The
Important Bird Areas Program (IBA) is a global effort to
identify and conserve areas that are vital to birds and other
wildlife. By working with Audubon
chapters, landowners, public agencies, community groups, and other
non-profits, Audubon endeavors to interest and activate a broad
network of supporters to ensure that all Important Bird Areas are
properly managed and conserved.
The
10,561-acre South Fork Kern River
Valley is one of the first ten 'Globally
Important Bird Areas" designated in the United States.
This IBA is home to many endangered
species, unique habitats, and areas of cultural significance. The
Kern River is the southernmost major river in the Sierra Nevada, and
its watershed extends from the highest point in the state south and
west into the southern San Joaquin Valley. Its two main arms, the
North Fork, which drains the High Sierra, and the South Fork, which
originates on the Kern Plateau (the southern terminus of the
Sierra), meet in the 560,000-acre-foot reservoir “Lake Isabella.”
One of the most biologically diverse areas in North America, the
region is the intersection of significant geological and floristic
provinces. The South Fork Kern River Valley is home to one of the
largest and best-preserved examples of lowland riparian woodland
(Fremont cottonwood-willow) in the state. Other major habitat
communities include Joshua tree woodland, wet meadow, freshwater
marsh, Mojave Desert scrub, desert chaparral, and annual grassland.
Several privately held cattle ranches remain unprotected totaling
7,223 acres, with a total of 12,043 acres protected as conservation
lands (through fee title or conservation easements) from the eastern
edge of Isabella Reservoir east past the community of Onyx. These
include South Fork Wildlife Area (1,200 acres owned by the U.S.
Forest Service) at the eastern edge of Lake Isabella; the Kern River
Preserve (3,000
acres owned by Audubon) just to the east; Canebrake Ecological
Reserve (6,938 acres owned by the DFG) which includes all of Fish &
Game’s holdings of riparian and upland habitats in the South Fork
Valley; and Hafenfeld Ranch conservation easement (233 acres).
The South Fork Kern River riparian forest supports the largest
breeding population of Western Yellow-billed Cuckoo (California
Listed as Threatened) left in the western U.S. The Southwestern
Willow Flycatcher (Federally Listed as Endangered) is the focus of
much of the restoration and habitat protection in the Kern River
Valley. An understudied subspecies, the Kern Red-winged Blackbird,
this bird’s global distribution is limited to the mid Kern River
watershed. The wetlands in the South Fork Kern also support colonies
of Tricolored Blackbirds (Audubon Watch List species and CDF Species
of Special Concern). This forest also supports the most northwest
breeding colonies of several southwestern desert species: Summer
Tanager, Vermilion Flycatcher and Brown-crested Flycatcher. The
riparian bird community is exceptionally rich on the Kern River
Preserve, with 110 species documented as nesters, and 140 species
breeding in the South Fork Valley as a whole. Mid-summer bird
censuses have documented over 300 Yellow Warblers and over 1,000
Song Sparrows. Seven species of blackbirds feed in agricultural
fields and feedlots in the valley. Alkali meadows and wet grasslands
support an interesting interior-coastal blend of species, including
White-tailed Kite, Northern Harrier, Wilson’s Snipe and Grasshopper
Sparrow. Spring migration is spectacular, with thousands of
songbirds moving through the riparian forest in late April to
mid-May. The highlight of fall migration is the annual flight of up
to 30,000 southbound Turkey Vultures. The afternoon flights normally
stop to roost overnight in the riparian forest during September and
October.
Information on
Audubon IBA's can be found at:
http://www.audubon.org/bird/iba/index.html
California IBA information is available on the Audubon
California
website,
http://ca.audubon.org/IBA.htm.
The Kern River Preserve/South Fork Kern
River is one of four "Flagship Projects" of the California Riparian
Habitat Joint Venture.
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