San Luis National Wildlife Refuge Complex
Encyclopedia
The San Luis National Wildlife Refuge Complex is managed by the U.S Fish & Wildlife Service
and is composed of the San Luis National Wildlife Refuge, Merced National Wildlife Refuge, San Joaquin River National Wildlife Refuge and the Grasslands Wildlife Management Area which consists of nearly 45000 acres (182.1 km²) of wetlands, grasslands and riparian habitats
, as well as over 90000 acres (364.2 km²) of conservation easements on private lands for the protection and benefit of wildlife. The refuge units are located in the northern San Joaquin Valley
of California
in Merced
and Stanislaus
Counties. The Complex is Headquarter out of Los Banos, California
and uses the Sierra National Forest
Emergency Communication Center
located in Fresno, California
for Emergency dispatch.
The Complex is located within the Pacific Flyway
, a major route for migrating birds, including waterfowl. The extensive wetlands of the Complex and surrounding lands provide habitat for up to a million waterfowl that arrive here each winter. Of the 30 species of waterfowl using the Complex, the most common include Ross's Geese
, Aleutian cackling geese
, snow geese
, green-winged teal
, mallard
, northern pintail
, gadwall
, American wigeon
, northern shoveler
, and white-fronted geese.
The Complex is an integral part of a mosaic of federal, state, and private lands in Merced County that together constitute the largest contiguous freshwater wetlands remaining in California. This area has been recognized as a Ramsar Wetland of International Importance, an Audubon Important Bird Area, and as a Western Hemisphere Shorebird Reserve Network site.
is showcased by one of three auto tour routes. The refuge is host to significant assemblages of birds, mammals, reptiles, amphibians, insects and plants; some of which, such as the tiger salamander
and San Joaquin kit fox
, are endangered species
.
In 1966, the first parcel of the refuge was purchased with Federal Duck Stamp funds
to provide a sanctuary for migratory waterfowl. Over the years the refuge has steadily grown in size and today it comprises six contiguous units: San Luis, East Bear Creek, West Bear Creek, Freitas, Blue Goose, and Kesterson. The San Joaquin River
bisects the eastern portion of the Refuge.
The refuge is a major wintering ground and migratory stopover point for large concentrations of waterfowl, shorebirds and other waterbirds. Large flocks of northern shoveler
, mallard
, gadwall
, wigeon
, green-winged teal
, cinnamon teal
, northern pintail
, ring-billed duck, canvasback
, ruddy duck
, Snow Goose
Ross’s Geese
and white-fronted geese swarm over the mosaic of seasonal, and permanent wetlands that comprise a quarter of the refuge. Waterfowl generally remain until mid April before beginning their journey north to breeding areas. Some mallard, gadwall, and cinnamon teal stay through the spring and summer and breed on the refuge.
Shorebirds including sandpipers and plovers can be found in the tens of thousands from autumn through spring. Large flocks of dunlin
, long-billed dowitchers
, least sandpipers
and western sandpipers
can be found feeding in shallow seasonal wetlands, whereas flocks of long-billed curlews
are found using both wetlands and grasslands. Over 25 species of shorebirds have been documented at the San Luis NWR.
The San Luis NWR has played a key role in the recovery of the tule elk
, a non-migratory elk subspecies found only in California. Prior to the mid-19th century, an estimated 500,000 tule elk lived in California. Due to over-hunting and loss of natural habitat, they were nearly driven to extinction by the turn of the 20th century – by some accounts, the population was down to 10-20 individuals. In 1974 a herd of 18 animals was established in a large enclosure at the San Luis NWR and has since thrived. Elk from this herd are periodically relocated to establish new or join other tule elk herds throughout California. A true wildlife recovery success story, the statewide tule elk population has recovered to over 4,000 animals.
Less well known are the extensive upland habitats found on the refuge. Many of these habitats are characterized by saline or alkaline conditions which are accentuated by the low rainfall and arid conditions that characterize the San Joaquin Valley. These habitats support a rich botanical community of native bunchgrasses, native and exotic annual grasses, forbs, and native shrubs. Trees, such as the valley oak
, cottonwood, and willow
are found along riparian corridors. In these areas, visitors might encounter coyotes, desert cottontail rabbits
, ground squirrels, western meadowlarks
, yellow-billed magpies
, loggerhead shrikes
, as well as northern harriers
and white-tailed kites
coursing over the vegetation and other raptors. Stately great blue herons, great egrets
and White-faced Ibis
are frequently sighted throughout the refuge.
The Refuge has three auto tours routes with associated nature trails and observation decks for the public to view and photograph wildlife and nature. The Refuge also allows fishing at designated sites and has a large waterfowl hunting program.
