The willow flycatcher (''Empidonax traillii'') is a small insect-eating,
neotropical
The Neotropical realm is one of the eight biogeographic realms constituting Earth's land surface. Physically, it includes the tropical terrestrial ecoregions of the Americas and the entire South American temperate zone.
Definition
In bioge ...
migrant
bird
Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweigh ...
of the
tyrant flycatcher
The tyrant flycatchers (Tyrannidae) are a family of passerine birds which occur throughout North and South America. They are considered the largest family of birds known to exist in the world, with more than 400 species. They are the most dive ...
family. There are four subspecies of the willow flycatcher currently recognized, all of which breed in North America (including three subspecies that breed in California).
[ ''Empidonax'' flycatchers are almost impossible to tell apart in the field so biologists use their songs to distinguish between them.][ The ]binomial
Binomial may refer to:
In mathematics
*Binomial (polynomial), a polynomial with two terms
* Binomial coefficient, numbers appearing in the expansions of powers of binomials
*Binomial QMF, a perfect-reconstruction orthogonal wavelet decomposition
...
commemorates the Scottish zoologist Thomas Stewart Traill
Thomas Stewart Traill (29 October 1781 – 30 July 1862) was a British physician, chemist, meteorologist, zoologist and scholar of medical jurisprudence. He was the grandfather of the physicist, meteorologist and geologist Robert Traill Omon ...
.
Description and ecology
Adults have brown-olive upperparts, darker on the wings and tail, with whitish underparts; they have an indistinct white eye ring, white wing bars and a small bill. The breast is washed with olive-gray. The upper part of the bill is gray; the lower part is orangish. At one time, this bird and the alder flycatcher (''Empidonax alnorum'') were considered to be a single species, Traill's flycatcher. The willow and alder flycatchers were considered the same species until the 1970s. Their song is the only reliable method to tell them apart in the field .[
Their breeding habitat is ]deciduous
In the fields of horticulture and Botany, the term ''deciduous'' () means "falling off at maturity" and "tending to fall off", in reference to trees and shrubs that seasonally shed leaves, usually in the autumn; to the shedding of petals, aft ...
thickets, especially willow
Willows, also called sallows and osiers, from the genus ''Salix'', comprise around 400 speciesMabberley, D.J. 1997. The Plant Book, Cambridge University Press #2: Cambridge. of typically deciduous trees and shrubs, found primarily on moist s ...
s and often near water, across the United States and southern Canada
Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tot ...
. They make a cup nest
A bird nest is the spot in which a bird lays and incubates its eggs and raises its young. Although the term popularly refers to a specific structure made by the bird itself—such as the grassy cup nest of the American robin or Eurasian bl ...
in a vertical fork in a shrub or tree.
These neotropical birds migrate to Mexico
Mexico (Spanish: México), officially the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States; to the south and west by the Pacific Ocean; to the southeast by Guatema ...
and Central America
Central America ( es, América Central or ) is a subregion of the Americas. Its boundaries are defined as bordering the United States to the north, Colombia to the south, the Caribbean Sea to the east, and the Pacific Ocean to the west. ...
, and in small numbers as far south as Ecuador
Ecuador ( ; ; Quechua: ''Ikwayur''; Shuar: ''Ecuador'' or ''Ekuatur''), officially the Republic of Ecuador ( es, República del Ecuador, which literally translates as "Republic of the Equator"; Quechua: ''Ikwadur Ripuwlika''; Shuar: ''Eku ...
in South America
South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the southe ...
, often selecting winter habitat near water. Willow flycatchers travel approximately each way between wintering and breeding areas.[
They wait on a perch near the top of a shrub and fly out to catch insects in flight, also sometimes picking ]insect
Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body ( head, thorax and abdomen), three pairs ...
s from foliage while hovering. They may eat some berries
A berry is a small, pulpy, and often edible fruit. Typically, berries are juicy, rounded, brightly colored, sweet, sour or tart, and do not have a stone or pit, although many pips or seeds may be present. Common examples are strawberries, raspb ...
.
This bird's song is a sneezed ''fitz-bew''. The call is a dry ''whit''.
