THE SUBSPECIES of the NORTHERN SAW-WHET OWL on the QUEEN CHARLOTTE ISLANDS: an ISLAND ENDEMIC and a NONBRING Visrrant
THE SUBSPECIES OF THE NORTHERN SAW-WHET OWL ON THE QUEEN CHARLOTTE ISLANDS: AN ISLAND ENDEMIC AND A NONBRING vISrrANT SPENCER G. SEALY, Departmentof Zoology,University of Manitoba,Winnipeg, Manitoba R3T 2N2, Canada Two stronglydifferentiated subspecies of the Northern Saw-whet Owl (Aegoliusacadicus) are recognizedby the AmericanOrnithologists' Union (1957), A. a. brooksi, restrictedto the Queen Charlotte Islands(known also as Haida Gwaii), British Columbia, and nominate acadicus, widespread elsewhere in North America. I examinedspecimen and photographicrecords of the subspeciesof the Northern Saw-whet Owl from the Queen Charlotte Islandsand nearby BritishColumbia and Alaskato determinethe extentof the rangeof brooksi and determine the seasonaldistribution of nominate acadicus on the Queen Charlotte Islands.Records of acadicus on the Queen Charlotte Islandshave not been compiled,and the inter-islanddistribution of brooksihas not been ascertained.Godfrey (1986:328) stated that Northern Saw-whet Owls (presumablybrooksi) occur in "the northernQueen CharlotteIslands," but the entire archipelagowas shadedon his rangemap. Cowan (1989) stated that brooksiis foundonly on Grahamand Moresbyislands, the two largest islandsof the archipelago. The Queen CharlotteIslands comprise the most isolatedarchipelago off the Pacificcoast of Canada.The islandsare separatedfrom the mainlandof British Columbiaby about 80 km and from the nearestAlaska islands, Forresterand Dall, by about70 km and 50 km, respectively.The isolationof the Queen CharlotteIslands is reflectedin their beingthe home of several endemic subspecies,some stronglydifferentiated. Seven have been de- scribedso far: in addition to A. a. brooksi, ?icoides villosus picoideus (Osgood,1901)(Hairy Woodpecker), Cyanocitta stelleri carlottae Osgood, 1901 (Steller'sJay), Certhia familiaris stewar.tiWebster, 1986 (Brown Creeper),Catharus ustulatusphillipsi Ramos,1991 (Swainson'sThrush), Ixoreus naevius carlotte (Phillips, 1991) (Varied Thrush), and Pinicola enucleatorcarlottae Brooks,1922 (PineGrosbeak).
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