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Estero Río Colorado

Site Facts

Country, State, Province/Region:

Mexico, Baja California and Sonora

Relative Location:

At the mouth of the Colorado River on the Islas del Golfo, northern end of the Gulf of California

Latitude/Longitude:

30 30' N, 115 10 W

Category:

International

Basis for Designation:

More than 100,000 shorebirds annually.

Size:

240,000 hectares (593,052 acres)

Joined:

December 1992

Site Owner/Steward:

National Commission on Natural Protected Areas (CONANP)

Site Partners:

Pronatura Noroeste, Commission on Ecology and Sustainable Development of Sonora (CEDES), Autonomous University of Baja California Sur, Ensenada Center for Scientific Research and Higher Education (CICESE), University of Arizona

Human Population within 100 km:

300,000

Contact:

Martín Sau Cota
Director, Upper Gulf of California and Colorado River Delta Biosphere Reserve
msau@conanp.gob.mx

Osvel Hinojosa Huerta
Water and Wetlands Program, Pronatura Noroeste
ohinojosa@pronatura-noroeste.org

About Us

Estero Río Colorado is a WHSRN site of International Importance and part of the Alto Golfo de California y Delta del Río Colorado Biosphere Reserve, located in northwestern Mexico spanning the boundary of Baja California and Sonora. The area designated by WHSRN contains 240,000 hectares surrounding the point where the mouth of the Colorado River enters the Gulf of California.

The climate of the region is extreme. There are two rainy periods (summer and winter), but they are very sporadic (68 mm per year). Throughout the site, there are extreme temperature variations, high levels of evaporation, high salinity, constant deposit of fine sediments, and large tidal ranges (7-10 m vertical).

The three major types of habitat for shorebirds are: (1) the mudflats of the Colorado River Delta and coast located northwest of the Reserve, (2) the sandy beaches of the eastern coastline (used during spring migration), and (3) the brackish system located north of Cienega de Santa Clara.

Estero Río Colorado is one of five WHSRN sites on the Gulf of California. On the eastern shore, in the state of Sinaloa lies: Bahía de Santa María (Hemispheric), Ensenada de Pabellones (International), and Playa Ceuta (Regional). Ensenada de la Paz is a Site of Regional Importance on the western shore in the state of Baja California Sur.

Shorebirds

The site supports more than 160,000 shorebirds annually. Most (80%) are small-size shorebirds, while 15% are large and 5% are medium-size. Most small shorebirds are Western Sandpipers (Calidris mauri) using the area of the Montague and Pelican Islands. Also on the eastern shore, modest numbers of Sanderlings (Calidris alba) are observed. Among the large shorebirds, Willet (Tringa semipalmata; approx. 8,000 birds) and Marbled Godwit (Limosa fedoa, approx. 3,000 birds) are the most common. The numbers above correspond to winter populations.

Additionally, the sandy beach south of Golfo de Santa Clara, Sonora, is a very important site for the Pacific coast population of Red Knot (Calidris canutus roselaari) during spring migration and for Sanderlings. Up to 4,500 and 10,000 birds, respectively, can be observed. These Red Knots represent up to 26% of the roselaari subspecies, underscoring the site's internationally important status. In the spring, Black-bellied Plover (Pluvialis squatarola), Western Sandpiper, Marbled Godwit, Willet, Surfbird (Calidris virgata) and Dunlin (Calidris alpina) are also seen in modest numbers.

Other Designations

Estero Río Colorado is also recognized as a Priority Wetland for shorebirds in Mexico by the Mexican National Shorebird Conservation Strategy; an Important Bird Area (AICA 106) by Birdlife International; and three Ramsar sites (numbers 0814, 1822, and 1866).