This bird competes for habitat with the alder flycatcher where their ranges overlap.
Food resources
Willow flycatcher feed on insects, and common hoverflies ''Syritta pipiens
''Syritta pipiens,'' sometimes called the thick-legged hoverfly, is one of the most common species in the insect family Syrphidae. This fly originates from Europe and is currently distributed across Eurasia and North America. They are fast and ...
'' have been found in their fecal samples.
Subspecies
The subspecies are best distinguished from each other by their songs.[ In addition, the four subspecies have significant genetic differences based on mitochondrial DNA analysis.][ Their winter ranges have been elucidated using mitochondrial DNA genetic studies of 172 birds sampled in winter combined with plumage coloration and morphological differences.][
The four subspecies of the willow flycatcher are:][
]
''E. t. brewsteri'' – Little willow flycatcher
The little willow flycatcher (''E.t. brewsteri'') is the Pacific slope subspecies of the willow flycatcher. Described by Oberholser in 1918, it breeds in California from Tulare County[ north along the western side of the Sierra Nevada, and in Oregon and Washington west of the Cascade range.][
]
''E.t. adastus''
The Great Basin/Northern Rockies subspecies of the willow flycatcher (''E. t. adastus'') breeds in California east of the Sierra/Cascade axis, from the Oregon border into Modoc County and possibly into northern Inyo County. Populations at high elevation just east of the Sierra Nevada crest but south of Modoc County are assumed to be ''E. t. brewsteri''. There has been very little study of ''E. t. adastus'' in California.[ It was described by Oberholser in 1932.
]
''E. t. extimus'' – Southwestern willow flycatcher
The southwestern willow flycatcher (''E. t. extimus'') is a federally endangered
An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching and inva ...
subspecies and it is known to be found in Arizona, California, Colorado, Nevada, New Mexico, Texas, and Utah. It was listed in 1995, at which time it was known to breed at only about 75 sites in riparian areas throughout the American southwest. The known breeding population was estimated at between 300 and 500 pairs.[ Breeding occurs from near sea level on the ]Santa Margarita River
The Santa Margarita River which with the addition of what is now Temecula Creek, was formerly known as the Temecula River, is a short intermittent river on the Pacific coast of southern California in the United States, approximately U.S. Geologi ...
to at the South Fork Kern River
The South Fork Kern River is a tributary of the Kern River in the Sierra Nevada of the U.S. state of California. It is one of the southernmost rivers on the western slope of the mountains, and drains a high, relatively dry plateau country of al ...
and at upper San Luis Rey River
The San Luis Rey River is a river in northern San Diego County, California.
The river's headwaters are in the Palomar Mountain Range and Cleveland National Forest, near Palomar Mountain and the Santa Rosa Mountains. The river mouth, on the Pacif ...
in California and to over in Arizona, southwestern Colorado, and north-central New Mexico.
The largest remaining population in California is on the South Fork Kern River, Kern County. In southern California, this subspecies breeds on the San Luis Rey River, at Camp Pendleton
Marine Corps Base Camp Pendleton is the major West Coast base of the United States Marine Corps and is one of the largest Marine Corps bases in the United States. It is on the Southern California coast in San Diego County and is bordered by Oc ...
, the Santa Margarita River and Pilgrim, De Luz, French, and Las Flores creeks; as well as on the Santa Ynez River
The Santa Ynez River is one of the largest rivers on the Central Coast of California. It is long, ArcExplorer GIS data viewer. flowing from east to west through the Santa Ynez Valley, reaching the Pacific Ocean at Surf, near Vandenberg Space Fo ...
