LeConte's Thrasher
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LeConte's thrasher (''Toxostoma lecontei'') is a pale bird found in the
southwestern United States The Southwestern United States, also known as the American Southwest or simply the Southwest, is a geographic and cultural list of regions of the United States, region of the United States that includes Arizona and New Mexico, along with adjacen ...
and northwestern
Mexico Mexico, officially the United Mexican States, is a country in North America. It is the northernmost country in Latin America, and borders the United States to the north, and Guatemala and Belize to the southeast; while having maritime boundar ...
. It prefers to live in
desert A desert is a landscape where little precipitation occurs and, consequently, living conditions create unique biomes and ecosystems. The lack of vegetation exposes the unprotected surface of the ground to denudation. About one-third of the la ...
s with very little
vegetation Vegetation is an assemblage of plants and the ground cover they provide. It is a general term, without specific reference to particular Taxon, taxa, life forms, structure, Spatial ecology, spatial extent, or any other specific Botany, botanic ...
, where it blends in with the sandy soils. LeConte's thrashers are nonmigratory birds that reside in the same territory annually. Although the species has been decreasing in certain areas of its range, in particular California, it still is abundant enough to not be considered for vulnerable status. These birds are terrestrial and only fly occasionally. Both sexes are heavily involved in the nest building, incubating, and brooding process, though each alternates with primary responsibility of the tasks. LeConte's thrashers frequently compete with species such as the
northern mockingbird The northern mockingbird (''Mimus polyglottos'') is a mockingbird commonly found in North America, of the family Mimidae. The species is also found in some parts of the Caribbean, as well as on the Hawaiian Islands. It is typically a permanent B ...
,
loggerhead shrike The loggerhead shrike (''Lanius ludovicianus'') is a passerine bird in the family Laniidae. It is the only member of the shrike family endemic to North America; the related northern shrike (''L. borealis'') occurs north of its range, however it ...
and
greater roadrunner The greater roadrunner (''Geococcyx californianus'') is a long-legged bird in the cuckoo family, Cuculidae, from the Aridoamerica region in the Southwestern United States and Mexico. The scientific name means "Californian earth-cuckoo". Along wi ...
, as well as being potential prey for the latter.


