Transcript Document
Birds and the Salton Sea An exploration of the importance of the Salton Sea and associated ecosystems to birds: a global and regional perspective Presented to: California Water Dialogue Sept. 16, 2003 Los Angeles Daniel S. Cooper, M.Sc. (University of California, Riverside) Director of Bird Conservation Audubon California Pasadena Birds and the Salton Sea Habitat diversity in the Lower Colorado River Valley (“LCR”) ecosystem Rare vs. rare Defining the Salton Sea avifauna (= birdlife) Outlook for Salton Sea avifauna, and what Audubon is doing to help Key bird habitats of the Salton Sea/LCR Valley (in no order) Shallow, open water – Salton Sea, northern Gulf of California Islands Freshwater/brackish marsh – LCR and tribs.; seeps in large canals; unlined smaller canals Mudflat/Impoundment – Mainly South End Salton Sea Mesquite Bosque – Algodones Dunes, Lower Colorado River Valley Cottonwood/Willow Woodland – Lower Colorado River Valley, Locally in Imperial Valley Agricultural fields – Mainly Imperial and Mexicali Valleys; locally elsewhere Rare vs. “rare” Species formerly common in California, now declining or lost entirely – Generally due to habitat loss – e.g. Burrowing Owl, Mountain Plover Species formerly absent or in low numbers; now present but still rare – Due to habitat alteration or climate/global change – e.g. Gull-billed Tern Species never common in California, and only occurring as vagrants – Chased by bird-watchers; of low conservation concern The Salton Sea avifauna Lower Colorado River (“LCR”) Endemics “Last Stand” breeders/winterers Winter congregants Summer dispersers Passage migrants Vanishing (vanished?) nesters Lower Colorado River “Endemics” Confined to extreme northwestern Mexico, western AZ, southern NV and southeastern CA – – – – – “Yuma” Clapper Rail “Van Rossem’s” Gull-billed Tern Abert’s Towhee “Salton Sea” Song Sparrow “Large-billed” Savannah Sparrow Clapper Rail Gull-billed Tern “Last Stand” Breeders/Winterers Mountain Plover – 30-40% Global population in Imperial Valley (formerly widespread) Burrowing Owl – 70% of California pop. in Imperial Valley – Associated with agricultural fields – 60% of CA population lost in 1980s Western Snowy Plover – Largest wintering concentration in interior of U.S. – Major interior-U.S. breeding site Winter congregants Begin arriving late July/August – November Occur in two main roles: – Agricultural fields Largest agricultural/grassland area in southern California – The Salton Sea itself Largest and shallowest body of water in California Winter congregants… (agricultural) From left: Sandhill Crane, Long-billed Curlew, White-faced Ibis One of just 3 crane wintering areas left in SoCal (formerly common) 20K+ curlews wintering each year Bob Miller 40K ibis wintering each year Winter congregants… (the Salton Sea itself) Up to 75% of N. Am. pop. passes through in early spring (from Gulf of CA to Great Basin) David Blevins 1.5 million birds in winter Bob Miller “Lost” shallow water lakes: Tulare Lake, Owens Lake, San Jacinto Lake Buena Vista Lake; plus most coastal wetlands south of SF Bay… Winter congregants… (the Salton Sea itself) Black-necked Stilt Am. White Pelican American Avocet 100+ miles of shoreline 10s of thousands of shorebirds on shoreline and adj. impoundments David Blevins 30% of Global AWP pop. Bob Miller “Lost” shallow water lakes: Tulare Lake, Owens Lake, San Jacinto Lake Buena Vista Lake; plus most coastal wetlands south of SF Bay… And lots in between… Freshwater impoundment at the edge of the Sea (southeast corner) c. 30,000 Snow and Ross’ Geese David Blevins 100,000+ other waterfowl Bob Miller Richard Ditch Summer Dispersers: north out of the Gulf (Looking south) Large-billed Savannah Sparrow Yellow-footed Gull, Brown Pelican Passage migrant songbirds Spring: Along eastern Gulf of California and directly through Salton Trough Fall: In hills west and east of Salton Trough Extensive use of native riparian and mesquite habitat Vanishing (from CA) species Harris’ Hawk Elf Owl Fulvous Whistling-Duck Vanishing (from CA) species • Elf Owl • Formerly common along LCR – now 1-5 pr. (if still breeds) • Most of habitat cleared for agriculture • Harris’ Hawk • Extirpated from Imperial Valley c. 1955, from LCR (CA) c. 1965 • Fulvous Whistling-Duck • Formerly (pre-1950) bred throughout southern Calif. wetlands • Fairly common at South End Salton Sea Impoundments until 1990s Outlook for the Sea “Do nothing” (Increased salinity/pollutants = fewer fish) Declines in pelicans Unhealthy birds? – Lower Colorado River continues to dry/degrade “Save” the Sea w/o retaining some agriculture – No more Burrowing Owl, Sandhill Crane, curlews, etc. Audubon is pushing for maximum restoration of entire LCR system, including the Salton Sea – – – – Improvement to threatened ecosystems Reflective of historic conditions No “net loss” of birds No increase of exotic vegetation Thanks! Audubon California is the state office of the National Audubon Society. Formally established in 1996, it has its own Board of Directors and staff; manages >10,000 acres of centers and lands throughout the state; and raises 100% of its operating funds.