. In 1996, breeding was confirmed along the Arizona side of the lower Colorado River
The Colorado River ( es, Río Colorado) is one of the principal rivers (along with the Rio Grande) in the Southwestern United States and northern Mexico. The river drains an expansive, arid drainage basin, watershed that encompasses parts of ...
at Lake Mead Delta and at Topock Marsh. Examination of museum specimens of 578 migrating and wintering ''E. t. extimus'' indicating that Guatemala
Guatemala ( ; ), officially the Republic of Guatemala ( es, República de Guatemala, links=no), is a country in Central America. It is bordered to the north and west by Mexico; to the northeast by Belize and the Caribbean; to the east by H ...
to Costa Rica
Costa Rica (, ; ; literally "Rich Coast"), officially the Republic of Costa Rica ( es, República de Costa Rica), is a country in the Central American region of North America, bordered by Nicaragua to the north, the Caribbean Sea to the no ...
constitutes the main winter range. This species is experiencing population declines throughout the Southwest due to habitat loss/alteration and invasive species.[
Saltcedar ('']Tamarix ramosissima
''Tamarix ramosissima'', commonly known as saltcedar salt cedar, or tamarisk, is a deciduous arching shrub with reddish stems, feathery, pale green foliage, and characteristic small pink flowers.
The cultivar 'Pink Cascade' (dark pink flowered) ...
)'' is an invasive species found throughout the Southwest and has replaced essential vegetation, by outcompeting native species, in riparian areas where the Southwest Willow flycatcher is found, which could be a contributing factor in this species decline. In two sites, one in Arizona and the other in New Mexico, native trees were able to replace patches of tamarix and populations of willow flycatchers increased. It was documented that in these sites 90% of the willow flycatcher's nests were found in native vegetation, only 10% were in mixed vegetation (native species and Saltcedar) and few were in areas dominated by Saltcedar. However, it's important to note that because willow flycatchers can and do breed, in some locations, within Saltcedar habitat it can serve as vital habitat in the recovery of this species.
The San Pedro River Preserve
The San Pedro River Preserve is a Nature Conservancy preserve in Dudleyville, Arizona.
The Preserve comprises of deeded land along the San Pedro River acquired for the protection of southwestern willow flycatcher
The willow flycatcher ('' ...
was purchased by the Nature Conservancy
The Nature Conservancy (TNC) is a global environmental organization headquartered in Arlington, Virginia. it works via affiliates or branches in 79 countries and territories, as well as across every state in the US.
Founded in 1951, The Natu ...
to preserve habitat for this subspecies. North American beaver
The North American beaver (''Castor canadensis'') is one of two Extant taxon, extant beaver species, along with the Eurasian beaver (''Castor fiber''). It is native to North America and introduced in South America (Patagonia) and Europe (primari ...
s (''Castor canadensis'') are thought to play a critical role in widening riparian width, openings in dense vegetation, and retention of surface water through the willow flycatcher breeding season. This subspecies was described by A.R. Phillips in 1948.
''E. t. traillii''
The eastern nominate
Nomination is part of the process of selecting a candidate for either election to a public office, or the bestowing of an honor or award. A collection of nominees narrowed from the full list of candidates is a short list.
Political office
In the ...
subspecies of the willow flycatcher (''E. t. traillii'') was described by Audubon
The National Audubon Society (Audubon; ) is an American non-profit environmental organization dedicated to conservation of birds and their habitats. Located in the United States and incorporated in 1905, Audubon is one of the oldest of such org ...
in 1828. It breeds from the eastern coast of the United States to the western Rocky Mountains
The Rocky Mountains, also known as the Rockies, are a major mountain range and the largest mountain system in North America. The Rocky Mountains stretch in straight-line distance from the northernmost part of western Canada, to New Mexico in ...
.[
]
References
External links
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{{Taxonbar, from=Q903847
willow flycatcher
The willow flycatcher (''Empidonax traillii'') is a small insect-eating, neotropical migrant bird of the tyrant flycatcher family. There are four subspecies of the willow flycatcher currently recognized, all of which breed in North America (inc ...
Birds of North America
Native birds of Western Canada
Native birds of Eastern Canada
Birds of the United States
willow flycatcher
The willow flycatcher (''Empidonax traillii'') is a small insect-eating, neotropical migrant bird of the tyrant flycatcher family. There are four subspecies of the willow flycatcher currently recognized, all of which breed in North America (inc ...
Willow flycatcher
The willow flycatcher (''Empidonax traillii'') is a small insect-eating, neotropical migrant bird of the tyrant flycatcher family. There are four subspecies of the willow flycatcher currently recognized, all of which breed in North America (inc ...