The Refuge plays host to the largest wintering populations of lesser Sandhill cranes
and Ross's geese
within the Pacific Flyway. Each autumn over 20,000 cranes and 60,000 Arctic Nesting Geese terminate their annual migrations from Alaska
and Canada
to make the Refuge home for six months. Here they mingle with thousands of other visiting waterfowl, waterbirds and shorebirds making the Refuge a true winter phenomenon.
The Refuge also provides important breeding habitat for Swainson’s hawks
, tri-colored blackbirds, marsh wren
s, mallards, gadwall, cinnamon teal, and burrowing owl
s. Tri-colored blackbirds, a colonial-nesting songbird, breed in colonies of over 25,000 pairs. Coyotes, ground squirrels, desert cottontail rabbits, beaver
s, and long-tailed weasel
s can also be seen year-round.
Vernal pools are another type of wetland found on the Merced NWR. These special pools form when natural shallow depressions underlaid with clay soils fill with winter rainwater. The pools come to life as they fill with water: fairy
and tadpole shrimp emerge from cysts embedded in the soils the previous year. The endangered tiger salamander, along with other amphibians lay eggs and rear tadpoles. The vast number of aquatic invertebrates found in these pools provides a food source for wintering and migrating birds as they prepare for the long flight north to their breeding grounds.
As spring arrives and the water in the vernal pools evaporates, wildflowers – such as goldfields
, purple owl's clover, and butter-and-egg
– germinate in colorful patterns of thick rings or halos around the pool basins. Once the vernal pools have dried out, Downingia
and Colusa
grass, a rare California species, appear in the parched basins. This annual coloring led John Muir
to describe the valley floor as the “floweriest part of the world” he had seen.
In addition to managing natural habitats, the Merced NWR contains approximately 300 acres (1.2 km²) of cultivated corn and winter wheat crops and over 500 acres (2 km²) of irrigated pasture for wildlife. Not only do these managed agricultural areas provide important sources of nutrition (carbohydrates) to the tens of thousands of arctic-nesting geese and Sandhill cranes that make Merced County their winter home, they also help ensure that the birds will have adequate nutrient stores to make the long migration to their northern breeding grounds. Local farmers, under agreements with the Refuge, oversee the ground preparation, seeding, and irrigation of these croplands. The Refuge incorporates a livestock grazing program that works in partnership with local ranchers and farmers. Grazing cattle and sheep is a management tool used by the Refuge to help control invasive weeds, provide and maintain short stature grasslands for goose grazing, and encourage native grasslands to thrive
, Tuolumne
and Stanislaus) join providing a key travel corridor for wildlife. The refuge was established in 1987 under the Endangered Species Act
and the Migratory Bird Treaty Act of 1918
.
The Refuge has played a major role in the recovery of Aleutian cackling geese
by serving as a key wintering area and continues to be of major importance to this species. By 1975, the total population was under 1,000 geese; however, removing nest predators (non-native introduced foxes) from the breeding grounds in Alaska’s Aleutian Islands and improving wintering habitat resulted in its delisting as an endangered species and a population well over 100,000 and growing. Restoring wetlands and providing grasslands and croplands at this refuge has provided ideal wintering habitat for the geese.
It is estimated that 95 percent of the San Joaquin Valley’s riparian woodlands were lost during the last century due to changing land uses; however, this refuge is in the process of restoring this critical habitat. Within the borders of the San Joaquin NWR is one of California’s largest riparian forest restoration projects: 400,000 native trees such as willows, cottonwoods and oaks have been planted across 1700 acres (7 km²) of river floodplain creating the largest block of contiguous riparian woodland in the San Joaquin Valley. This important riparian woodland habitat is host to many rare animals. Swainson’s hawks nest in the canopy of tall cottonwood trees. Herons and cormorants form communal nesting colonies within the tops of the large oaks. Endangered riparian brush rabbits have been re-introduced to this restored habitat from captive-reared populations. These woodlands also support a diversity of breeding songbirds including grosbeak
s, oriole
s, flycatcher
s, warbler
s, as well as least Bell's Vireo
s – a threatened species which last nested in the San Joaquin Valley over 50 years ago.
A wildlife viewing platform along Beckwith Road is a favorite location for viewing the Aleutian cackling geese along with other waterbirds from October through March.
The GWMA is located in western Merced County, California, within the San Joaquin River basin and supports the largest remaining block of contiguous wetlands in the Central Valley. It is divided into an eastern and western division separated by the San Joaquin River. In the heart of the western division is the Grassland Resource Conservation District (GRCD), an area of 70000 acres (283.3 km²) of private wetlands and associated grasslands, and over 30600 acres (124 km²) of federal National Wildlife Refuges and state Wildlife Management Areas.
