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Eurasian teal

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Eurasian teal
Wintering male from Mangaon, Maharashtra, India
Calls
Scientific classificationEdit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Anseriformes
Family: Anatidae
Genus: Anas
Species:
A. crecca
Binomial name
Anas crecca
Distribution map
light green: nesting area
blue: wintering area
dark green: resident all year
Synonyms

Anas crecca creccaLinnaeus,1758
Anas crecca nimiaFriedmann,1948

TheEurasian teal(Anas crecca),common teal,orEurasian green-winged tealis a common and widespreadduckthat breeds intemperateEurosiberiaandmigratessouth in winter.[2]The Eurasian teal is often called simply thetealdue to being the only one of these smalldabbling ducksin much of its range.[3]The bird gives its name to the blue-green colourteal.

It is a highly gregarious duck outside the breeding season and can form large flocks. It is commonly found in sheltered wetlands and feeds on seeds and aquatic invertebrates. TheNorth Americangreen-winged teal(A. carolinensis) was formerly (and sometimes is still) considered asubspeciesofA. crecca.

Taxonomy

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The Eurasian teal belongs to the "true" teals, a group of smallAnasdabbling ducks closely related to themallard(A. platyrhynchos) and its relatives; that latter group in fact seems to haveevolvedfrom a true teal. It forms asuperspecieswith thegreen-winged tealand thespeckled teal(A. flavirostris). A proposedsubspecies,A. c. nimiaof theAleutian Islands,differs only in slightly larger size; it is probably not distinct.[3][4][5]

Whether the Eurasian and green-winged teals are to be treated as one or two species is still being reviewed by theAmerican Ornithologists' Union,[6]while theInternational Union for Conservation of NatureandBirdLife Internationalseparate them nowadays.[1]Despite the almost identical and highlyapomorphicnuptial plumageof their males, which continues to puzzle scientists, they seem well distinct species, as indicated by a wealth of behavioural, morphological, and molecular data.[4][5][7][8]

The Eurasian teal was first scientifically named byCarl Linnaeusin his 1758 edition ofSystema naturae.HisLatindescription reads:[Anas] macula alarum viridi, linea alba supra infraque oculos– "a duck with green speculum, a white line above and below the eyes" – and his primary reference was the bird's description in his earlier workFauna Svecica.[9]In fact, the description he used inSystema Naturaewas the name under which the bird went in theFauna Svecica,demonstrating the value of his newbinomial nomenclatureby compressing the long-winded names formerly used inbiological classificationinto much simplerscientific nameslikeAnas crecca.Linnaeus also noted in his description that earlier authors had already written about the Eurasan teal at length:Conrad Gessner[10]had described it in theHistoriae animaliumas theanas parva( "small duck" ) among hisquerquedulae( "teals" );Ulisse Aldrovandi[11]had called itphascadeorquerquedula minor( "lesser teal" ), and was duly referenced byFrancis Willughby[12]who named the speciesquerquedula secunda Aldrovandi( "the second teal of Aldrovandi"[note 1]).John Ray[14]may be credited with formally introducing the name "common teal", whileEleazar Albin[15]called it simply "the teal". As regards thetype localityLinnaeus simply remarked that it inhabitsfreshwaterecosystems inEurope.[13]

The scientific name is fromLatinAnas,"duck" andkricka,the Swedish name for this species.[16]Thespecific nameof Linnaeus isonomatopoetic,referring to the male's characteristic call which was already discussed by Linnaeus' sources.[citation needed]The scientific name of the Eurasian teal—unchanged since Linnaeus' time— therefore translates as "duck that makescryc";common names like theBokmålkrikkand,DanishkrikandandGermanKrickentemean the same.

  • A. crecca drake in nuptial plumage, showing horizontal white stripe from shoulder
    A. creccadrake in nuptial plumage, showing horizontal white stripe from shoulder
  • A. carolinensis (A. crecca carolinensis) drake in nuptial plumage, showing vertical white stripe from shoulder
    A. carolinensis(A. crecca carolinensis) drake in nuptial plumage, showing vertical white stripe from shoulder

Description

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Male (top) innuptial plumageand female. Male has the wide white wing stripe and conspicuous face markings, which gave the colourtealits name.

