IDENTIFICATION AND DISTRIBUTION IN CALIFORNIA OF THE SPHYRAPICUS VARIUS GROUP OF SAPSUCKERS Pierre Devillers INTRODUCTION In his recent paper on avian hybridization,Short (1969) recommendedthat the three sapsuckers,Yellow-bellied Sphyrapicus varius,Red-naped S. nuchalis,and Red-breastedS. tuber be treatedas distinct species,thus opening a new chapter in a long controversy. S. tuber was describedas a new speciesin 1788 by Gmelin. Ridgway was the first to suggestits subordinationto S. variusin 1872 and againin 1873 and 1874. In his "Birdsof North andMiddle America" (1914) he returnedto treatingit as a distinctspecies. Meanwhile the A.O.U. Check-listhad retainedthe full speciesstatus in its three first editions(1886, 1895 and 1910), changingto a racialtreatment in the fourth edition, in contrastwith Ridgway'sown changeof mind. S. nuchalis,described by Baird in 1858, wassubsequently treated as a race of pariusby most authorities,starting with Couesin 1872 and Ridgwayin 1873, but Ridgwayincluded a note of warningin "Birds of North and Middle America",writing, "...I believethat it wouldbe betterto consider[nuchalis] as specificallydistinct from S. parius." The main issuewas alreadythe interpretationof the "intermediates" or "hybrids". Grinnell(1901), for instance,claimed to see"continuous intergradation"between S. pariusand S. tuber throughS. nuchalis,a view opposedby Ridgwaybut one whichpresumably weighed heavily in the later decisionof the A.O.U. Clearly,arguments over specimens couldnot leadanywhere, and careful study of the contactsbetween the formswas required, a needwhich was partially filled by Howell(1952). After studyingin detail the contactsbetween the Red-breastedand the Red-napedSapsuckers and summarizingthe very scantyinformation availableon the contactsbetween the Yellow-belliedSapsucker and the other forms, Howell supportedthe then currenttreatment of the A.O.U., consideringthe three formsas conspecific.Dickinson (1953), Calif. Birds 1: 47-76, 1970 47 SAPSUCKER IDENTIFICATION & DISTRIBUTION on the contrary, found convincingevidence for retainingruber as a distinctspecies in his analysisof BritishColumbia material. Apparently little further progresswas made in the field, but in 1969, Short, in the course of a general reassessmentof the taxonomic implications of hybridization,applied his criteria to Howell's information and thus reversed the latter's decision. A resultof the long treatmentof the three formsas races of one species,is the completelack of informationon identificationin field guidesand a consequentconfusion as to the statusof the various formsin severalareas. In California,for instance,there is a widespread belief that most birds are "intermediates",resulting in reluctanceof field observersto make positiveidentification of these forms,finally leadingto ignoranceof their comparativedistribution and abundance, and failureto recognizereal hybrids or ascertaintheir frequency. Even specimensare misidentified,sometimes in a manner that approaches the unbelievable. It seems warranted, therefore, to summarize the problemsrelated to the identificationof the three sapsuckers,their distribution,and the frequencyof hybrids. Throughout the paper S. varius,S. nuchalis, and S. ruber are consideredas distinctspecies, as suggestedby Short (op. cit.). This treatmentis alsofollowed by McCaskie,Devillets, Craig, Lyons, Cough- ran, and Craigin the CaliforniaChecklist (1970). This choicewill be furtherexplained in the paragraphdevoted to thecontacts between the species. GENERAL DISTRIBUTION As a backgroundto the discussion,an outline of the general distributionis presentedhere, condensedfrom Howell (1952), the A.O.U. Check-list(1957), Godfrey (1966), Griscomin Miller et al (1957), and variousother sources which are quotedwhere relevant. Designationsof the biomesare those of Shelford(1963), andare cap- italized. The Yellow-belliedSapsucker breeds in the southernhalf of the trans-continental Boreal Coniferous Forest belt and in the Northern TemperateDeciduous Forest of the easternUnited Statesand Canada. 48 SAPSUCKER IDENTIFICATION & DISTRIBUTION In the West its rangeextends to southernYukon and includesnorth- eastern British Columbia (Peace River Valley) and westernAlberta (east of the Rockies). Within this regionit occursin deciduousor deciduous-coniferousstands, particularly where poplars and birches are important constituents. It winters throughoutthe southeastern United States and Central America, north to about 40 degrees latitude, west to central Oklahoma(Sutton, 1967), easternTexas, easternCoahuila, southern Durango, and southernSinaloa. It is of irregular occurrencein southern Arizona (Phillips, Marshall, and Monson,1964). The Red-naped Sapsuckeris characteristicof the Montane ConiferousForest regionof