Taxonomy

LeConte's thrasher is named after Dr. John Lawrence LeConte, an
entomologist Entomology (from Ancient Greek ἔντομον (''éntomon''), meaning "insect", and -logy from λόγος (''lógos''), meaning "study") is the branch of zoology that focuses on insects. Those who study entomology are known as entomologists. In ...
who eventually became president of the
American Association for the Advancement of Science The American Association for the Advancement of Science (AAAS) is a United States–based international nonprofit with the stated mission of promoting cooperation among scientists, defending scientific freedom, encouraging scientific responsib ...
. There are two subspecies: ''T.l. lecontei'' (Lawrence, 1851) – range is from southwestern United States (south central and eastern
California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...
, southwest
Utah Utah is a landlocked state in the Mountain states, Mountain West subregion of the Western United States. It is one of the Four Corners states, sharing a border with Arizona, Colorado, and New Mexico. It also borders Wyoming to the northea ...
, and south central
Arizona Arizona is a U.S. state, state in the Southwestern United States, Southwestern region of the United States, sharing the Four Corners region of the western United States with Colorado, New Mexico, and Utah. It also borders Nevada to the nort ...
) to northwestern Mexico (north east
Baja California Baja California, officially the Free and Sovereign State of Baja California, is a state in Mexico. It is the northwesternmost of the 32 federal entities of Mexico. Before becoming a state in 1952, the area was known as the North Territory of B ...
and northwest
Sonora Sonora (), officially Estado Libre y Soberano de Sonora (), is one of the 31 states which, along with Mexico City, comprise the Administrative divisions of Mexico, Federal Entities of Mexico. The state is divided into Municipalities of Sonora, 72 ...
). ''T.l. arenicola'' (Anthony, 1897) Rosalia thrasher; west coast of Baja California. ''T.l. arenicola'' has been proposed by the
American Ornithologists Union The American Ornithological Society (AOS) is an ornithological organization based in the United States. The society was formed in October 2016 by the merger of the American Ornithologists' Union (AOU) and the Cooper Ornithological Society. Its ...
as separate species, and treated as a separate species by other authors. and a name of Vizcaino thrasher if it becomes official. ''T.l. arenicola'' still is treated as a subspecies of ''lecontei'' by some authors, however. A proposed race ''T.c. macmillanorum'' only exhibits minor differences in plumage from ''T.l. lecontei'' (such as a darker crown and lighter flanks), but is not justified by biochemical or morphological grounds. One study suggested that the
phylogeographic Phylogeography is the study of the historical processes that may be responsible for the past to present geographic distributions of genealogical lineages. This is accomplished by considering the geographic distribution of individuals in light of ge ...
structure of the LeConte's is consistent with both its geographic distribution and genetics, with the Vizcaíno Desert in Baja California acting as a barrier initiating
allopatric speciation Allopatric speciation () – also referred to as geographic speciation, vicariant speciation, or its earlier name the dumbbell model – is a mode of speciation that occurs when biological populations become geographically isolated from ...
. The two closest living relatives of LeConte's thrasher, the
California thrasher The California thrasher (''Toxostoma redivivum'') is a large member of family Mimidae found primarily in chaparral habitat in California in the United States and Baja California in Mexico. It is the only species of the genus ''Toxostoma'' throu ...
and the crissal thrasher, form as the ''lecontei'' group. The similarities with these three species contrasted with other ''Toxostoma'' thrashers, in particular the sickle-shaped bill, longer legs and smaller wings indicated its adaption to a preference to running and digging for food.


Description

LeConte's thrasher weighs from and are , and there is no
sexual dimorphism Sexual dimorphism is the condition where sexes of the same species exhibit different Morphology (biology), morphological characteristics, including characteristics not directly involved in reproduction. The condition occurs in most dioecy, di ...
within the species. Their wings are typical of birds that are sedentary, as they are short and rounded. There are noted differences among the subspecies. The crown, back, shoulders, and rump of ''T.c. lecontei'' possess a sandy pale-gray color. The primaries and secondaries are grayish brown. The rectrices are of a darker gray brown that contrasts with the plumage. Lores and ear-coverts are a mottled gray brown. The throat is an off-whitish color of a darker stripe. The chest and belly is puffy gray, and the vent and uppertail coverts are of a warmer tint in contrast to the palish chest and belly. The underwing is both gray and buff, with a brown-chestnut iris, a black-sickle shaped bill, and legs that are nearly black. ''T.l. arenicola'' has a darker chest and underparts and a shorter tail. In its juvenile stages, the thrasher is darker brown, and its feathers looser and fluffy in appearance, especially on the vent.


