Merced National Wildlife Refuge
Encyclopedia
The Merced National Wildlife Refuge encompasses 10262 acres (41.5 km²) of wetland
s, native grassland
s, 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 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 hawk
s, tri-colored blackbirds, marsh wren
s, mallard
s, gadwall
, cinnamon teal
, and burrowing owl
s. Tri-colored blackbirds, a colonial-nesting songbird
, breed in colonies of over 25,000 pairs. Coyote
s, ground squirrel
s, desert cottontail
rabbits, beaver
, and long-tailed weasel
s can also be seen year-round.
Vernal pools are another type of wetland found on the Merced National Wildlife Refuge. 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 cyst
s embedded in the soils the previous year. The endangered
tiger salamander
, along with other amphibians, lays 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 goldfield
s, purple owl's clover, and butter-and-eggs
– 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 National Wildlife Refuge 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 (carbohydrate
s) 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 weed
s, provide and maintain short stature grasslands for goose grazing, and encourage native grasslands to thrive.
Wetland
A wetland is an area of land whose soil is saturated with water either permanently or seasonally. Wetlands are categorised by their characteristic vegetation, which is adapted to these unique soil conditions....
s, native grassland
Grassland
Grasslands are areas where the vegetation is dominated by grasses and other herbaceous plants . However, sedge and rush families can also be found. Grasslands occur naturally on all continents except Antarctica...
s, vernal pools, and riparian areas. It was established in 1951 under the Lea Act to attract wintering waterfowl
Waterfowl
Waterfowl are certain wildfowl of the order Anseriformes, especially members of the family Anatidae, which includes ducks, geese, and swans....
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 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
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...
. 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 hawk
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...
s, 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, 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....
s, 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...
, 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...
, 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
Songbird
A songbird is a bird belonging to the suborder Passeri of the perching birds . Another name that is sometimes seen as scientific or vernacular name is Oscines, from Latin oscen, "a songbird"...
, breed in colonies of over 25,000 pairs. Coyote
Coyote
The coyote , also known as the American jackal or the prairie wolf, is a species of canine found throughout North and Central America, ranging from Panama in the south, north through Mexico, the United States and Canada...
s, ground squirrel
Ground squirrel
The ground squirrels are members of the squirrel family of rodents which generally live on or in the ground, rather than trees. The term is most often used for the medium-sized ground squirrels, as the larger ones are more commonly known as marmots or prairie dogs, while the smaller and less...
s, desert cottontail
Desert Cottontail
The Desert Cottontail , also known as Audubon's Cottontail, is a New World cottontail rabbit, a member of the family Leporidae....
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...
, 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 National Wildlife Refuge. 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 cyst
Cyst
A cyst is a closed sac, having a distinct membrane and division on the nearby tissue. It may contain air, fluids, or semi-solid material. A collection of pus is called an abscess, not a cyst. Once formed, a cyst could go away on its own or may have to be removed through surgery.- Locations :* Acne...
s embedded in the soils the previous year. The endangered
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...
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:...
, along with other amphibians, lays 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 goldfield
Lasthenia
Lasthenia, commonly known as goldfields, is a genus of the botanical family Asteraceae. The genus is named after Lasthenia, a cross-dressing female pupil of the ancient Greek philosopher Plato.-Description:...
s, purple owl's clover, and butter-and-eggs
Butter-and-eggs
Butter-and-eggs may refer to:*Butter-and-eggs, one of the common names for Linaria vulgaris, a species of toadflax*Butter and eggs, one of the common names for Triphysaria eriantha, a species in Orobanchaceae, the broomrape family....
– 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 National Wildlife Refuge contains approximately 300 acres (1.2 km²) of cultivated corn
Maize
Maize known in many English-speaking countries as corn or mielie/mealie, is a grain domesticated by indigenous peoples in Mesoamerica in prehistoric times. The leafy stalk produces ears which contain seeds called kernels. Though technically a grain, maize kernels are used in cooking as a vegetable...
and winter wheat
Wheat
Wheat is a cereal grain, originally from the Levant region of the Near East, but now cultivated worldwide. In 2007 world production of wheat was 607 million tons, making it the third most-produced cereal after maize and rice...
crops and over 500 acres (2 km²) of irrigated pasture for wildlife. Not only do these managed agricultural areas provide important sources of nutrition (carbohydrate
Carbohydrate
A carbohydrate is an organic compound with the empirical formula ; that is, consists only of carbon, hydrogen, and oxygen, with a hydrogen:oxygen atom ratio of 2:1 . However, there are exceptions to this. One common example would be deoxyribose, a component of DNA, which has the empirical...
s) 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
Grazing
Grazing generally describes a type of feeding, in which a herbivore feeds on plants , and also on other multicellular autotrophs...
cattle
Cattle
Cattle are the most common type of large domesticated ungulates. They are a prominent modern member of the subfamily Bovinae, are the most widespread species of the genus Bos, and are most commonly classified collectively as Bos primigenius...
and sheep is a management tool used by the Refuge to help control invasive weed
Weed
A weed in a general sense is a plant that is considered by the user of the term to be a nuisance, and normally applied to unwanted plants in human-controlled settings, especially farm fields and gardens, but also lawns, parks, woods, and other areas. More specifically, the term is often used to...
s, provide and maintain short stature grasslands for goose grazing, and encourage native grasslands to thrive.