Eastern yellow wagtail explained

The eastern yellow wagtail (Motacilla tschutschensis) is a small passerine in the wagtail family Motacillidae, which also includes the pipits and longclaws. It was often classified as a subspecies of the Western yellow wagtail. It breeds in the eastern Palearctic and Alaska and migrates to South Asia and Australia.

Taxonomy

The eastern yellow wagtail was formally described in 1789 by the German naturalist Johann Friedrich Gmelin in his revised and expanded edition of Carl Linnaeus's Systema Naturae. He placed it with the wagtails in the genus Motacilla and coined the binomial name Motacilla tschutschensis.^{[1] [2]} The specific epithet tschutschensis is from the locality, the Chukchi Peninsula is eastern Russia.^[3] Gmelin based his account on the "Tchutschi wagtail" that had been described by John Latham in 1783 and by Thomas Pennant in 1785.^{[4] [5]} In his description Pennant wrote "Taken off the Tchutschi coat, with the Streights of Bering, Lat. 66, north." This is almost certainly the bird captured in 1778 during James Cook's third voyage to the Pacific Ocean. The naturalist William Wade Ellis, who accompanied Cook, produced a painting of the specimen and in the caption wrote "caught on board, lat. 66". Ellis's painting is now in the collection of the Natural History Museum, London.^{[6] [7]}

Four subspecies are recognised:^[8]

• M. t. plexa (Thayer & Bangs, 1914) – central north Siberia
• M. t. tschutschensis Gmelin, JF, 1789 – south Siberia, north Mongolia, east Kazakhstan and northwest China to northeast Siberia and northwest North America
• M. t. macronyx (Stresemann, 1920) – central south Siberia, northeast Mongolia and northeast China
• M. t. taivana (Swinhoe, 1863) – southeast Siberia to Sakhalin (east Russia), and far north Hokkaido (north Japan)

Three species of yellow wagtails are recognised in the Palearctic: the eastern yellow wagtail, the western yellow wagtail (Motacilla flava) and the citrine wagtail (Motacilla citreola). Phylogenetic analysis using mitochondrial DNA sequences produces a topology that conflicts with that obtained from when nuclear sequences are used. The topology from nuclear data more closely corresponds to the traditional phenotypic taxonomy.^{[9] [10]} The nuclear genetic divergence between the western and eastern yellow wagtails is small and some ornithologists choose to not split the species so that the eastern races become subspecies of M. flava.^[11]

Description

It is a slender 15–16 cm long bird, with the characteristic long, constantly wagging tail of its genus. The breeding adult male is basically olive above and yellow below. In other plumages, the yellow may be diluted by white. The heads of breeding males come in a variety of colours and patterns depending on subspecies.

The call is a characteristic high-pitched jeet.

Distribution and habitat

This species breeds in the East Palearctic and has a foothold in North America in Alaska. Populations migrate to south Asia and Australia. Vagrant individuals occur around the winter quarters at migration time. For example, on Palau in Micronesia migrant flocks of this species  - apparently of the Bering Sea yellow wagtail, and including many adult males  - are regularly seen, while further north on the Marianas, only the occasional stray individual  - usually females or immatures as it seems  - is encountered.^{[12] [13]}

Behaviour

This insectivorous bird inhabits open country near water, such as wet meadows. It nests in tussocks, laying 4–8 speckled eggs.

The Acanthocephalan parasite Apororhynchus paulonucleatus was discovered in the colon and cloaca of the eastern yellow wagtail.^[14]

Further reading

• Fraker MA & Fraker RN. (1980). Yellow Wagtail Motacilla-Flava East of the Mackenzie Delta Canada. Canadian Field-Naturalist. vol 94, no 4. p. 465-466.
• Hunt J & Standring I. (1995). A yellow wagtail Motacilla flava at Lake Mclarty. Western Australian Naturalist. vol 20, no 2. p. 61-64.
• Johnstone RE. (1982). The Yellow Wagtail Motacilla-Flava in Australia. Western Australian Naturalist. vol 15, no 3. p. 61-66.
• Moffatt JD. (1981). Yellow Wagtail Motacilla-Flava on Heron Island Queensland Australia with Notes on the Status of Southern Individuals. Emu. vol 81, no 1. p. 47-48.