The Eurasian teal is one of the smallest extantdabbling ducksat 34–43 cm (13–17 in) length and with an average weight of 360 g (13 oz) in drake (males) and 340 g (12 oz) in hens (females). The wings are 17.5–20.4 cm (6.9–8.0 in) long, yielding a wingspan of 53–59 cm (21–23 in). The bill measures 3.2–4 cm (1.3–1.6 in) in length, and thetarsus2.8–3.4 cm (1.1–1.3 in).[3][17]

From a distance, the drakes innuptial plumageappear grey, with a dark head, a yellowish behind, and a white stripe running along the flanks. Their head and upper neck ischestnut,with a wide and iridescent dark green patch of half-moon- or teardrop-shape that starts immediately before the eye and arcs to the upper hindneck. The patch is bordered with thin yellowish-white lines, and a single line of that colour extends from the patch's forward end, curving along the base of the bill. The breast isbuffwith small round brown spots. The center of the belly is white, and the rest of the body plumage is mostly white with thin and dense blackishvermiculations,appearing medium grey even at a short distance. The outer scapular feathers are white, with a black border to the outer vanes, and form the white side-stripe when the bird is in resting position. The primaryremigesare dark greyish brown; thespeculum feathersare iridescent blackish-green with white tips, and form the speculum together with the yellowish-white tips of the larger upperwing coverts (which are otherwise grey). The underwing is whitish, with grey remiges, dense dark spotting on the inner coverts and a dark leading edge. The tail and tail coverts are black, with a bright yellowish-buff triangular patch in the center of the coverts at each side.[17]

In non-breeding (eclipse) plumage, the drake looks more like the hen; it is more uniform in colour, with a dark head and vestigial facial markings. The hen itself is yellowish-brown, somewhat darker on wings and back. It has a dark greyish-brown upper head, hindneck, eyestripe and feather pattern. The pattern is dense short streaks on the head and neck, and scaly spots on the rest of the body; overall they look much like a tinymallard(A. platyrhynchos) hen when at rest. The wings are coloured similar to the drake's, but with brown instead of grey upperwing coverts that have less wide tips, and wider tips of the speculum feathers. The hen'srectriceshave yellowish-white tips; the midbelly is whitish with some dark streaking.[17]

Immatures are coloured much like hens, but have a stronger pattern. Thedownyyoung are coloured like in other dabbling ducks: brown above and yellow below, with a yellowsupercilium.They are recognizable by their tiny size however, weighing just 15 g (0.53 oz) at hatching.[3][17][18]

The drake's bill is dark grey, in eclipse plumage often with some light greenish or brownish hue at the base. The bill of hens and immatures is pinkish or yellowish at the base, becoming dark grey towards the tip; the grey expands basewards as the birds age. The feet are dark grey in males and greyisholiveor greyish-brown in females and immatures. Theirisis always brown.[17]

Moults during summer. Male in eclipse resembles female, but with darker upperparts and grey bill. Flight feathers are moulted simultaneously and birds are flightless for up to 4 weeks.[19]

This is a noisy species. The male whistlescrycorcreelycc,not loud but very clear and far-carrying. The female has a feeblekehorneehquack.[17]

Males in nuptial plumage are distinguished fromgreen-winged tealsby the horizontal white scapular stripe, the lack of averticalwhite bar at the breast sides, and the quite conspicuous light outlines of the face patch, which are indistinct in the green-winged teal drake. Males in eclipse plumage, females and immatures are best recognised by their small size, calls, and the speculum; they are hard to tell apart from the green-winged teal however.[17]

Distribution and habitat

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Wintering birds atPurbasthali,BurdwanDistrict ofWest Bengal(India)

The Eurasian teal breeds across thePalearcticand mostly winters well south of its breeding range. However, in the milder climate oftemperateEurope,the summer and winter ranges overlap. For example, in theUnited KingdomandIrelanda small summer population breeds, but far greater numbers ofSiberianbirds arrive in winter. In theCaucasusregion, westernAsia Minor,along the northern shores of theBlack Sea,and even on the south coast ofIcelandand on theVestmannaeyjar,the species can be encountered all year, too.[17]

In winter, there are high densities around theMediterranean,including the entireIberian Peninsulaand extending west toMauretania;onJapanandTaiwan;as well as inSouth Asia.Other important wintering locations include almost the entire length of theNile Valley,theNear EastandPersian Gulfregion, the mountain ranges of northernIran,andSouth Koreaand continentalEastandSoutheast Asia.More isolated wintering grounds areLake Victoria,theSenegal Riverestuary, the swamps of the upperCongo River,theinlandandsea deltasof theNiger River,and the centralIndus Rivervalley. Vagrants have been seen in inlandZaire,Malaysia,onGreenland,and on theMarianas,PalauandYapinMicronesia;[20]they are regularly recorded on theNorth Americancoasts south toCaliforniaandSouth Carolina,[17]including annual sightings on the island ofNewfoundland.[21]