Range and habitat

This bird ranges from California as far west as the San Joaquin Valley through southern
Nevada Nevada ( ; ) is a landlocked state in the Western United States. It borders Oregon to the northwest, Idaho to the northeast, California to the west, Arizona to the southeast, and Utah to the east. Nevada is the seventh-most extensive, th ...
and southwestern
Utah Utah is a landlocked state in the Mountain states, Mountain West subregion of the Western United States. It is one of the Four Corners states, sharing a border with Arizona, Colorado, and New Mexico. It also borders Wyoming to the northea ...
and central and southern Arizona, and is a resident species throughout its range. It resides in some of the harshest climates in its region, including the
Sonoran Desert The Sonoran Desert () is a hot desert and ecoregion in North America that covers the northwestern Mexican states of Sonora, Baja California, and Baja California Sur, as well as part of the Southwestern United States (in Arizona and California). It ...
and the
San Joaquin Valley The San Joaquin Valley ( ; Spanish language in California, Spanish: ''Valle de San Joaquín'') is the southern half of California's Central Valley (California), Central Valley. Famed as a major breadbasket, the San Joaquin Valley is an importa ...
, and where annual rainfall only averages 4 to 20 cm. The typical desert habitat consists of dunes, alluvial fans, and flat to gently rolling hills with shallow washes with sparse vegetation. The vegetation that it may utilize includes low vegetation such as
saltbush Saltbush is a vernacular plant name that most often refers to ''Atriplex'', a genus of about 250 plants distributed worldwide from subtropical to subarctic regions. ''Atriplex'' species are native to Australia, North and South America, and Eurasia. ...
,
creosote Creosote is a category of carbonaceous chemicals formed by the distillation of various tars and pyrolysis of plant-derived material, such as wood, or fossil fuel. They are typically used as preservatives or antiseptics. Some creosote types w ...
, cholla cacti, and
Mojave yucca ''Yucca schidigera'', also known as the Mojave yucca or Spanish dagger, is a perennial plant in the asparagus family Asparagaceae, native to the southwestern United States and northwestern Mexico. It is most common in the Mojave Desert, but also ...
. The range of altitude spans as low as 80 m below sea level (in
Death Valley Death Valley is a desert valley in Eastern California, in the northern Mojave Desert, bordering the Great Basin Desert. It is thought to be the Highest temperature recorded on Earth, hottest place on Earth during summer. Death Valley's Badwat ...
) to as high as 1,600 m, although 500 m above sea level is the average. It does not generally coexist with other thrashers due to its habitat, but does overlap breeding ranges and general habitat with the
California thrasher The California thrasher (''Toxostoma redivivum'') is a large member of family Mimidae found primarily in chaparral habitat in California in the United States and Baja California in Mexico. It is the only species of the genus ''Toxostoma'' throu ...
in the higher desert regions of its range. The thrasher has had its population decline in certain regions of its range, notably the
Coachella Coachella (officially called the Coachella Valley Music and Arts Festival and sometimes known as Coachella Festival) is an annual music festival, music and arts festival held at the Empire Polo Club in Indio, California, in the Coachella Valle ...
, Imperial and the
San Joaquin Valley The San Joaquin Valley ( ; Spanish language in California, Spanish: ''Valle de San Joaquín'') is the southern half of California's Central Valley (California), Central Valley. Famed as a major breadbasket, the San Joaquin Valley is an importa ...
regions. Major reasons for its decline include urbanization, cultivation of land for
livestock Livestock are the Domestication, domesticated animals that are raised in an Agriculture, agricultural setting to provide labour and produce diversified products for consumption such as meat, Egg as food, eggs, milk, fur, leather, and wool. The t ...
, oil and gas development, and fire with the increase of
invasive species An invasive species is an introduced species that harms its new environment. Invasive species adversely affect habitats and bioregions, causing ecological, environmental, and/or economic damage. The term can also be used for native spec ...
of grasses. Off-road vehicle use is a minor factor, while military operations conducted in the region have been considered, but not properly researched. However, there are apparent areas of suitable acreage for the thrasher that have not been utilized, and its population in undisturbed regions appear to be more stable. Although the thrasher has relatively small numbers on a worldwide scale for a passerine, and has been listed as a species of concern in the state of California, its large range overall justifies its status as least concern.


Behavior

This thrasher is a highly terrestrial bird, and is only seen flying when nest building or feeding its young. It runs at a surprisingly fast pace, even at speeds to outpace a trotting horse. When it does run, its tail is generally held upward, exposing its buffy crissum. LeConte's thrasher is a ground forager, and will dig small pits in leaf litter or soil to find its prey. It is a monogamous species, and generally seen in pairs, and juveniles may form small parties from two to eight birds.


Song

The song is a large, prolonged outpouring of warbled phrases that can be repeated two or several times and can be heard from considerable distances, which is typical of the genus ''Toxostoma''. The song starts softly, then increases in volume, and has a more measured delivery than that of the crissal thrasher. The song bouts have been compared to curve-billed thrashers, but are higher pitched and marked by clear intervals. The song is generally uttered from an exposed perch, and is generally heard either in the morning or in the evening, though it has been heard at night. Females also sing on occasion, in a manner similar to juvenile male LeConte's. Calls include a short whistle note ''suuuweeee'', ''hew-eep'' or ''pooh-ip'', along with the double-noted whistling distress call.


