Figure1. Currentand historical taxonomic breakdown of Artthusrubescerts A.0.U. 1957 WaterPipit (Artthus spinoletta) A.0.U. 1983 WaterPipit RockPipit Buff-•e•liedPipit(B.0.U.) (A. spinoletta) (A petrosin) or AmericanPipit (A.0.U.) ! i (A r.•ens) A s. splnoletta A. p. pe•rosus Subspecies A. s. coutelll A. p. littoralis A. s. blakistoni "AmericanPipits" "SiberianPipit" A. r. rubescerts •r. japonicus A. r. alticola Figure2. Field-basedsketch of a SiberianPipit seen on 29 October2001 in Ventura, California. Illustration by Andrew Birch. Figure3. Field-basedsketches of a Siberian(left) and American (A. r. pacificus)Pipit (right) seen on 23 November 2001 nearPerds, California. Illustration by Cin-TyLee. 388 NORTH AMERICAN BIRDS Noteson the distribution,vagrancy, and field identification of American Pipit and "SiberianPipit" Cin-TyLee eachother dosely. For thisreason, we referto A. r.japonicus as "Siberian Departmentof EarlhScience, MS-126 Pipit" in this paperand to the threeNorth Americansubspecies collec- RiceUniversity tively as "AmericanPipit" (Fig. 1; see illustrationsof basic-plumaged R O. Box 1892 birdson frontcover of thejournal). Webelieve that thischoice of com- Houston,Texas 77251 mon terminologywill reduceconfusion if Siberianand American Pipits (email:ctlee•rice.edu) areaccorded status as separate species in the future. When we consider both formstogether, we hereemploy the namepreferred for all four in Andrew Birch the Palearctic the"Buff-belliedPipit complex. • 1037South Ogden Drive SiberianPipit is a vagrantto Europe,the Middle East,and alongthe LosAngeles, California 90019 Pacificcoast of North America,whereas American Pipits vagrate to west- (emaJl:[email protected]) ern Europe(rubescerts) and are possiblyrare winterersin easternAsia (pacificus).In greaterdetail, however, the vagrancypatterns of Siberian Introduction and AmericanPipits are poorlyknown, as there is a gapin the literature The pipit Anthusrubescens-•called American Pipit by the American regardingthe subspecificidentification of themembers of the Buff-bellied Ornithologists'Union (A. O. U. 1998),Buff-bellied Pipit by the British Pipitcomplex. To our knowledge,the onlyrecent sources to addressthe Ornithologists'Union (B. O. U. 1986)•is currentlydivided into four complexare Parkes(1982) and Phillips(1991). However,both sources subspecies:japonicus, pacificus, ahicola, and rubescerts (A.O.U. 1957). The focusprimarily on identificationof thethree American subspedes in alter- first subspecies,japonicus, may be a candidatefor full-speciesstatus nateplumage. Alstr6mand Mild (1996), Lewingtonet al. (1991), and accordingto theAmerican Ornithologists' Union (A.O.U. 1989)because Beamanand Madge(1998) discussthe identificationof SiberianPipit in of its separatebreeding range in easternAsia and its divergentplumage relationto the rubescenssubspedes of AmericanPipit but do not address characters.The otherthree subspecies (pacificus, ahicola, and rubescerts)the degreeof plumagevariation within American Pipit subspedes.This breedentirely within North America and western Greenland and resemble articleattempts to remedythese gaps in theliterature. Rgures4. Thistypical Siberian Pipit shows the flaring submalar sl]ipe, heavily sbeaKed underparts (especially the sides), white underparls, white eye-ring, white mediancoverts, and pale legs. Though a bitpaler ban someindividuals (cf. Figs. 8, 9), the birdis typicalin otherrespects. Photographed along the Tamu River, Tokyo,Japan 31 January1998. Photograph by TakashiKoike. VOLUblE 56 (ZOOZ), NUblBER 4 389 Figure5. Thesame Siberian Pipit as in Figure4, showingthe eye-ring and wingbars to betteradvantage. Photograph by TakashiKoike. Figure7. ThisSiberian Pipit tends toward the pale end, and the eye-ring is notespecially pronounced, but other characters indicate Siberian. Photographedin Japan in winter,date unknown. Photograph by TakashiKoike. Figure8. Thisphotograph depicts a SiberianPipit with fairly •ong contrast Rgure6. AnotherSiberian Pipit, photographed 1 December 2001 in South betweendark brown upperpads and whitish underparts, which in turn contrast Korea.They eye-dng is well-defined,likewise the coalescenceof dark withdark streaking below. The streaks of the underpadscoalesce longitudinally, streaksbelow the malararea and the starklymarked underpads against a givingthe birda stripedappearance. The white tips to themedian coveds con- whitishbackground. Photograph by KimHyun-Tae. trastnot only with the dark upperparts but also with the slightly • greater mediancoveds, a commonfeature in SiberianPipits. Photographed 15 December 1996in Japan. Photograph byTe•su Sato. 390 NORTH AMERICAN BIRDS Americanand SiberianPipits While plumagevariation within thevarious American Pipit subspecies probablyprecludes field