These private wetlands constitute 30% of the remaining wetlands in California's Central Valley and are extremely important to Pacific Flyway waterfowl populations. Over 60 million duck use-day and 3 million goose use-days occur annually in the GWMA. The wetlands support diverse habitats including seasonally flooded marshlands, semi-permanent marsh, riparian habitat, wet meadows, vernal pools, native uplands, pastures, and native grasslands. This habitat diversity supports raptors, shorebirds, wading birds, and other wildlife species. Several federal and state listed, endangered, and threatened plants and animals are present in the area and benefit by the habitat protection provided by the easement program.
United States Fish and Wildlife Service
The United States Fish and Wildlife Service is a federal government agency within the United States Department of the Interior dedicated to the management of fish, wildlife, and natural habitats...
and is composed of the San Luis National Wildlife Refuge, Merced National Wildlife Refuge, San Joaquin River National Wildlife Refuge and the Grasslands Wildlife Management Area which consists of nearly 45000 acres (182.1 km²) of wetlands, grasslands and riparian habitats
Riparian zone
A riparian zone or riparian area is the interface between land and a river or stream. Riparian is also the proper nomenclature for one of the fifteen terrestrial biomes of the earth. Plant habitats and communities along the river margins and banks are called riparian vegetation, characterized by...
, as well as over 90000 acres (364.2 km²) of conservation easements on private lands for the protection and benefit of wildlife. The refuge units are located in the northern San Joaquin Valley
San Joaquin Valley
The San Joaquin Valley is the area of the Central Valley of California that lies south of the Sacramento – San Joaquin River Delta in Stockton...
of California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
in Merced
Merced County, California
Merced County , is a county located in the Central Valley of the U.S. state of California, north of Fresno and southeast of San Jose. As of the 2010 census, the population was 255,793, up from 210,554 at the 2000 census. The county seat is Merced...
and Stanislaus
Stanislaus County, California
Stanislaus County is a county located in the Central Valley of the U.S. state of California. As the price of housing has increased in the San Francisco Bay Area, many people who work in the southern reaches of the Bay Area have opted for the longer commute and moved to Stanislaus County for the...
Counties. The Complex is Headquarter out of Los Banos, California
Los Banos, California
Los Banos is a city in Merced County, California, near the junction of State Route 152 and Interstate 5. Los Banos is located southwest of Merced, at an elevation of 118 feet . The population was 35,972 at the 2010 census, up from 25,869 at the 2000 census...
and uses the Sierra National Forest
Sierra National Forest
Sierra National Forest is a U.S. National Forest located on the western slope of central Sierra Nevada in the state of California. The forest is known for its mountain scenery and natural resources. Forest headquarters are located in Clovis, California...
Emergency Communication Center
Fresno Air Attack Base
The Fresno Air Attack Base was established in 1955 By the US Forest Service, Sierra National Forest and is located at the Fresno Yosemite International Airport. The US Forest Service leases office space to the California Department of Forestry and Fire Protection's Fresno/Kings Unit...
located in Fresno, California
Fresno, California
Fresno is a city in central California, United States, the county seat of Fresno County. As of the 2010 census, the city's population was 510,365, making it the fifth largest city in California, the largest inland city in California, and the 34th largest in the nation...
for Emergency dispatch.
The Complex is located within the Pacific Flyway
Pacific Flyway
The Pacific Flyway is a major north-south route of travel for migratory birds in America, extending from Alaska to Patagonia. Every year, migratory birds travel some or all of this distance both in spring and in fall, following food sources, heading to breeding grounds, or travelling to...
, a major route for migrating birds, including waterfowl. The extensive wetlands of the Complex and surrounding lands provide habitat for up to a million waterfowl that arrive here each winter. Of the 30 species of waterfowl using the Complex, the most common include Ross's Geese
Ross's Goose
The Ross's Goose is a North American species of goose.The American Ornithologists' Union places this species and the other two "white" geese in the genus Chen rather than the more traditional "grey" goose genus Anser.This goose breeds in northern Canada, mainly in the Queen Maud Gulf Migratory...
, Aleutian cackling geese
Aleutian Cackling Goose
The Aleutian Cackling Goose , formerly known as the Aleutian Canada Goose , is small subspecies of Cackling Goose averaging 1700 to 2100 grams....
, snow geese
Snow Goose
The Snow Goose , also known as the Blue Goose, is a North American species of goose. Its name derives from the typically white plumage. The genus of this bird is disputed...
, green-winged teal
Green-winged Teal
The Green-winged Teal is a common and widespread duck that breeds in the northern areas of North America except on the Aleutian Islands. It was considered conspecific with the Common Teal The Green-winged Teal (Anas carolinensis) is a common and widespread duck that breeds in the northern areas of...
, mallard
Mallard
The Mallard , or Wild Duck , is a dabbling duck which breeds throughout the temperate and subtropical Americas, Europe, Asia, and North Africa, and has been introduced to New Zealand and Australia....