From tracking wintering teal in Italy, most individuals departed the wintering grounds between mid-February and March, using the Black-Sea-Mediterranean flyway to reach their breeding grounds, from central Europe to east of the Urals, by May. This slow migration is due to long stopovers near the start of migration, mainly in south-eastern Europe.[22]

Altogether, the Eurasian teal is much less common than its American counterpart, though still very plentiful. Its numbers are mainly assessed by counts of wintering birds; some 750,000 are recorded annually around theMediterraneanandBlack Seas,250,000 intemperatewesternEurope,and more than 110,000 inJapan.In 1990 and 1991, a more detailed census was undertaken, yielding over 210,000 birds wintering inIran,some 109,000 inPakistan,about 77,000 inAzerbaijan,some 37,000 inIndia,28,000 inIsrael,over 14,000 inTurkmenistanand almost 12,000 inTaiwan.It appears to be holding its own currently, with its slow decline of maybe 1–2% annually in the 1990s – presumably mainly due to drainage andpollutionof wetlands – not warranting action other than continuing to monitor the population and possibly providing better protection forhabitaton the wintering grounds. TheIUCNandBirdLife Internationalclassify the Eurasian teal as a species ofLeast Concern,unchanged from their assessment before the split of the more numerousA. carolinensis.[1][3][17]

The Eurasian teal is one of the species to which theAgreement on the Conservation of African-Eurasian Migratory Waterbirds(AEWA) applies.

Behaviour

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Eggs

Thisdabbling duckis highly gregarious outside of the breeding season and will form large flocks. In flight, the fast, twisting flocks resemblewaders;despite its short legs, it is also rather nimble on the ground by ducks' standards. In the breeding season, it is a common inhabitant of shelteredfreshwaterwetlandswith some tall vegetation, such astaigabogs or smalllakesandpondswith extensivereedbeds.In winter, it is often seen inbrackishwaters and even in shelteredinletsandlagoonsalong the seashore.[17]

The Eurasian teal usually feeds by dabbling, upending or grazing; it may submerge its head and on occasion even dive to reach food. In the breeding season it eats mainlyaquaticinvertebrates,such ascrustaceans,insectsand theirlarvae,molluscsandworms.In winter, it shifts to a largelygranivorousdiet, feeding onseedsof aquaticplantsandgrasses,includingsedgesandgrains.Diurnalthroughout the breeding season, in winter they are oftencrepuscularor evennocturnalfeeders.[17]

It nests on the ground, near water and under cover. The pairs form in the winter quarters and arrive on the breeding grounds together, starting about March. The breeding starts some weeks thereafter, not until May in the most northernly locations. The nest is a deep hollow lined with dry leaves anddown feathers,built in dense vegetation near water. After the females have started laying, the males leave them and move away for shorter or longer distances, assembling in flocks on particular lakes where theymoultintoeclipse plumage;they will usually encounter their offspring only in winter quarters. Theclutchmay consist of 5–16 eggs, but usually numbers 8–11; they are incubated for 21–23 days. The young leave the nest soon after hatching and are attended by the mother for about 25–30 days, after which theyfledge.The drakes and the hens with young generally move to the winter quarters separately. After the first winter, the young moult into adult plumage. The maximum recorded lifespan – though it is not clear whether this refers to the common or the green-winged teal—was over 27 years, which is rather high for such a small bird.[17]

Notes

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  1. ^Aldrovandi's "first teal" was theGarganey,which was consequently scientifically described asAnas querquedula( "teal-duck" ).[13]

