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South Texas Salt Lakes

Site Facts

Country, State, Province/Region:

United States, Texas

Relative Location:

40 km northeast of McAllen; part of the Lower Rio Grande Valley National Wildlife Refuge

Latitude/Longitude:

26 32' N, 98 3' 23'' W

Category:

International

Basis for Designation:

More than 10% of the global population of Long-billed Curlew uses the site.

Size:

733 hectares (1,811 acres)

Joined:

April 2004

Site Owner/Steward:

U.S. Fish and Wildlife Service

Site Partners:

Valley Nature Center

Human Population within 100 km:

106,000

Contact:

Mitch Sternberg
Wildlife Biologist
Lower Rio Grande Valley National Wildlife Refuge
Mitch_Sternberg@fws.gov

 

Description

South Texas Salt Lakes is a WHSRN site consisting of two inland saline lakes surrounded by Tamaulipan thornscrub and grasslands in southern Texas. Both lakes, La Sal del Rey and East Lake (La Sal Blanca), are part of the Lower Rio Grande Valley National Wildlife Refuge that runs along the U.S.-Mexican border. In addition, part of East Lake extends onto private lands.

Surveys have shown that 10% of the estimated global population of Long-Billed Curlews use these lakes as roosting sites during winter months. Biologists and volunteers have counted as many as 2,261 Long-billed Curlews on the lakes at one time out of a total population of an estimated 20,000. Long-billed Curlew, the largest shorebird in North America, is identified in the U.S. Shorebird Conservation Plan as being a highly imperiled species. For more information about this grassland species, you can download the its conservation plan on the Species Conservation Plan page.

South Texas Salt Lakes is one of five WHSRN Sites in Texas (all of International Importance and listed north to south): Anahuac, Bolivar Flats, Texas Mid-Coast NWR Complex, South Texas Salt Lakes, and Laguna Madre - a binational site with Tamaulipas, Mexico.

Ecology & Conservation

The management priorities are to protect and provide habitat for migrating, wintering and nesting birds; to provide public use opportunities; and to continue to minimize disturbance.

Research priorities include investigating the relationship of water levels, salinity levels and the food base (brine shrimp and other invertebrates) and researching the role of artesian wells in species diversity. The impact of commercial brine extraction at La Sal del Rey is a research priority. Research on Snowy Plover nesting success is underway.

Both lakes are under refuge management. The management priorities include maintaining these lakes for migrating, wintering, and nesting birds and providing public use opportunities. This is accomplished by erecting fencing, restricting access during breeding, mitigating oil and gas company activities, erecting signage, and issuing special use permits for birding tour groups.

At East Lake, anti-predator fencing is erected to protect colonies of nesting Gull-billed Terns. Least Terns and Snowy Plover also nest there. Access to the lake is minimized during the nesting season.

At La Sal del Rey, Black-necked Stilt, Killdeer, Snowy Plover, and Least Tern nest. Access is also restricted here during the breeding season. An interpretive tour is led by refuge volunteers to this area during the winter months.

The site is of critical importance to other avian species. Specifically, it is a migration stopover point for thousands of Wilson's Phalaropes and Eared Grebes. Hundreds of these birds spend the winter on the lakes, as well. During the winter, hundreds of Sandhill Cranes and Snow Geese often use the lakes for roosting spots.

The lakes were surveyed for shorebirds, waterfowl, gulls and terns weekly or biweekly from 9/25/01 until 2/25/04. Avian production was monitored and quantified in 2002 and 2003. Surveys of nesting shorebirds were completed in 1996, 2002 and 2003 at La Sal del Rey and East Lake. Researchers from Mississippi State University will be completing a second season studying nesting Snowy Plovers in 2004.

 

Contact

Mitch Sternberg
Wildlife Biologist
Lower Rio Grande Valley National Wildlife Refuge
Mitch_Sternberg@fws.gov

Website: Lower Rio Grande Valley NWR
 

Additional Resources

Status Assessment and Conservation Action Plan for the Long-billed Curlew (Numenius americanus)
Published by the USFWS

Dugger, B. D., and K. M. Dugger. 2002. Long-billed Curlew (Numenius americanus). In The Birds of North America, No. 628 (A. Poole and F. Gill, eds.). The Birds of North America, Inc., Philadelphia, PA.

Books on the history of the Salt Lakes:

Hawkins, Wallace. El Sal del Rey. 1947. Texas State Historical Association, Austin.

Macmanus, F. E. 1885. La Sal del Rey, or the King's Salt: The Celebrated Texas Salt Lake. Brownsville, Texas.

The Handbook of Texas Online also provides a succinct history of La Sal del Rey.