, northern pintail
Northern Pintail
The Pintail or Northern Pintail is a widely occurring duck which breeds in the northern areas of Europe, Asia and North America. It is strongly migratory and winters south of its breeding range to the equator...
, gadwall
Gadwall
The Gadwall is a common and widespread duck of the family Anatidae.- Description :The Gadwall is 46–56 cm long with a 78–90 cm wingspan. The male is slightly larger than the female, weighing on average 990 g against her 850 g...
, American wigeon
American Wigeon
The American Wigeon, also American Widgeon or Baldpate, is a species of wigeon in the dabbling duck genus Anas. If this is split up, all wigeons will go into their old genus Mareca again...
, northern shoveler
Northern Shoveler
The Northern Shoveler , Northern Shoveller in British English, sometimes known simply as the Shoveler, is a common and widespread duck. It breeds in northern areas of Europe and Asia and across most of North America, and is a rare vagrant to Australia...
, and white-fronted geese.
The Complex is an integral part of a mosaic of federal, state, and private lands in Merced County that together constitute the largest contiguous freshwater wetlands remaining in California. This area has been recognized as a Ramsar Wetland of International Importance, an Audubon Important Bird Area, and as a Western Hemisphere Shorebird Reserve Network site.
San Luis National Wildlife Refuge
The San Luis National Wildlife Refuge encompasses over 26600 acres (108 km²) of wetlands, riparian forests, native grasslands and vernal pools. A thriving population of tule elkTule Elk
The tule elk is a subspecies of elk found only in California, ranging from the grasslands and marshlands of the Central Valley to the grassy hills on the coast. The subspecies name derives from the tule that it feeds off of, which grows in the marshlands...
is showcased by one of three auto tour routes. The refuge is host to significant assemblages of birds, mammals, reptiles, amphibians, insects and plants; some of which, such as the tiger salamander
Tiger Salamander
The Tiger Salamander is a species of Mole Salamander. The proper common name is the Eastern Tiger Salamander, to differentiate from other closely related species.-Description:...
and San Joaquin kit fox
Kit Fox
The kit fox is a fox species of North America. Its range is primarily in the southwestern United States and northern and central Mexico. Some mammalogists classify it as conspecific with the swift fox, V. velox, but molecular systematics imply that the two species are distinct.-Range:The...
, are endangered species
Endangered species
An endangered species is a population of organisms which is at risk of becoming extinct because it is either few in numbers, or threatened by changing environmental or predation parameters...
.
In 1966, the first parcel of the refuge was purchased with Federal Duck Stamp funds
Federal Duck Stamp
The federal duck stamp was created through a wetlands conservation program. President Herbert Hoover signed the Migratory Bird Conservation Act in 1929 to authorize the acquisition and preservation of wetlands as waterfowl habitat....
to provide a sanctuary for migratory waterfowl. Over the years the refuge has steadily grown in size and today it comprises six contiguous units: San Luis, East Bear Creek, West Bear Creek, Freitas, Blue Goose, and Kesterson. The San Joaquin River
San Joaquin River
The San Joaquin River is the largest river of Central California in the United States. At over long, the river starts in the high Sierra Nevada, and flows through a rich agricultural region known as the San Joaquin Valley before reaching Suisun Bay, San Francisco Bay, and the Pacific Ocean...
bisects the eastern portion of the Refuge.
The refuge is a major wintering ground and migratory stopover point for large concentrations of waterfowl, shorebirds and other waterbirds. Large flocks of northern shoveler
Northern Shoveler
The Northern Shoveler , Northern Shoveller in British English, sometimes known simply as the Shoveler, is a common and widespread duck. It breeds in northern areas of Europe and Asia and across most of North America, and is a rare vagrant to Australia...
, mallard
Mallard
The Mallard , or Wild Duck , is a dabbling duck which breeds throughout the temperate and subtropical Americas, Europe, Asia, and North Africa, and has been introduced to New Zealand and Australia....
, gadwall
Gadwall
The Gadwall is a common and widespread duck of the family Anatidae.- Description :The Gadwall is 46–56 cm long with a 78–90 cm wingspan. The male is slightly larger than the female, weighing on average 990 g against her 850 g...
, wigeon
Wigeon
The Eurasian Wigeon, also known as Widgeon or Eurasian Widgeon is one of three species of wigeon in the dabbling duck genus Anas. It is common and widespread within its range...
, green-winged teal
Green-winged Teal
The Green-winged Teal is a common and widespread duck that breeds in the northern areas of North America except on the Aleutian Islands. It was considered conspecific with the Common Teal The Green-winged Teal (Anas carolinensis) is a common and widespread duck that breeds in the northern areas of...
, cinnamon teal
Cinnamon Teal
The Cinnamon Teal is a small, reddish dabbling duck found in marshes and ponds of western North and South America.thumb|left|Female Anas cyanoptera septentrionalium...
