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
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
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
– 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
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’
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
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
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.