identificationof individualsto the levelof sub- species,at leastat a reasonablelevel of confidence,separating Siberian fromAmerican Pipits in basicplumage within the contextof subspecific variationin the threeAmerican Pipit subspeciesis feasible(cf. Sibley 2000). Our analysesbelow incorporate examinations of approximately 300 museumspecimens (Museum of VertebrateZoology, University of California,Berkeley; Harvard Museumof ComparativeZoology; Los AngelesCounty Natural History Museum),hundreds of hours of field observations(primarily of AmericanPipits; several field observationsof SiberianPipit in the United States),and examinationof approximately 15 photographsof SiberianPipit. Systematicsand nomenclature In thissection, we review the historical taxonomy of the Buff-belliedPipit Figure9. Thougha bit softin focus,this photograph captures all of the fea- complexin brief(Fig. 1). In 1957,the Buff-bellied Pipit complex was con- turesof SiberianPipit nicely: the verydark streaks below, darker than the sideredconspecific with a numberof Eurasianforms under the hierarchi- upperparts'color, extend noticeably along the flanks.The streaks below the calspecies Water Pipit (A. spinoletta).Water Pipit was subsequently split malarcome together and flare to the sideof the neck,similar to Richard'sPipit into threesubspecies: Buff-bellied Pipit (A. rubescens),Rock Pipit (A. pet- (Antbusfichardi). Photographed 15 January1993 in MiyagiPrefecture, Japan. rosus),and Water Pipit (A. spinoletta)(B. O. U. 1986).Vaurie (1959), Hall (1961), andWilliamson (1965) originallysplit A. spinolettainto two eco- logicalgroups, "Water Pipits;' which breedin mountainousregions in Europe,Asia, and North America,and "RockPipits;' which breed along rockycoastlines in northwesternEurope. These two groupswere consid- ered to be separatespecies by Bannerman(1953) and Oreel (1980). However,Nazarenko (1978) showedthat two subspeciesof the "Water Pipits;'blakistoni and ]aponicus,overlapped in termsof their breeding rangein centralAsia but that theypreferred different habitats. As a result of thisstudy, Glutz (1985) brokedown the "Water Pipits" into two more species,"Water Pipit" and "Buff-belliedPipit," producing a total of three species;this split is supportedby geneticstudies as well (Zink et al. 1995). Throughoutthe 1980s,in fact,man), other authorities supported this new taxonomicarrangement: Devillers (1980), the BritishOrnithologists' Union RecordsCommittee (1986), Alstr6m and Mild (1987), and Knox (1988)all suggestedthat the entirecomplex be dividedinto threespecies: Rock (A. petrosus),Water (A. spinoletta),and Buff-belliedPipit (A. Figure10. SiberianPipits in the collectionat the Museumof Vertebrate rubescerts).Alstr6m and Mild (1996) further showedthat Rock,Water, and Zoology,Berkeley. Note the heavyventral streaking (almost striping) in all Buff-belliedPipits can be distinguished from each other based on plumage individuals,all of whichare in basicplumage. Photograph by Cin-TyLee. characters,regardless of species status. The latter is the taxonomy also cur- rentlyrecognized by theAmerican Ornithologists' Union (1989). Within eachof thesethree species, there is geographicand subspecific variation.Rock Pipit (A. petrosus)consists of nominatepetrosus--breed- ingin Ireland,Britain, and northwestern Francesand littoralis, breeding in Fennoscandiaand northwestRussia (Cramp 1988). Williamson(1965) alsorecognized two other Rock Pipit races potentially worth), of subspecif- ic status:"kleinschmidt?' (breeding on theFaeroe Islands and possiblythe outer Scottishislands) and "meinertzhageni"(breeding on the Outer Hebrides).However, the British Ornithologists' Union Records Committee (1986)did not recognizethese forms. The Water Pipit (A. spinoletta)con- sistsof threesubspecies: A. s. spinoletta,breeding in southernand central Europe;A. s.coutellii, breeding in AsiaMinor; and A. s.blakistoni, breeding in CentralAsia. The Buff-belliedPipit (A. rubescerts)complex currently consistsof A. r.}aponicus, A. r. pacificus,A. r. alticola,and A. r. rubescens. DISTRIBUTION OF SUBSPECIES IN THE RUFF-RELLIED PIPIT COMPLEX Figure11. AmericanPipits of the subspeciespacificus in the collectionat Breedingrange Museumof VertebrateZoology, Berkeley. The comparatively light streaking The breedingand wintering ranges of the four subspeciesof Buff-bellied (almostspotting) of thesebirds never coalesces into a longitudinally"striped" Pipitare poorly understood owing to difficultyin subspecificidentifica- appearancebelow, nor is the contrastwith the underpartsquite as st•oogas tion. in Siberian.Photograph by Cin-TyLee. VOLUME 56 (2002), NUM•œR 4 391 The SiberianPipit (A. r.japonicus) breeds in centraland eastern Siberia from Tunguskato Kamchatkaand south to northernSakhalin and the Kurile