, northern pintail
Northern Pintail
The Pintail or Northern Pintail is a widely occurring duck which breeds in the northern areas of Europe, Asia and North America. It is strongly migratory and winters south of its breeding range to the equator...
, ring-billed duck, canvasback
Canvasback
The Canvasback is the largest of the North American diving ducks, that ranges from between long and weighs approximately , with a wingspan of . The canvasback has a distinctive wedge-shaped head and long graceful neck. The adult male has a black bill, a chestnut red head and neck, a black...
, ruddy duck
Ruddy Duck
The Ruddy Duck is a small stiff-tailed duck.Their breeding habitat is marshy lakes and ponds throughout much of North America, and in South America in the Andes. They nest in dense marsh vegetation near water. The female builds her nest out of grass, locating it in tall vegetation to hide it from...
, Snow Goose
Snow Goose
The Snow Goose , also known as the Blue Goose, is a North American species of goose. Its name derives from the typically white plumage. The genus of this bird is disputed...
Ross’s Geese
Ross's Goose
The Ross's Goose is a North American species of goose.The American Ornithologists' Union places this species and the other two "white" geese in the genus Chen rather than the more traditional "grey" goose genus Anser.This goose breeds in northern Canada, mainly in the Queen Maud Gulf Migratory...
and white-fronted geese swarm over the mosaic of seasonal, and permanent wetlands that comprise a quarter of the refuge. Waterfowl generally remain until mid April before beginning their journey north to breeding areas. Some mallard, gadwall, and cinnamon teal stay through the spring and summer and breed on the refuge.
Shorebirds including sandpipers and plovers can be found in the tens of thousands from autumn through spring. Large flocks of dunlin
Dunlin
The Dunlin, Calidris alpina, is a small wader, sometimes separated with the other "stints" in Erolia. It is a circumpolar breeder in Arctic or subarctic regions. Birds that breed in northern Europe and Asia are long-distance migrants, wintering south to Africa, southeast Asia and the Middle East...
, long-billed dowitchers
Long-billed Dowitcher
The Long-billed Dowitcher, Limnodromus scolopaceus, is a medium-sized shorebird.Adults have yellowish legs and a long straight dark bill. The body is dark brown on top and reddish underneath with spotted throat and breast, bars on flanks. The tail has a black and white barred pattern...
, least sandpipers
Least Sandpiper
The Least Sandpiper is the smallest shorebird.This species has greenish legs and a short thin dark bill. Breeding adults are brown with dark brown streaks on top and white underneath. They have a light line above the eye and a dark crown. In winter, Least Sandpipers are grey above...
and western sandpipers
Western Sandpiper
The Western Sandpiper, Calidris or Erolia mauri, is a small shorebird.Adults have dark legs and a short thin dark bill, thinner at the tip. The body is brown on top and white underneath. They are reddish-brown on the crown. This bird can be difficult to distinguish from other similar tiny...
can be found feeding in shallow seasonal wetlands, whereas flocks of long-billed curlews
Long-billed Curlew
The Long-billed Curlew, Numenius americanus, is a large North American shorebird of the family Scolopacidae. This species was also called "sicklebird" and the "candlestick bird". The species is native to central and western North America...
are found using both wetlands and grasslands. Over 25 species of shorebirds have been documented at the San Luis NWR.
The San Luis NWR has played a key role in the recovery of the tule elk
Tule Elk
The tule elk is a subspecies of elk found only in California, ranging from the grasslands and marshlands of the Central Valley to the grassy hills on the coast. The subspecies name derives from the tule that it feeds off of, which grows in the marshlands...
, a non-migratory elk subspecies found only in California. Prior to the mid-19th century, an estimated 500,000 tule elk lived in California. Due to over-hunting and loss of natural habitat, they were nearly driven to extinction by the turn of the 20th century – by some accounts, the population was down to 10-20 individuals. In 1974 a herd of 18 animals was established in a large enclosure at the San Luis NWR and has since thrived. Elk from this herd are periodically relocated to establish new or join other tule elk herds throughout California. A true wildlife recovery success story, the statewide tule elk population has recovered to over 4,000 animals.
Less well known are the extensive upland habitats found on the refuge. Many of these habitats are characterized by saline or alkaline conditions which are accentuated by the low rainfall and arid conditions that characterize the San Joaquin Valley. These habitats support a rich botanical community of native bunchgrasses, native and exotic annual grasses, forbs, and native shrubs. Trees, such as the valley oak
Valley Oak
Quercus lobata, commonly called the Valley oak, grows into the largest of North American oaks. It is endemic to California, growing in the interior valleys and foothills. Mature specimens may attain an age of up to 600 years. This deciduous oak requires year-round access to groundwater.Its thick,...