References

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  1. ^abcBirdLife International (2020)."Anas crecca".IUCN Red List of Threatened Species.2020:e.T22680321A181692388.doi:10.2305/IUCN.UK.2020-3.RLTS.T22680321A181692388.en.Retrieved19 November2021.
  2. ^Arzel, C.; Elmberg, J.; Guillemain, M. (January 2007)."A flyway perspective of foraging activity in Eurasian Green-winged Teal".Canadian Journal of Zoology.85(1): 81–91.doi:10.1139/z06-201.
  3. ^abcdeCarboneras, Carles (1992). del Hoyo, Josep; Elliott, Andrew; Sargatal, Jordi (eds.).Family Anatidae (Ducks, Geese and Swans).Handbook of Birds of the World.Vol. 1: Ostrich to Ducks. Barcelona: Lynx Edicions. pp.536–629, plates 40–50.ISBN84-87334-10-5.
  4. ^abLivezey, Bradley C. (1991)."A phylogenetic analysis and classification of recent dabbling ducks (Tribe Anatini) based on comparative morphology"(PDF).Auk.108(3): 471–507.doi:10.2307/4088089.JSTOR4088089.
  5. ^abJohnson, Kevin P.; Sorenson, Michael D. (1999)."Phylogeny and biogeography of dabbling ducks (genus Anas): a comparison of molecular and morphological evidence"(PDF).Auk.116(3): 792–805.doi:10.2307/4089339.JSTOR4089339.
  6. ^South American Classification Committee(2008)."Part 1. Struthioniformes to Cathartiformes, Version of 22 December 2008".A classification of the bird species of South America.Retrieved5 January2009.
  7. ^Laurie-Ahlberg, C.C.; McKinney, F. (1979). "The nod-swim display of male Green-winged Teal (Anas crecca) ".Animal Behaviour.27:165–172.doi:10.1016/0003-3472(79)90136-2.S2CID53155090.
  8. ^Sangster, George; Knox, Alan G.; Helbig, Andreas J.; Parkin, David T. (2002). "Taxonomic recommendations for European birds".Ibis.144:153–159.doi:10.1046/j.0019-1019.2001.00026.x.
  9. ^Linnaeus, Carl(1746): 109.Anas macula alarum viridi: linea alba supra infraque oculos.In: Fauna Svecica Sistens Animalia Sveciæ Regni, etc.(1st ed.): 39–40 [in Latin]. Conrad & Georg Jacob Wishoff, Leiden ( "Lugdunum Batavorum" ).
  10. ^Gessner, Conrad(1555).Historiae animalium(in Latin). Vol. 3. Zürich [Tigurium]: Christoph Froschauer. pp. 103–105. Archived fromthe originalon 2012-12-05.Retrieved2009-01-06.
  11. ^Aldrovandi, Ulisse (Ulyssis Aldrovandus)(1637).Ornithologia(in Latin). Vol. 3:Tomus tertius ac postremus(2nd ed.). Bologna [Bononia]: Nicolò Tebaldini. pp. 207–209. Archived fromthe originalon 2012-12-11.Retrieved2009-01-06.
  12. ^Willughby, Francis(1676).Ornithologiae libri tres(in Latin). London: John Martyn. p. 290. Archived fromthe originalon 2012-12-09.
  13. ^abLinnaeus, Carl (1758).Systema naturae per regna tria naturae, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I. Editio decima, reformata.pp. 126–127.
  14. ^Ray, John (Joannis Raii)(1713).Synopsis methodica avium & piscium: opus posthumum, etc(in Latin). Vol. 1. London: William Innys. pp. 147–148. Archived fromthe originalon 2011-07-16.Retrieved2009-01-06.
  15. ^Albin, Eleazar(1731–1738):A natural history of the birds(3 volumes). William Innys, London.Vol.1, p.95, plate 100; vol. 2, p.91, plate 102
  16. ^Jobling, James A (2010).The Helm Dictionary of Scientific Bird Names.London: Christopher Helm. pp.46,121.ISBN978-1-4081-2501-4.
  17. ^abcdefghijklmMadge, S.; Burn, H. (1987).Wildfowl, an Identification Guide to the Ducks, Geese and Swans of the World.London: Christopher Helm.ISBN0713636475.
  18. ^"Anas crecca life history data".AnAge.2009.Retrieved6 January2009.
  19. ^RSPB Handbook of British Birds (2104). UKISBN978-1-4729-0647-2.
  20. ^Wiles, Gary J.; Johnson, Nathan C.; de Cruz, Justine B.; Dutson, Guy; Camacho, Vicente A.; Kepler, Angela Kay; Vice, Daniel S.; Garrett, Kimball L.; Kessler, Curt C.; Pratt, H. Douglas (2004)."New and Noteworthy Bird Records for Micronesia, 1986–2003".Micronesica.37(1): 69–96.
  21. ^eBird(2023)."Green-winged Teal".eBird Status and Trends, Data Version: 2022; Released: 2023.Retrieved7 March2024.
  22. ^Giunchi, D.; Baldaccini, N.E.; Lenzoni, A.; Luschi, P.; Sorrenti, M.; Cerritelli, G.; Vanni, L. (2019)."Spring migratory routes and stopover duration of satellite-tracked Eurasian TealsAnas creccawintering in Italy ".Ibis.161(2): 117–130.doi:10.1111/ibi.12602.hdl:11568/920031.
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