dcsimg

Lifespan, longevity, and ageing

provided by AnAge articles
Maximum longevity: 11 years (wild) Observations: One individual was at least 11 years of age when recaptured (http://bna.birds.cornell.edu/).
license
cc-by-3.0
copyright
Joao Pedro de Magalhaes
editor
de Magalhaes, J. P.
partner site
AnAge articles

Comprehensive Description

provided by Smithsonian Contributions to Zoology
Empidonax traillii (Audubon)

The division of the “Traill's flycatcher complex” into 2 species, the willow flycatcher, E. traillii, and the alder flycatcher, E. alnorum, necessitates a review of the records of cowbird parasitism of the former composite. So far as may be judged from the data available (the original data slips, from which the early (Friedmann, 1929) compilation was made, are no longer available), most of the eastern records appear to deal with the willow flycatcher. The alder flycatcher, now restricted to the boreal forest region, may be largely allopatric with the brown-headed cowbird.

The following comments, therefore, refer to the willow flycatcher portion of this complex. In their detailed study of the flycatchers of Illinois, Graber, Graber, and Kirk (1974:42) write that “Traill's flycatcher must be very uncommonly parasitized by cowbirds in Illinois, as we know of but 1 other record (Poling 1889) than the 1 reported by Friedmann (1963).” (The latter was a case found near Chicago in 1947.) The absence of Illinois records is certainly puzzling, particularly when we consider the number of cases reported from nearby areas in Michigan and Ohio. We have noted numerous records subsequent to the 1963 compilation (Friedmann, pp. 54–55) from many areas, but none from Illinois. Yet there is no dearth of nest records year after year in Illinois for this flycatcher, and there is no scarcity of cowbirds there.

The Western Foundation's collections contain 237 sets of eggs of this species, 20 of which (8.4 percent) are parasitized. Breaking this down by subspecies, there are 57 sets of nominate E. traillii, 7 of which (13.7 percent) have cowbird eggs, and 186 sets of E. traillii brewsteri, 13 of which (6.9 percent) are parasitized. This difference seems to be borne out generally: the western populations of E. traillii (E. t. brewsteri) experience only about half as much parasitism as do the eastern ones (E. traillii, possibly plus E. alnorum). The Cornell University nest records files have entries on 130 nests of the Traill's flycatcher (not broken down by races). Only 6 (4.6 percent) of these were parasitized. In Nebraska, Holcomb (1972:55) studied 88 nests of this flycatcher; 7 of these (8.0 percent) were parasitized, but in none of them were any cowbird fledglings produced. The Ontario nest record files have data on 159 nests of the entire Traill's flycatcher complex. Of these, 27 (17.0 percent) were parasitized. Of these 27 cases, 5 are definitely known to refer to E. traillii and 1 to E. alnorum.

LEAST FLYCATCHER

Empidonax minimus (Baird and Baird)

To the relatively few (19 in Friedmann, 1963:55) earlier records of this flycatcher as a victim of the brown-headed cowbird, we may now add 20 additional instances, an increase of over 100 percent. In 1970, the least flycatcher was noted for the first time in southern Vancouver Island, near Victoria, and was found to be parasitized. This record involves the parasite race M. ater artemisiae, as does also a parasitized set of eggs from Alberta, now in the collection of the Delaware Museum of Natural History. Also pertaining to M. ater artemisiae are 5 records of parasitized nests of the least flycatcher in Manitoba, 1960–1971, in the files of the Prairie Nest Records Scheme at the Manitoba Museum of Man and Nature.

Two additional records for the eastern race of the cowbird, M. ater ater, are: 1 from Marlboro, Massachusetts, 2 June 1912, in the collections of the Western Foundation; and 1 from Ontario in the Ontario nest card files at the Royal Ontario Museum of Zoology. Bull (1974:537) lists 7 instances of parasitism on the least flycatcher in New York State; 6 of these are additions to the 1963 compilation. The Ontario nest records files at Toronto have data on 151 nests of the least flycatcher and 3 of these (2.0 percent) were parasitized.