In the News

A pulse of life at the mouth of the Colorado

The Accidental Wetland in the Colorado Delta from National Geographic

Returning the Colorado River to the Sea from National Geographic

Ecology & Conservation

Environment

There are three major types of environments for shorebirds at Estero Río Colorado: mudflats, sandy beaches, and a brackish marsh. The most important mudflat site is in the vicinity of Montague and Pelican islands at the mouth of the Colorado River. There is also a mudflat north of the town of Golfo de Santa Clara which is extensive due to the remarkable tidal range . South of Golfo de Santa Clara the sandy beach extends about 40 km and is fringed by dunes. These beaches are the spawning areas for pejerrey (Leuresthes sardina) in spring. The eggs of this species are prized by shorebirds, so in spring this area is important for many species. Finally, the brackish marsh known as Cienega de Santa Clara, is located on the east side of the Colorado River Delta in Sonora. It covers 18,000 hectares of dense cattail marshes, lagoons and mudflats . The marsh is currently the most important wetland in the Sonoran Desert and provides important habitat for a variety of species. The Cienega de Santa Clara was dominated by extensive scrub and wetlands before construction of the Hoover Dam in the United States. Since 1975 wetlands have almost disappeared in Mexico, but brackish water originating from irrigation in the United States have restored a piece of this marsh.

Threats

There are general threats that can cover all three environments (mudflats, sandy beaches, marshes), such as the use of agrochemicals in the surrounding agricultural areas, excessive population growth, and an increase in tourism. Specific to the Cienega de Santa Clara, the implementation of desalination plants and a decline in acreage under cultivation in Yuma could mean that the marsh will receive less water increasing its saltiness. During the spring holidays, particularly "Easter", the sandy beaches become a tourist attraction with high traffic including beach vehicles ( cars and quads) and dogs. Developments planned for these beaches, such as, golf courses and marinas could also be a future threat. The biggest threats for the mudflats involve extractive activities such as fishing and clamming.

Special Information

Coming soon...

Contact

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Reserva de la Biosfera Alto Golfo de California y Delta del Río Colorado

Martín Sau Cota
Director, Upper Gulf of California and Colorado River Delta Biosphere Reserve
msau@conanp.gob.mx

Eduardo Soto Montoya
Upper Gulf of California and Colorado River Delta Biosphere Reserve
esoto@conanp.gob.mx
eduardosotojr@gmail.com

Martha M. Gómez Sapiens
University of Arizona
sneipas@gmail.com

Martha Judith Román Rodríguez
Department of Conservation, Commission on Ecology and Sustainable Development of Sonora
martharoman@cedes.gob.mx

Osvel Hinojosa Huerta
Water and Wetlands Program, Pronatura Noroeste
ohinojosa@pronatura-noroeste.org

Gustavo D. Danemann
Executive Director, Pronatura Noroeste
gdamemann@pronatura-noroeste.org

Adriana Hernández Alvarez
Ensenada Center for Scientific Research and Higher Education (CICESE)
ahdezalvarez13@gmail.com

Eric Mellink
Ensenada Center for Scientific Research and Higher Education (CICESE)
emellink@cicese.mx

Roberto Carmona
Autonomous University of Baja California Sur
beauty@uabcs.mx

Mariela Amador Amao
Autonomous University of Baja California Sur
punk_rancid5@hotmail.com

Additional Resources

Bibliography relevant to this WHSRN Site:

Carmona, R., G. Danemann, A. Hernández Alvarez, E. Soto Montoya, J. M. Bustamante, R. Cruz, V. Ayala Perez, G. Gutiérrez, L. Mendoza & G. Marrón. 2011. Importancia del Golfo de Santa Clara, Reserva de la Biosfera Alto Golfo de California-Río Colorado, para la conservación del Playero rojizo (Calidris canutus roselaari). Informe Final para Sonoran Joint Venture. 35p.

Carmona, R., G. Danemann, A. Hernández Alvarez, E. Soto Montoya, A. Fuentes Moreno, G. Gutiérrez, L. Mendoza, G. Morán, N. Arce, F. Molina & H. Ortiz. 2012. Utilización del Golfo de Santa Clara, Sonora, Reserva de la Biosfera Alto Golfo de California y Delta del Río Colorado, durante la migración primaveral (2012) del Playero rojizo del Pacífico (Calidris canutus roselaari). Informe Final para Sonoran Joint Venture. 26p.