, cottonwood, and willow
Willow
Willows, sallows, and osiers form the genus Salix, around 400 species of deciduous trees and shrubs, found primarily on moist soils in cold and temperate regions of the Northern Hemisphere...
are found along riparian corridors. In these areas, visitors might encounter coyotes, desert cottontail rabbits
Desert Cottontail
The Desert Cottontail , also known as Audubon's Cottontail, is a New World cottontail rabbit, a member of the family Leporidae....
, ground squirrels, western meadowlarks
Western Meadowlark
Not to be confused with Eastern MeadowlarkThe Western Meadowlark is a medium-sized icterid bird, about 8.5 in long. It nests on the ground in open country in western and central North America. It feeds mostly on insects, but also seeds and berries...
, yellow-billed magpies
Yellow-billed Magpie
The Yellow-billed Magpie, Pica nuttalli, is a large bird in the crow family found only in California. It inhabits the Central Valley and the adjacent chaparral foothills and mountains...
, loggerhead shrikes
Loggerhead Shrike
The Loggerhead Shrike is a passerine bird. It is the only member of the shrike family endemic to North America; the related Northern Shrike occurs north of its range but also in the Palearctic....
, as well as northern harriers
Hen Harrier
The Hen Harrier or Northern Harrier is a bird of prey. It breeds throughout the northern parts of the northern hemisphere in Canada and the northernmost USA, and in northern Eurasia. This species is polytypic, with two subspecies. Marsh Hawk is a historical name for the American form.It migrates...
and white-tailed kites
White-tailed Kite
The White-tailed Kite is an elanid kite of genus Elanus found in western North America and parts of South America.Their coloration is gull-like, but their shape and flight falcon-like, with a rounded tail...
coursing over the vegetation and other raptors. Stately great blue herons, great egrets
Great Egret
The Great Egret , also known as the Great White Egret or Common Egret, White Heron, or Great White Heron, is a large, widely-distributed egret. Distributed across most of the tropical and warmer temperate regions of the world, in southern Europe it is rather localized...
and White-faced Ibis
White-faced Ibis
The White-faced Ibis is a wading bird in the ibis family Threskiornithidae.This species breeds colonially in marshes, usually nesting in bushes or low trees. Its breeding range extends from the western USA south through Mexico, as well as from southeastern Brazil and southeastern Bolivia south to...
are frequently sighted throughout the refuge.
The Refuge has three auto tours routes with associated nature trails and observation decks for the public to view and photograph wildlife and nature. The Refuge also allows fishing at designated sites and has a large waterfowl hunting program.
Merced National Wildlife Refuge
The Merced National Wildlife Refuge which is divided into four units Merced Unit, Arena Plains Unit, Snobird Unit and Lonetree Unit. this encompasses 10262 acres (42 km²) of wetlands, native grasslands, vernal pools, and riparian areas. It was established in 1951 under the Lea Act to attract wintering waterfowl from adjacent farmland where their foraging was causing crop damage. In the last few decades, changes in agricultural practices and Refuge management have reduced these wildlife/crop issues.The Refuge plays host to the largest wintering populations of lesser Sandhill cranes
Sandhill Crane
The Sandhill Crane is a large crane of North America and extreme northeastern Siberia. The common name of this bird references habitat like that at the Platte River, on the edge of Nebraska's Sandhills in the American Midwest...
and Ross's geese
Ross's Goose
The Ross's Goose is a North American species of goose.The American Ornithologists' Union places this species and the other two "white" geese in the genus Chen rather than the more traditional "grey" goose genus Anser.This goose breeds in northern Canada, mainly in the Queen Maud Gulf Migratory...
within the Pacific Flyway. Each autumn over 20,000 cranes and 60,000 Arctic Nesting Geese terminate their annual migrations from Alaska
Alaska
Alaska is the largest state in the United States by area. It is situated in the northwest extremity of the North American continent, with Canada to the east, the Arctic Ocean to the north, and the Pacific Ocean to the west and south, with Russia further west across the Bering Strait...
and Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
to make the Refuge home for six months. Here they mingle with thousands of other visiting waterfowl, waterbirds and shorebirds making the Refuge a true winter phenomenon.
The Refuge also provides important breeding habitat for Swainson’s hawks
Swainson's Hawk
The Swainson's Hawk , is a large buteo hawk of the Falconiformes, sometimes separated in the Accipitriformes like its relatives. This species was named after William Swainson, a British naturalist...