Diet

The diet is omnivorous, and includes
arthropods Arthropods ( ) are invertebrates in the phylum Arthropoda. They possess an arthropod exoskeleton, exoskeleton with a cuticle made of chitin, often Mineralization (biology), mineralised with calcium carbonate, a body with differentiated (Metam ...
such as beetles, scorpions, spiders, grasshoppers, butterflies, moth larvae, and small lizards and snakes. Eggs are also part of its diet, including those of its own species. Plant consumption includes seeds and berries. The LeConte's conserve water as an adaptation to their arid habitat and obtain what they need from their food. While they generally do not have to drink, there has been one recorded instance of such an event.


Breeding

The singing season typically begins in mid-autumn and peaks around late December and early January, when nest building begins. The nests are generally of a bulky build, with outer layer of twigs, a middle layer of twigs, grasses, and rootlets, and an inner layer of insulating materials such as fuzzy plant seeds, leaves or flowers. Feathers and artificial material have been used as well, but these instances are rare. Dense and thorny shrubs such as the saltbush are preferred sites, although artificial sites such as abandoned vehicles and heights as high as 2.4 m with smoke trees have been used when the general distance of nests off the ground are usually only half as low. Both sexes take part in nest building, although the participation of the male varies. Nest fidelity is generally observed with the species until one of the mates die. The territories of the nesting pairs may be adjacent to one another due to food sources, although conflicts are rarely had. The egg dates generally range from February to the end of May in California, and in the Sonoran region from December to April, though dates have been listed as early as late January and as late as the latter part of June. The clutch size ranges from 2 to 5 eggs, but the number is generally 3–4. The eggs are large-sized and bluish green that may either contain various degrees of brown spotting or no markings. The eggs are generally laid once a day and incubation begins once the last egg is laid, and lasts from 14 to 20 days. The male generally provides the food for the female, as well as food for the young during the brooding stages. The female is more likely to incubate during at night, however. If the nest is destroyed or preyed upon, a new one is generally built, as they can have up to three broods during the reproductive season. The young are fed by both parents during the fledgling period, which can span from 12 to 20 days, and can be continued to be fed after for 15 to 18 days afterward, especially if the female is brooding the next clutch. At around 30 days old, the fledglings disperse, and may form small groups.