Notes and References

1. Book: Gmelin, Johann Friedrich . Johann Friedrich Gmelin. 1789 . Systema naturae per regna tria naturae : secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis . 13th . 1, Part 2 . Latin . Lipsiae [Leipzig] . Georg. Emanuel. Beer . 962 .
2. Book: Mayr . Ernst . Ernst Mayr . Greenway . James C. Jr . 1960 . Check-List of Birds of the World . 9 . Museum of Comparative Zoology . Cambridge, Massachusetts . 134 .
3. Book: Jobling, James A. . 2010. The Helm Dictionary of Scientific Bird Names . Christopher Helm . London . 978-1-4081-2501-4 . 392 .
4. Book: Latham, John . John Latham (ornithologist) . 1783 . A General Synopsis of Birds . 2, Part 2 . Printed for Leigh and Sotheby . London . 403 .
5. Book: Pennant, Thomas . Thomas Pennant . 1785 . Arctic Zoology . 2 . Printed by Henry Hughs . London . 397 .
6. Stresemann . Erwin . Erwin Stresemann . 1949 . Birds collected in the north Pacific area during Capt. James Cook's last voyage (1778 and 1779) . Ibis . 91 . 2 . 244–255 [251] . 10.1111/j.1474-919X.1949.tb02264.x .
7. Lysaght . Averil . 1959 . Some eighteenth century bird paintings in the library of Sir Joseph Banks (1743-1820) . Bulletin of the British Museum (Natural History), Historical Series . 1 . 6 . 251-371 [338, No. 91] . 10.5962/p.92313 .
8. Web site: Gill . Frank . Frank Gill (ornithologist) . Donsker . David . Rasmussen . Pamela . Pamela Rasmussen . July 2023 . Waxbills, parrotfinches, munias, whydahs, Olive Warbler, accentors, pipits . IOC World Bird List Version 13.2 . International Ornithologists' Union . 21 August 2023 .
9. Drovetski . S.V. . Reeves . A.B. . Red'kin . Y.A. . Fadeev . I.V. . Koblik . E.A. . Sotnikov . V.N. . Voelker . G. . 2018 . Multi-locus reassessment of a striking discord between mtDNA gene trees and taxonomy across two congeneric species complexes . Molecular Phylogenetics and Evolution . 120 . 43–52 . 10.1016/j.ympev.2017.11.023. free . 29224786 .
10. Harris . R.B. . Alström . P. . Ödeen . A. . Leaché . A.D. . 2018 . Discordance between genomic divergence and phenotypic variation in a rapidly evolving avian genus (Motacilla) . Molecular Phylogenetics and Evolution . 120 . 183–195 . 10.1016/j.ympev.2017.11.020. 29246816 . 1707.03864 .
11. Hellquist . A. . Friberg . F. . Haldén . P. . Schmidt . P. . Ma . M. . Jun . G. . Olsson . U. . Alström . P. . 2021 . Taxonomic status of grey-headed Yellow Wagtails breeding in western China . Avian Research . 12 . 1 . 53 . 10.1186/s40657-021-00289-y . free .
12. Wiles . G. . Worthington . D. . Beck . R. . Pratt . D. . Aguon . C. . Pyle . R. . 2000 . Noteworthy bird records for Micronesia, with a summary of raptor sightings in the Mariana Islands, 1988-1999 . Micronesica . 32 . 257–284 .
13. Vanderwerf . E. . Wiles . G. . Marshall . A. . Knecht . M. . 2006 . Observations of migrants and other birds in Palau, April-May 2005, including the first Micronesian record of a Richard's Pipit . Micronesica . 39 . 11–29 .
14. Khokhlova . I. G. . Cimbaluk . A. K. . 1971 . Acanthocephala of the genus Apororhynchus Shipley, 1899 and a description of A. paulonucleatus n.sp. . KOLOS . 426–431.