westernNorth America(excluding the Sierra Nevada). It breeds north to southeasternBritish Columbia and southwesternAlberta, west to the eastdope of the Cascadesand a few points on the east dope of the SierraNevada, south to central Arizona(Phillips et al, 1964) and the MogollonMountains of southern New Mexico(Hubbard, 1965). Outsidethe rangemapped by Howell, it has been found nestingin the Black Hills of South Dakota by W. and K. Eastman(Gammell and Huenecke,1954; Gammell, 1956; no supportingdetails). It breedsin forestscontaining aspen or aspen mixed with conifers,more rarelyin predominentlyconiferous forests. It wintersin southernCalifornia, most of Arizona(except the north- west),southern New Mexico,the wholeof BajaCalifornia, and the northwesternpart of the Mexicanmainland. The Red-breastedSapsucker has two well differentiatedraces. The northernrace, S. tubertuber, is practicallylimited to the Rainy WesternHemlock Forest of the northernPacific coast, occurring from southeasternAlaska to southernOregon, and extendingeast of the Cascadesat a few pointsin Oregonand Washington, aswell as inland in British Columbia to the Peace River Parklands. It winters in the coastal part of its range. The southernrace, S. tuber daggetti,breeds in a smallregion of the southernpart of the samebiome in northwestern Californiaas well asin the Cascadesof southernOregon, the Sierra Nevada,and the highermountains of southernCalifornia. It is a bird of aspen-ponderosapine association,except in its restrictedcoastal range. It wintersat lower elevationsthroughout California and in northwesternBaja California. It is evidentfrom this that the three species have different migrat- inghabits, varius being a longdistance migrant, nuchalis intermediate, and ruber a shortdistance migrant, the northernrace almost resident. 49 4 Red-naped SapsuckerS. nuchalis, presumed female, at nest hole in an aspen, westernWyoming, July 1969. Photoby HerbertClarke. 50 $! SAPSUCKER IDENTIFICATION & DISTRIBUTION NATURE OF THE CONTACTS This sectionis a summaryof the informationgathered by Howell; its purposeis to furtherexplain why the three formsare treatedas distinctspecies; in additionit will clarifyviews about prevalence and significanceof hybrids. THE RACES OF R UBER The two forms, tuber and daggetti, meet in southernOregon betweenKlamath Lake and the coast. Inland the replacementis rather abrupt, but in the coastalregion there is apparently progressive intergradationwhich justifies the treatmentof the two formsas con- specific. All intermediatescan thusbe expected,both in the contact areaand in the winter rangeof daggetti. CONTACTS OF VARIUS WITH THE OTHER TWO FORMS Next to nothingwas known about the possiblecontacts of the Yellow-belliedSapsucker with the other two speciesat the time of Howell'sstudies; he did not investigatethem himself, and, as far asI know, they have not yet been studied. This remainsthe main gap in our knowledgeof the complexand one whichwill haveto be filled beforeany reasonablycertain conclusions can be drawn. The Yellow- belliedand Red-napedSapsuckers are presumedto comein contactin westernAlberta but the regionhas not beencritically explored; it is further assumed,because of the scarcityof possiblehybrids in seriesof birdstaken on migrationor in winter,that interbreedingis very limited (Howell listssix possible hybrids). S. variusdefinitely comes in contact with S. tuber tuber in northern British Columbia, in the Peace River Parklands. Prior to Howell's study there had been two observations in that region,one (Swarth,1922) includingan apparentmixed pair observed(varius + variusx tuber) and a lone hybrid collected,the other(Cowan, 1939) a pair of typicaltuber breeding within eight feet and fifty feet, respectively,of two pairsof varius. I havebeen able to trace only two recent observations,both merely indicatingthe pre- senceof loneYellow-bellied Sapsuckers in the knownrange of the Red- breasted,north of PrinceGeorge (Rogers, 1968 and 1969). No hybrids are known from the migrationroutes, but they couldbe confusingly similarto nuchalisx tuberor nuchalisx daggettihybrids, or eventypical 52 SAPSUCKER IDENTIFICATION & DISTRIBUTION nuchalis,as indicatedby the specimentaken by Swarth,described by Howell. CONTACTS OF NUCHALIS AND R UBER The rangesof S. nuchalisand S. ruber daggetticome in contact alongthe easternslope of the Cascade-Sierraranges from southernOre- gon to central California. The overlap regionis alwaysvery narrow. The contact wasstudied in detail by Howell in ModocCounty, extreme northeasternCalifornia. He found the overlapregion to be about forty miles wide; at a point in the middle of this area,he found the following repartition for a sample of forty-two individuals: eight typical nuchalis,fourteen typical daggettiand twenty