Carmona, R., N. Arce, V. Ayala, A. Hernández Alvarez, J. B. Buchanan, L.J. Salzer, P. Tomkovich, J.A. Johnson, R.E. Gill, Jr., B.J. McCaffery, J.E. Lyons, L.J. Niles, & D. Newstead. In press. Overview of Red Knot (Calidris canutus roselaari) migration connectivity and non-breeding distribution along the Pacific coast of the Americas.Wader Study Group Bull.

Davis, O.K. (editor). 1990. Quaternary Geology of Bahía Adair and the Grand Desierto Region. Deserts Past and Future Evolution. IGCP 252.

Gómez-Sapiens, M. M. & E. Soto-Montoya. 2006. Programa de Monitoreo de Aves Playeras en Humedales Prioritarios de la Reserva de la Biosfera Alto Golfo de California y Delta del Río Colorado. Informe final. CONANP. México. 56 p.

Gómez-Sapiens, M. M., E. Soto Montoya & O. Hinojosa Huerta. 2013. Shorebird abundance and species diversity in natural intertidal and non-tidal anthropogenic wetlands of the Colorado River Delta, Mexico. Ecological Engineering, http://dx.doi.org/10.1016/j.ecoleng.2013.03.004

Hernández-Alvarez, A. 2011. Estrategias de alimentación del playero rojizo del Pacífico (Calidris canutus roselaari; Charadrii: Scolopacidae) en el Golfo de Santa Clara, Sonora, México. Informe Final de Servicio Social (requerido para obtener el grado de licenciado en Biología). Universidad Autónoma Metropolitana- Xochimilco.

Hernández-Alvarez, A., R. Carmona & N. Arce. In press. Feeding ecology of thePacific Red Knot (Calidris canutus roselaari) at Golfo de Santa Clara, Sonora, México. Wader Study Group Bull.

Hinojosa-Huerta, O., S. Destefano, Y. Carrillo Guerrero, W. W. Shaw & C. Valdés Casillas. 2004. Waterbird communities and associated wetlands of the Colorado River Delta, México. Studies in Avian Biology 27:52–60.

Hinojosa-Huerta, H., E. Soto-Montoya, M. Gómez-Sapiens, A. Calvo-Fonseca, R. Guzmán-Olachea, J. Butrón-Méndez, J. J. Butrón-Rodríguez & M. Román-Rodríguez. 2013. The Birds of the Ciénega de Santa Clara, a wetland of international importance within the Colorado River Delta. Ecological Engineering. En prensa.

Massey, B. & E. Palacios. 1994. Avifauna of the wetlands of Baja California, Mexico: current status. Studies Avian Biology, 15: 45-57.

Mellink, E., E. Palacios & S. González. 1997. Non-breeding waterbirds of the Delta the Río Colorado, México. Journal of Field Ornithology, 68: 113-123.

Morrison, R.I.G., R. K. Ross & S. Torres. 1992. Aerial surveys of Neartic Shorebirds wintering in Mexico: some preliminary results. Canadian Wildlife Service. Progress Notes 11 p.

Patten, M. A., E. Mellink, H. Gómez de Silva & T. E. Wurster. 2001. Status and taxonomy of the Colorado Desert avifauna of Baja California. In Birds of the Baja California peninsula: status, distribution, and taxonomy, R. A. Erickson y S. N. G. Howell (eds.). Monographs in Field Ornithology 3. American Birding Association. Colorado Springs. p. 29-63.

Román Rodríguez, M. J. & M. J. Martínez Contreras. 2011. Las aves playeras: una herramienta útil en educación ambiental para la conservación de sus hábitats. XI Congreso para el Estudio y Conservación de las Aves en México. Mazatlán, Sinaloa. 4-7 de Octubre de 2011. Resumen.

Soto Montoya, E., R. Carmona, M. Gómez, V. Ayala-Pérez, N. Arce & G. D. Danemann. 2009. Over-summering and migrant Red Knots at Golfo de Santa Clara, Gulf of California, Mexico. Wader Study Group Bull. 116: 191-194.