Predators and competitors

These birds defend their territory year-round, but males are generally less territorial in the summer months during molting and the fledgling dispersals. Males may give a visual display to intruding males by employing a head down position, showing off their crissum (the undertail
coverts A covert feather or tectrix on a bird is one of a set of feathers, called coverts (or ''tectrices''), which cover other feathers. The coverts help to smooth airflow over the wings and tail. Ear coverts The ear coverts are small feathers behind t ...
surrounding the
cloaca A cloaca ( ), : cloacae ( or ), or vent, is the rear orifice that serves as the only opening for the digestive (rectum), reproductive, and urinary tracts (if present) of many vertebrate animals. All amphibians, reptiles, birds, cartilagin ...
) while simultaneously disappearing into a bush head first in a slow motion. Their territories are most actively defended from early December to early February. Potential competitors for food and nesting sites include the
northern mockingbird The northern mockingbird (''Mimus polyglottos'') is a mockingbird commonly found in North America, of the family Mimidae. The species is also found in some parts of the Caribbean, as well as on the Hawaiian Islands. It is typically a permanent B ...
, sage thrasher,
loggerhead shrike The loggerhead shrike (''Lanius ludovicianus'') is a passerine bird in the family Laniidae. It is the only member of the shrike family endemic to North America; the related northern shrike (''L. borealis'') occurs north of its range, however it ...
, house finch, black-throated sparrow, cactus wren, and the
greater roadrunner The greater roadrunner (''Geococcyx californianus'') is a long-legged bird in the cuckoo family, Cuculidae, from the Aridoamerica region in the Southwestern United States and Mexico. The scientific name means "Californian earth-cuckoo". Along wi ...
. They may share the same nesting shrub or tree with their competitors, such as the loggerhead shrike. They are rarely victims of
cowbird Cowbirds are birds belonging to the genus ''Molothrus'' in the family Icteridae. They are of New World origin, but some species not native to North America are invasive there, and are obligate brood parasites, laying their eggs in the nests of o ...
parasitism Parasitism is a close relationship between species, where one organism, the parasite, lives (at least some of the time) on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The en ...
. LeConte's thrasher has been recorded being victimized by the bronzed cowbird in a least one instance, but not by the
brown-headed cowbird The brown-headed cowbird (''Molothrus ater'') is a small, obligate brood parasitic icterid native to temperate and subtropical North America. It is a permanent resident in the southern parts of its range; northern birds migrate to the souther ...
. However, when 11 brown-headed cowbird eggs were placed in the thrasher's nest in an experiment, they were accepted. Some of the predators of the eggs, young, and adults of this species include
birds of prey Birds of prey or predatory birds, also known as (although not the same as) raptors, are hypercarnivorous bird species that actively predation, hunt and feed on other vertebrates (mainly mammals, reptiles and smaller birds). In addition to speed ...
, greater roadrunners,
antelope squirrel Antelope squirrels or antelope ground squirrels of the genus ''Ammospermophilus'' are sciurids found in the desert and dry scrub areas of the southwestern United States and northern Mexico. They are a type of ground squirrel and are able to resi ...
s,
domestic cat The cat (''Felis catus''), also referred to as the domestic cat or house cat, is a small Domestication, domesticated carnivorous mammal. It is the only domesticated species of the family Felidae. Advances in archaeology and genetics have sh ...
s,
dog The dog (''Canis familiaris'' or ''Canis lupus familiaris'') is a domesticated descendant of the gray wolf. Also called the domestic dog, it was selectively bred from a population of wolves during the Late Pleistocene by hunter-gatherers. ...
s,
coyotes The coyote (''Canis latrans''), also known as the American jackal, prairie wolf, or brush wolf, is a species of canine native to North America. It is smaller than its close relative, the gray wolf, and slightly smaller than the closely relat ...
, and various
snake Snakes are elongated limbless reptiles of the suborder Serpentes (). Cladistically squamates, snakes are ectothermic, amniote vertebrates covered in overlapping scales much like other members of the group. Many species of snakes have s ...
species.


References


External links

* * {{Taxonbar, from=Q3181161
Le Conte's thrasher LeConte's thrasher (''Toxostoma lecontei'') is a pale bird found in the southwestern United States and northwestern Mexico. It prefers to live in deserts with very little vegetation, where it blends in with the sandy soils. LeConte's thrashers ar ...
Le Conte's thrasher LeConte's thrasher (''Toxostoma lecontei'') is a pale bird found in the southwestern United States and northwestern Mexico. It prefers to live in deserts with very little vegetation, where it blends in with the sandy soils. LeConte's thrashers ar ...
Endemic birds of Southwestern North America Fauna of the Colorado Desert Fauna of the Lower Colorado River Valley Fauna of the Yuma Desert Fauna of the Sonoran Desert Birds of Mexico
Le Conte's thrasher LeConte's thrasher (''Toxostoma lecontei'') is a pale bird found in the southwestern United States and northwestern Mexico. It prefers to live in deserts with very little vegetation, where it blends in with the sandy soils. LeConte's thrashers ar ...
Le Conte's thrasher LeConte's thrasher (''Toxostoma lecontei'') is a pale bird found in the southwestern United States and northwestern Mexico. It prefers to live in deserts with very little vegetation, where it blends in with the sandy soils. LeConte's thrashers ar ...