamrock Island's proximity to Mustang Island—combined with its minimal disturbance—makes it an ideal testing ground for island restoration strategies and much more. For instance, TNC has been tagging and monitoring the impact of predatory crested caracara that nest on the island in a study led by the Harte Research Institute of Texas A&M University-Corpus Christi. The Institute is also modeling whether Shamrock Island will be a top priority for coastal island restoration to support Texas' waterbird populations.

Learn More

Shamrock Island Preserve is always closed to the public. Waters surrounding the island are open to the public for recreation, but we ask that you “Fish, Swim and Play from 50 Yards Away” to give space for waterbirds.

Access to the island is strictly prohibited during the February through September waterbird nesting season, unless prior arrangements are made with TNC. For more information, contact Director of Landscape Initiatives Sonia Nájera (snajera@TNC.ORG).