Birds of the Coastal Wetlands of Southern Sonora: Status and Conservation

Osvel Hinojosa Huerta

The Importance of Southern Sonora for Birds

• Over 260 species

• Critical wintering and stopover site in the Pacific Flyway

• Waterfowl (120,000; 25 species)

• Shorebirds (90,000; 28 species)

The Importance of Southern Sonora for Birds

• Stopover site for Neotropical migratory landbirds

The Importance of Southern Sonora for Birds

• Breeding waterbirds• Marshbirds• Colonial waterbirds

• Protected Species• 19 species• Least Tern• Clapper Rail• Piping Plover• Brant• Least Grebe

The Importance of Southern Sonora for Birds

• 7 AICAs (Important Bird Areas)

• Important site for North American Wetlands Conservation Council

• Priority Site for Conservation of Biodiversity in the Gulf of California

Threats to Birds in Southern Sonora

• Habitat loss and degradation

• Mangrove areas• Freshwater and brackish marshes• Riparian areas

• Disturbance of breeding grounds

• Pollution

Threats to Birds in Southern Sonora

• Reduced avian productivity and survivorship

• Population declines

• Local extirpations

• Loss of biodiversity

Birds as Indicators of Environmental Health

0

0.5

1

1.5

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3.5

1999 2000 2001 2002 2003

Rails per station

Lineal (Rails perstation)

Marshbirds of Southern Sonora

• Breed in areas with emergent vegetation or mangroves

• Strongest dependence upon wetland ecosystems

• Sharp population declines in North America: habitat loss

• More drastic in the Sonoran Desert Ecoregion

Marshbirds of Southern Sonora

• 5 species

ArdeidaeAmerican Bittern - Botaurus lentiginosus Least Bittern - Ixobrychus exilis

RallidaeClapper Rail - Rallus longirostrisVirginia Rail - Rallus limicolaSora - Porzana carolina

Marshbirds of Southern Sonora

Marshbirds of Southern Sonora

• Determine the status of marshbirds in SS and set a baseline for a long-term monitoring program

• Part of a regional effort to determine the relative abundance and distribution of marshbirds in Northwestern Mexico

• Linked to a continental effort to estimate population trends of marshbirds in NA (USGS; USFWS)

Protocol

• Standardized Protocol for Monitoring Marshbirds in North America (Conway 2002)

• Based on call-response surveys: 30 s of vocalizations of each species, followed by 30 s of silence

• Counts during breeding season, when vocalization rate increases (May-June)

Protocol

• Variable distance point counts

• Survey stations 200 m apart

• Grouped in transects (5 stations)

• Counting the number of individuals of each species responding to the tapes, along with distance estimation

• Habitat measurements at each station: cover classes, veg height, salinity, and water depth

• Support with GIS and satellite images for change analysis and density estimates

Protocol

Surveyed WetlandsSonoraDelta del Río ColoradoEstero Santa Rosa, Estero del Soldado, Sur de Sonora

Baja CaliforniaPunta Banda, Río San Telmo, Bahía San Quintín, El Rosario, Laguna Guerrero Negro

Baja California SurLaguna Ojo de Liebre, Laguna San Ignacio, Bahía Magdalena, Ensenada La Paz, San José del Cabo

SinaloaEnsenada Pabellones y Bahía Santa María

Surveyed Wetlands in Southern Sonora

• Estero Santa Cruz

• Punta Santa Rosa

• El Soldado

• Miramar

• Tobari System

• Yavaros

• Huatabampo

• Agiabampo

Wetland Survey Points

Punta Santa Rosa 8

Estero Santa Cruz 13

Estero del Soldado 10

Estero Miramar 10

Dren Tobari 10

Bahia Tobari 25

Dren Huatabampo 6

Yavaros 15

Agiabampo 8

Total 105

Total Survey Effort

Preliminary Results

• 124 individuals from 4 species

• Clapper Rails are common in mangrove areas

• Distribution is patchy; some mangrove areas without CLRAs

• Other marshbirds are very scarce

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CLRA LEBI

VIRA AMBI

Marshbird Abundance

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Kino Guaymas Dren Tobari Tobari DrenHuatabampo

Yavaros Agiabampo

CLRA/station

Mbirds/station

Marshbird Density

Preliminary Results

Region birds/station

Southern Sonora 1.1810

Baja California Sur (MB, LP, GN) 0.9971

Santa Maria, Sinaloa 3.6330

Colorado River Delta 4.0812

Baja California (Pacific) 1.9542

Next Steps…

• Data analysis and reporting

• Develop and implement monitoring plan

• Regional Conservation Plan for Marshbirds

• Include other guilds and species to assess the status of the wetlands of Southern Sonora

Next Steps…

• Outreach and Environmental Education

• Support decision making and management

• Conservation!