Willow flycatcher

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Willow flycatcher
Southwestern Willow Flycatcher.jpg
E. t. extimus
Empidonax traillii call ⓘ
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Class: Aves
Order: Passeriformes
Family: Tyrannidae
Genus: Empidonax
Species:
E. traillii
Binomial name
Empidonax traillii
(Audubon, 1828)
Empidonax traillii map.svg
Approximate distribution map
  Breeding
  Migration
  Nonbreeding
Summer breeding and winter ranges of willow flycatcher subspecies from USGS southwestern willow flycatcher survey protocol Summer breeding and winter ranges of Willow Flycatcher subspecies from Sogge et al, USGS 2010.JPG
Summer breeding and winter ranges of willow flycatcher subspecies from USGS southwestern willow flycatcher survey protocol

The willow flycatcher (Empidonax traillii) is a small insect-eating, neotropical migrant bird of the tyrant flycatcher family native to North America.

Contents

Taxonomy

There are four subspecies currently recognized, all of which breed in North America (including three subspecies that breed in California). [2] At one time, this bird and the alder flycatcher (Empidonax alnorum) were considered to be a single species, Traill's flycatcher.Their song is the only reliable method to tell them apart in the field. [3] [4] The binomial commemorates the Scottish zoologist Thomas Stewart Traill.

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 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 to 800 m (2,640 ft) at the South Fork Kern River and 910 m (3,000 ft) at upper San Luis Rey River in California and to over 2,600 m (8,530 ft) in Arizona, southwestern Colorado, and north-central New Mexico. This subspecies was described by A.R. Phillips in 1948.

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, the Santa Margarita River and Pilgrim, De Luz, French, and Las Flores creeks; as well as on the Santa Ynez River. In 1996, breeding was confirmed along the Arizona side of the lower Colorado River at Lake Mead Delta and at Topock Marsh. Examination of museum specimens of 578 migrating and wintering E. t. extimus indicating that Guatemala to Costa Rica constitutes the main winter range.

This species is experiencing population declines throughout the Southwest due to habitat loss/alteration and invasive species of grass. One of these is saltcedar ( Tamarix ramosissima), found throughout the Southwest, where it has replaced essential vegetation by outcompeting native species in riparian areas where the southwestern willow flycatcher is found. [5] In two sites, one in Arizona and the other in New Mexico, native trees were able to replace patches of saltcedar 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. [6] However, it is important to note that because willow flycatchers can and do breed, in some locations, within saltcedar habitat, it can occasionally serve as vital habitat in the recovery of this species. [7]

The San Pedro River Preserve was purchased by the Nature Conservancy to preserve habitat for this subspecies. NatureServe considers the subspecies Imperiled. [8] North American beavers (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.

E. t. traillii

The eastern nominate subspecies of the willow flycatcher (E. t. traillii) was described by Audubon in 1828. It breeds from the eastern coast of the United States to the western Rocky Mountains.

Description

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.

Standard Measurements [9] [10]
length 130–150 mm (5.2–6 in)
weight 13.5 g (0.48 oz)
wingspan 220 mm (8.5 in)
wing 68.7–75.6 mm (2.70–2.98 in)
tail 54–64.5 mm (2.13–2.54 in)
culmen 10.5–12.3 mm (0.41–0.48 in)
tarsus 15.5–18.0 mm (0.61–0.71 in)

Distribution and habitat

Their breeding habitat is deciduous thickets, especially willows and often near water, across the United States and southern Canada. They make a cup nest in a vertical fork in a shrub or tree.

These neotropical birds migrate to Mexico and Central America, and in small numbers as far south as Ecuador in South America, often selecting winter habitat near water. Willow flycatchers travel approximately 1,500–8,000 km (930–4,970 mi) each way between wintering and breeding areas. [11]

This bird's song is a sneezed fitz-bew. The call is a dry whit.

Food resources

Willow flycatcher feed on insects; common hoverflies ( Syritta pipiens) have been found in their fecal samples. They wait on a perch near the top of a shrub and fly out to catch insects in flight, also sometimes picking insects from foliage while hovering. They may eat some berries. This bird competes for habitat with the alder flycatcher where their ranges overlap.

Related Research Articles

<span class="mw-page-title-main">Alder flycatcher</span> Species of bird

The alder flycatcher is a small insect-eating bird of the tyrant flycatcher family. The genus name Empidonax is from Ancient Greek empis, "gnat", and anax, "master". The specific alnorum is Latin and means "of the alders".

<span class="mw-page-title-main">Virgin River</span> Tributary of the Colorado River in the southwestern United States

The Virgin River is a tributary of the Colorado River in the U.S. states of Utah, Nevada, and Arizona. The river is about 162 miles (261 km) long. It was designated Utah's first wild and scenic river in 2009, during the centennial celebration of Zion National Park.

<span class="mw-page-title-main">Ecology of the Sierra Nevada</span> Ecological features of the Sierra Nevadas

The ecology of the Sierra Nevada, located in the U.S. states of California and Nevada, is diverse and complex. The combination of climate, topography, moisture, and soils influences the distribution of ecological communities across an elevation gradient from 500 to 14,500 feet. Biotic zones range from scrub and chaparral communities at lower elevations, to subalpine forests and alpine meadows at the higher elevations. Particular ecoregions that follow elevation contours are often described as a series of belts that follow the length of the Sierra Nevada. There are many hiking trails, paved and unpaved roads, and vast public lands in the Sierra Nevada for exploring the many different biomes and ecosystems.

The San Pedro River Preserve is a Nature Conservancy preserve in Dudleyville, Arizona.