, tri-colored blackbirds, marsh wren
Marsh Wren
The Marsh Wren is a small North American songbird of the wren family. It is sometimes called Long-billed Marsh Wren to distinguish it from the Sedge Wren, also known as Short-billed Marsh Wren....
s, mallards, gadwall, cinnamon teal, and burrowing owl
Burrowing Owl
The Burrowing Owl is a tiny but long-legged owl found throughout open landscapes of North and South America. Burrowing Owls can be found in grasslands, rangelands, agricultural areas, deserts, or any other open dry area with low vegetation. They nest and roost in burrows, such as those excavated...
s. Tri-colored blackbirds, a colonial-nesting songbird, breed in colonies of over 25,000 pairs. Coyotes, ground squirrels, desert cottontail rabbits, beaver
Beaver
The beaver is a primarily nocturnal, large, semi-aquatic rodent. Castor includes two extant species, North American Beaver and Eurasian Beaver . Beavers are known for building dams, canals, and lodges . They are the second-largest rodent in the world...
s, and long-tailed weasel
Long-tailed Weasel
The long-tailed weasel , also known as the bridled weasel or big stoat is a species of mustelid distributed from southern Canada throughout all the United States and Mexico, southward through all of Central America and into northern South America.-Evolution:The long-tailed weasel is the product of...
s can also be seen year-round.
Vernal pools are another type of wetland found on the Merced NWR. These special pools form when natural shallow depressions underlaid with clay soils fill with winter rainwater. The pools come to life as they fill with water: fairy
Fairy shrimp
Anostraca is one of the four orders of crustaceans in the class Branchiopoda; its members are also known as fairy shrimp. They are usually long . Most species have 20 body segments, bearing 11 pairs of leaf-like phyllopodia , and the body lacks a carapace...
and tadpole shrimp emerge from cysts embedded in the soils the previous year. The endangered tiger salamander, along with other amphibians lay eggs and rear tadpoles. The vast number of aquatic invertebrates found in these pools provides a food source for wintering and migrating birds as they prepare for the long flight north to their breeding grounds.
As spring arrives and the water in the vernal pools evaporates, wildflowers – such as goldfields
Gold mining
Gold mining is the removal of gold from the ground. There are several techniques and processes by which gold may be extracted from the earth.-History:...
, purple owl's clover, and butter-and-egg
Orobanchaceae
Orobanchaceae, the broomrape family, is a family of flowering plants of the order Lamiales, with about 90 genera and more than 2000 species. Many of these genera were formerly included in the family Scrophulariaceae sensu lato...
– germinate in colorful patterns of thick rings or halos around the pool basins. Once the vernal pools have dried out, Downingia
Downingia
Downingia is a genus of 13 annual plants native to western North America and Chile. Commonly known as "calicoflowers", they are notable for forming mass displays of small but colorful blooms around vernal pools...
and Colusa
Colusa
-Places:*Colusa, California, county seat of Colusa County*Colusa County, California*Colusa County Airport, California*Colusa County Courthouse, California*Colusa, Illinois*Colusa National Wildlife Refuge, California*Colusa Rancheria, California...
grass, a rare California species, appear in the parched basins. This annual coloring led John Muir
John Muir
John Muir was a Scottish-born American naturalist, author, and early advocate of preservation of wilderness in the United States. His letters, essays, and books telling of his adventures in nature, especially in the Sierra Nevada mountains of California, have been read by millions...
to describe the valley floor as the “floweriest part of the world” he had seen.
In addition to managing natural habitats, the Merced NWR contains approximately 300 acres (1.2 km²) of cultivated corn and winter wheat crops and over 500 acres (2 km²) of irrigated pasture for wildlife. Not only do these managed agricultural areas provide important sources of nutrition (carbohydrates) to the tens of thousands of arctic-nesting geese and Sandhill cranes that make Merced County their winter home, they also help ensure that the birds will have adequate nutrient stores to make the long migration to their northern breeding grounds. Local farmers, under agreements with the Refuge, oversee the ground preparation, seeding, and irrigation of these croplands. The Refuge incorporates a livestock grazing program that works in partnership with local ranchers and farmers. Grazing cattle and sheep is a management tool used by the Refuge to help control invasive weeds, provide and maintain short stature grasslands for goose grazing, and encourage native grasslands to thrive
San Joaquin River National Wildlife Refuge
The San Joaquin River National Wildlife Refuge located in Stanislaus County encompasses over 7000 acres (28.3 km²) of riparian woodlands, wetlands and grasslands that host a diversity of wildlife native to California’s Central Valley. The Refuge is situated where three major rivers (San JoaquinSan Joaquin River
The San Joaquin River is the largest river of Central California in the United States. At over long, the river starts in the high Sierra Nevada, and flows through a rich agricultural region known as the San Joaquin Valley before reaching Suisun Bay, San Francisco Bay, and the Pacific Ocean...
, Tuolumne
Tuolumne River
The Tuolumne River is a California river that flows nearly from the central Sierra Nevada to the San Joaquin River in the Central Valley...
and Stanislaus) join providing a key travel corridor for wildlife. The refuge was established in 1987 under the Endangered Species Act
Endangered Species Act
The Endangered Species Act of 1973 is one of the dozens of United States environmental laws passed in the 1970s. Signed into law by President Richard Nixon on December 28, 1973, it was designed to protect critically imperiled species from extinction as a "consequence of economic growth and...
and the Migratory Bird Treaty Act of 1918
Migratory Bird Treaty Act of 1918
The Migratory Bird Treaty Act of 1918 , codified at , is a United States federal law, at first enacted in 1916 in order to implement the convention for the protection of migratory birds between the United States and Great Britain...
