Willow flycatcher
Willow flycatcher | |
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E. t. extimus ⓘ | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Aves |
Order: | Passeriformes |
Family: | Tyrannidae |
Genus: | Empidonax |
Species: | E. traillii
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Binomial name | |
Empidonax traillii (Audubon, 1828)
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Approximate distribution map
Breeding
Migration
Nonbreeding
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The willow flycatcher (Empidonax traillii) is a small insect-eating,
.Taxonomy
There are four subspecies currently recognized, all of which breed in North America (including three subspecies that breed in California).
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
This species is experiencing population declines throughout the Southwest due to
The
E. t. traillii
The eastern
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] | |
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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
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.
References
- . Retrieved 12 November 2021.
- S2CID 59414997.
- ^ "Southwestern Willow Flycatcher (Empidonax traillii extimus)". U.S. Fish and Wildlife Service Nevada Office. Retrieved 16 February 2013.
- ^ "Willow flycatcher". All About Birds. Cornell Lab of Ornithology. Retrieved 16 February 2013.
- S2CID 35498749.
- S2CID 16497604.
- S2CID 56042221.
- ^ "Empidonax traillii extimus. NatureServe Explorer 2.0". explorer.natureserve.org. Retrieved 2023-06-23.
- ^ Godfrey, W. Earl (1966). The Birds of Canada. Ottawa: National Museum of Canada. p. 255.
- ISBN 0-679-45122-6.
- ^ 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.
External links
- "Southwestern Willow Flycatcher Site". Colorado Plateau Research Station. USGS.
- BirdLife species factsheet for Empidonax traillii
- "Empidonax traillii". Avibase.
- "Willow flycatcher media". Internet Bird Collection.
- Willow flycatcher photo gallery at VIREO (Drexel University)
- Interactive range map of Empidonax traillii at IUCN Red List maps
- Audio recordings of Willow flycatcher on Xeno-canto.