<span class="mw-page-title-main">Hammond's flycatcher</span> Species of bird

Hammond's flycatcher is a flycatcher in the family Tyrannidae. This small insectivorous bird inhabits the coniferous and mixed forests of western North America. The name of this bird commemorates William Alexander Hammond who was the surgeon general of the US Army. Hammond collected bird specimens for Spencer Fullerton Baird.

<span class="mw-page-title-main">American gray flycatcher</span> Species of bird

The American gray flycatcher, or American grey flycatcher, or just gray flycatcher as it is known in North America, is a small, insectivorous passerine in the tyrant flycatcher family. It is common in the arid regions of western North America, especially the Great Basin. From sagebrush steppes to pinyon-juniper woodlands and ponderosa pine forests, this flycatcher forages for insects from shrubs or low tree branches.

<span class="mw-page-title-main">Buff-breasted flycatcher</span> Species of bird

The buff-breasted flycatcher is a small insectivorous bird. It is the smallest Empidonax flycatcher, typically ranging from 11.5 to 13 cm in size.

<span class="mw-page-title-main">Skinner Reservoir</span> Reservoir in Riverside County, California

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<span class="mw-page-title-main">San Pedro River (Arizona)</span> River in northern Sonora, Mexico, and southern Arizona, USA

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Tamarix ramosissima, commonly known as saltcedarsalt cedar, or tamarisk, is a deciduous arching shrub with reddish stems, feathery, pale green foliage, and characteristic small pink flowers.

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<i>Diorhabda elongata</i> Species of beetle

Diorhabda elongata is a species of leaf beetle known as the Mediterranean tamarisk beetle (MTB) which feeds on tamarisk trees from Portugal and Algeria east to southern Russia. The MTB is used in North America as a biological pest control agent against saltcedar or tamarisk, an invasive species in arid and semi-arid ecosystems.

<i>Diorhabda carinata</i> Species of beetle

Diorhabda carinata is a species of leaf beetle known as the larger tamarisk beetle which feeds on tamarisk trees from Ukraine, eastern Turkey and Syria east to northwest China, Kyrgyzstan and Pakistan, extending as far south as southern Iran. It is used in North America as a biological pest control agent against saltcedar or tamarisk, an invasive species in arid and semi-arid ecosystems.

<i>Diorhabda sublineata</i> Species of beetle

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<span class="mw-page-title-main">Imperial National Wildlife Refuge</span> Nature preserve in Arizona and California

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<span class="mw-page-title-main">Bill Williams River National Wildlife Refuge</span> Protected area in Arizona

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<span class="mw-page-title-main">Canebrake Ecological Reserve</span> Ecological reserve in the South Fork Valley of Kern County, California

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<span class="mw-page-title-main">Kern River Preserve</span>

The Audubon Kern River Preserve is a riparian nature reserve owned by the National Audubon Society in the US state of California, near Weldon in Kern County.

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<span class="mw-page-title-main">Western flycatcher</span>

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References

  1. ↑ BirdLife International (2016). "Empidonax traillii". IUCN Red List of Threatened Species . 2016: e.T22699848A93751510. doi: 10.2305/IUCN.UK.2016-3.RLTS.T22699848A93751510.en . Retrieved 12 November 2021.
  2. ↑ Paxton, Eben H.; Unitt, Philip; Sogge, Mark K.; Whitfield, Mary; Keim, Paul (2011). "Winter Distribution of Willow Flycatcher Subspecies". The Condor. 113 (3): 608–618. doi: 10.1525/cond.2011.090200 . S2CID   59414997.
  3. ↑ "Southwestern Willow Flycatcher (Empidonax traillii extimus)". U.S. Fish and Wildlife Service Nevada Office. Retrieved 16 February 2013.
  4. ↑ "Willow flycatcher". All About Birds. Cornell Lab of Ornithology . Retrieved 16 February 2013.
  5. ↑ DeLoach, CJ; Dudley, Tom (2004). "Saltcedar (Tamarix spp.), endangered species, and biological weed control - Can they Mix?". Weed Technology. 18: 1542–1551. doi:10.1614/0890-037X(2004)018[1542:STSESA]2.0.CO;2. S2CID   35498749.
  6. ↑ Bean, Daniel; Dudley, Tom (2012). "Tamarisk biocontrol, endangered species risk and resolution of conflict through riparian restoration". BioControl. 57 (2): 331. doi:10.1007/s10526-011-9436-9. S2CID   16497604.
  7. ↑ Sferra, Susan; Paxton, Eben; Sogge, Mark (2008). "Tamarix as Habitat for Birds: Implications for Riparian Restoration in the Southwestern United States". Restoration Ecology. 16: 146–154. doi:10.1111/j.1526-100X.2008.00357.x. S2CID   56042221.
  8. ↑ "Empidonax traillii extimus. NatureServe Explorer 2.0". explorer.natureserve.org. Retrieved 2023-06-23.
  9. ↑ Godfrey, W. Earl (1966). The Birds of Canada. Ottawa: National Museum of Canada. p. 255.
  10. ↑ Sibley, David Allen (2000). The Sibley Guide to Birds . New York: Knopf. p.  326. ISBN   0-679-45122-6.
  11. ↑ Sogge, Mark K.; Marshall, Robert M.; Sferra, Susan J.; Tibbitts, Timothy J. (May 1997). A Southwestern Willow Flycatcher Natural History Summary and Survey Protocol: Technical Report NPS/NAUCPRS/NRTR-97/12 (PDF) (Report). National Park Service and Northern Arizona University. p. 37. Retrieved 17 February 2012.


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