.
The Refuge has played a major role in the recovery of Aleutian cackling geese
Aleutian Cackling Goose
The Aleutian Cackling Goose , formerly known as the Aleutian Canada Goose , is small subspecies of Cackling Goose averaging 1700 to 2100 grams....
by serving as a key wintering area and continues to be of major importance to this species. By 1975, the total population was under 1,000 geese; however, removing nest predators (non-native introduced foxes) from the breeding grounds in Alaska’s Aleutian Islands and improving wintering habitat resulted in its delisting as an endangered species and a population well over 100,000 and growing. Restoring wetlands and providing grasslands and croplands at this refuge has provided ideal wintering habitat for the geese.
It is estimated that 95 percent of the San Joaquin Valley’s riparian woodlands were lost during the last century due to changing land uses; however, this refuge is in the process of restoring this critical habitat. Within the borders of the San Joaquin NWR is one of California’s largest riparian forest restoration projects: 400,000 native trees such as willows, cottonwoods and oaks have been planted across 1700 acres (7 km²) of river floodplain creating the largest block of contiguous riparian woodland in the San Joaquin Valley. This important riparian woodland habitat is host to many rare animals. Swainson’s hawks nest in the canopy of tall cottonwood trees. Herons and cormorants form communal nesting colonies within the tops of the large oaks. Endangered riparian brush rabbits have been re-introduced to this restored habitat from captive-reared populations. These woodlands also support a diversity of breeding songbirds including grosbeak
Grosbeak
Grosbeak is a form taxon containing several species of seed-eating passerine birds with large beaks. Although they all belong to the superfamily Passeroidea, they are not a natural group but rather a polyphyletic assemblage of distantly related songbirds....
s, oriole
Oriole
Orioles are colourful Old World passerine birds in the genus Oriolus, the namesake of the corvoidean family Oriolidae. They are not related to the New World orioles, which are icterids and, belonging to the superfamily Passeroidea songbirds, are quite unrelated to the true orioles.The orioles are...
s, flycatcher
Flycatcher
There are various families of bird termed flycatchers:* The Old World flycatchers, Muscicapidae* The Tyrant flycatchers, Tyrannidae* The Monarch flycatchers, Dicruridae* The Silky-flycatchers, Ptilogonatidae* The Fairy flycatchers, Stenostiridae...
s, warbler
Warbler
There are a number of Passeriformes called "warblers". They are not particularly closely related, but share some characteristics, such as being fairly small, vocal and insectivorous....
s, as well as least Bell's Vireo
Bell's Vireo
The Bell's Vireo is a small North American songbird. It is 4-3/4 to 5 inches in length, dull olive-gray above and whitish below...
s – a threatened species which last nested in the San Joaquin Valley over 50 years ago.
A wildlife viewing platform along Beckwith Road is a favorite location for viewing the Aleutian cackling geese along with other waterbirds from October through March.
Grasslands Wildlife Management Area
The Grasslands Wildlife Management Area (GWMA) was established by the U.S. Fish and Wildlife Service in 1979 and is composed of privately owned lands on which perpetual conservation easements have been purchased. These easements preserve wetland and grassland habitats and prevent conversion to croplands or other uses not compatible with migratory bird and other wildlife values. Daily management operations remain under the landowner's control. The majority of easement properties are wetlands managed for waterfowl hunting. From 1979 to-date, over 65000 acres (263 km²) have been placed under conservation easements.The GWMA is located in western Merced County, California, within the San Joaquin River basin and supports the largest remaining block of contiguous wetlands in the Central Valley. It is divided into an eastern and western division separated by the San Joaquin River. In the heart of the western division is the Grassland Resource Conservation District (GRCD), an area of 70000 acres (283.3 km²) of private wetlands and associated grasslands, and over 30600 acres (124 km²) of federal National Wildlife Refuges and state Wildlife Management Areas.
These private wetlands constitute 30% of the remaining wetlands in California's Central Valley and are extremely important to Pacific Flyway waterfowl populations. Over 60 million duck use-day and 3 million goose use-days occur annually in the GWMA. The wetlands support diverse habitats including seasonally flooded marshlands, semi-permanent marsh, riparian habitat, wet meadows, vernal pools, native uplands, pastures, and native grasslands. This habitat diversity supports raptors, shorebirds, wading birds, and other wildlife species. Several federal and state listed, endangered, and threatened plants and animals are present in the area and benefit by the habitat protection provided by the easement program.