HAMMOND'S FLYCATCHER
license
cc-by-nc-sa-3.0
bibliographic citation
Friedmann, Herbert, Kiff, Lloyd F., and Rothstein, Stephen I. 1977. "A further contribution of knowledge of the host relations of the parasitic cowbirds." Smithsonian Contributions to Zoology. 1-75. https://doi.org/10.5479/si.00810282.235

Willow flycatcher

provided by wikipedia EN

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. There are four subspecies of the willow flycatcher currently recognized, all of which breed in North America (including three subspecies that breed in California).[2] Empidonax flycatchers are almost impossible to tell apart in the field so biologists use their songs to distinguish between them.[3] The binomial commemorates the Scottish zoologist Thomas Stewart Traill.

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 .[4]

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.[7]

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'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 have been found in their fecal samples.

Subspecies

The subspecies are best distinguished from each other by their songs.[8] In addition, the four subspecies have significant genetic differences based on mitochondrial DNA analysis.[9] Their winter ranges have been elucidated using mitochondrial DNA genetic studies of 172 birds sampled in winter combined with plumage coloration and morphological differences.[2]

The four subspecies of the willow flycatcher are:[7][10]

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[11] north along the western side of the Sierra Nevada, and in Oregon and Washington west of the Cascade range.[12]

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.[12] 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.[7] 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.

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.[12]

Saltcedar (Tamarix ramosissima) 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.[13] 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.[14] 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.[15]

The San Pedro River Preserve was purchased by the Nature Conservancy to preserve habitat for this subspecies. 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.[16] This subspecies was described by A.R. Phillips in 1948.

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.[7]

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. ^ a b 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. ^ Godfrey, W. Earl (1966). The Birds of Canada. Ottawa: National Museum of Canada. p. 255.
  6. ^ Sibley, David Allen (2000). The Sibley Guide to Birds. New York: Knopf. p. 326. ISBN 0-679-45122-6.
  7. ^ a b c d 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.
  8. ^ Sedgwick, James A. (2001). "Geographic Variation in the Song of Willow Flycatchers: Differentiation between Empidonax traillii adastus and E. t. extimus". The Auk. 118 (2): 366–379. doi:10.1642/0004-8038(2001)118[0366:GVITSO]2.0.CO;2. S2CID 86066851.
  9. ^ Paxton, E.H. (2000). Molecular genetic structuring and demographic history of the Willow Flycatcher (PDF) (M.Sc.). Flagstaff, Arizona: Northern Arizona University. Retrieved 17 February 2012.
  10. ^ Gill, F.; Donsker, D., eds. (2014). "IOC World Bird List (v 4.4)". doi:10.14344/IOC.ML.4.4. Retrieved 14 November 2014. {{cite journal}}: Cite journal requires |journal= (help)
  11. ^ (S. Laymon, pers. comm.)
  12. ^ a b c Craig, Diane; Williams, Pamela L. (1998). Willow Flycatcher (Empidonax traillii). The Riparian Bird Conservation Plan: a strategy for reversing the decline of riparian-associated birds in California. California Partners in Flight. (Report). PRBO Conservation Science. Retrieved 16 February 2013.
  13. ^ 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.
  14. ^ 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.
  15. ^ 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.
  16. ^ Finch, Deborah M.; Stoleson, Scott H. (2000). Status, ecology, and conservation of the Southwestern Willow Flycatcher. Gen. Tech. Rep. RMRS-GTR-60 (PDF) (Report). Ogden, Utah: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station. p. 131. Retrieved 17 February 2012.

license
cc-by-sa-3.0
copyright
Wikipedia authors and editors
original
visit source
partner site
wikipedia EN

Willow flycatcher: Brief Summary

provided by wikipedia EN
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. 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 commemorates the Scottish zoologist Thomas Stewart Traill.

license
cc-by-sa-3.0
copyright
Wikipedia authors and editors
original
visit source
partner site
wikipedia EN