NOTES NORTHERN SAW-WHET OWL IN THE SIERRA SAN PEDRO TIR: FIRST BAJA CALIFORNIA RECORD RICHARD A. ERICKSON, LSA Associates,1 Park Plaza, Suite 500, Irvine, Califor- nia 92714 ALAN D. BARRON 2460 MacielLane, CrescentCity, California95531 THOMAS E. WURSTER 278 Santa Anita Court, Sierra Madre, California91024 On the evening of 5 July 1993, we discovereda Northern Saw-whetOwl (Aegoliusacadicus) at approximately2300 m elevationin the Sierra San Pedro Mfirtir, Baja California(Norte). We found the bird near kilometermarker 86 while owlingalong the main road throughParque Nacional Sierra de San Pedro Mfirtir, about2 km eastof La Coronade Arriba.At thispoint the mainroad from the west descendedsteeply into a canyonseparating La Coronade Arribafrom the higher meadowsat Vallecitosto the east.The habitatwas relatively open mixed coniferous forestcomposed of JeffreyPine (Pinusjeffreyi), White Fir (Abiesconcolor), and SugarPine (Pinuslarnbertiana), with littleground cover. A smallgrove of Quaking Aspen (Populustremuloides) occupied the canyonbottom. It was cool and still underclear skies, with a nearlyfull moonjust above the horizonwhen we foundthe owl. At approximately2200 hours,the owlfirst responded to ourwhistling with a single loudhigh-pitched "scree" note. In ourexperience, this response is typicalof the Saw- whet Owl andwe tentativelyidentified the birdfrom this note. We were convincedof its identityonly after the owl beganto givethe normalsong of thisspecies. Over the nexthalf hourwe heardan estimatedsix bouts of singingas the birdmoved over an area of about0.5 ha. Singingconsisted of a monotonousseries of singlenotes at a mediumpitch, given at a rateof approximatelytwo notesper second.Singing bouts lasted 1 to 4 minutes. We heardthe birdfrom as dose as 6-7 m andtried to seeit withflashlights, but the bird remainedconsistently out of sight in the dense foliage of firs where we pinpointedthe soundseveral times at heightsof 4-7 m. Nevertheless,we saw it twice,briefly. Erickson saw the birdin silhouette,without light, as it swoopedtoward hisface in responseto squeakingand squealingsounds. He notedonly its smallsize and compactshape. Barron saw what wasapparently the bird,also in silhouetteonly, and withoutlight, as it flew overthe road abovehim. Barronand Ericksonare veryfamiliar with the vocalizationsof the NorthernSaw- whetOwl fromdozens of encounterswith the speciesover the previous25 years,the mostrecent in March 1993. Erickson'sexperience is limitedto California,whereas Barron'sranges from the westernU.S. to the prairie provincesand the Appala- chians.Wurster was aware of the typicalsong but had neverheard the speciesin life. This individualsounded consistently "hoarser" (less clear) and softerthan most birds we hadpreviously heard, but the patternand pitch of the callswere perfect, and left no doubtin our mindsas to the identityof the bird. "Hoarse"individuals of several speciesof owlshave been heard on occasionin California(J. Winterpers. comm.), and R. Stallcup(in litt.)has heard a singleSaw-whet Owl in Californiachange from hoarseto clearnotes in mid-series.The causeand/or significance of thisis unknown to us. The only likely sourceof confusionwith vocalizationsof this speciesis the NorthernPygmy-Owl (Glaucidium gnoma). Except in the caperegion, home of the distinctiveendemic subspecies G. g. fioskinsii,the Northern Pygmy-Owlhas not beenadequately documented in BajaCalifornia (Grinnell 1928, AOU 1983, Wilbur 66 WesternBirds 25:66-68, 1994 NOTES 1987, Howell and Webb in press).We do not considerWauer's (1992: 86) brief mentionof a bird heard only (Wauerpers. comm.)or the map of this species publishedby NGS (1987) to be conclusive.Three things,in our experience,distin- guishedour bird from a NorthernPygmy-Owl: (1) althoughthe pitch of individual Pygmy-Owlnotes can be verysimilar to thoseof the Saw-whetOwl, andPygmy-Owls cangive notes in rapidsuccession for a shortperiod, we havenever heard them give identicalnotes in thismanner for minutesat a time as istypical of the Saw-whetOwl; (2) we havenot heardanything like the "scree"note described here from the Pygmy- Owl; and(3) Pygmy-Owlsnormally call at twilight,or evenin daylight,but rarely late at night. Northern Saw-whet Owls are found across much of North America from Alaska southto Oaxaca,but there are no previousrecords from Baja California(Grinnell 1928, AOU 1983, Wilbur1987, Howelland Webbin press).The speciesis rare to uncommonand local in montane southernCalifornia, including the Palomar and Cuyamacamountains of San Diego County(Garrett and Dunn 1981, Unitt 1984). Thus,the SierraSan PedroM•rtir representsa rangeextension of approximately 250 kin. Habitatsuitable for thisspecies is extensivein the SierraSan PedroM•rtir, and futurerecords may reveala breedingpopulation. An alternativeexplanation is thatour bird was merely the remnantof an irruptionof Saw-whetOwls into the area. Monsonand Phillips(1981) statedthat in Arizona "irruptionsin somewinters bring largenumbers to a region,where they may stayfor a few yearsand nest."Saw-whet Owls were unusuallynumerous in the Kayentaarea of NavajoCounty in northern Arizonain springand summer 1993, anda rare lowlandrecord was established in the Phoenixarea in latewinter 1993 (G. H. Rosenbergpers. comm.), so our record may be related.Similar irruptions have not beendetected in southernCalifornia, although apparentfluctuations in numbersin the San GabrielMountains could be the resultof them (K. L. Garrettpers. comm.). The Northern Saw-whetOwl is but the latestof a numberof speciesfirst found summeringin the Sierra San Pedro M•rtir in the lastdecade (R. E. Websterand Wursterpers. ohs.; Howell and Webb 1992). Additionalinvestigations will likely revealsome of thesespecies in the SierraJuarez as well. We thank Kimball L. Garrett, Steve N. G. Howell, M. W. (Bill) O'Connell, Rich Stallcup,Philip Unitt, and Jon Winter for providinghelpful comments on various draftsof thisnote, and RobertA. Hamiltonfor logisticalsupport. LITERATURE CITED AmericanOrnithologists' Union. 1983. Check-listof North AmericanBirds, 6th ed. Am. Omithol. Union, Washington,D.C. Garrett, K., and Dunn, J. 1981. Birdsof SouthernCalifornia: Status and Distribu- tion. LosAngeles Audubon Soc., LosAngeles. Grinnell,J. 1928. A distributionalsummation of the ornithologyof LowerCalifornia. Univ. Calif. Publ. Zool. 32:1-300. Howell, S. N. G., and Webb, S. 1992. Noteworthybird observationsfrom Baja California,Mexico. W. Birds23:153-163. Howell, S. N. G., and Webb, S. In press.A Guideto the Birdsof Mexicoand NorthernCentral America. Oxford Univ. Press,Oxford, England. Monson,G., and Phillips,A. R. 1981. AnnotatedChecklist of the Birdsof Arizona, 2nd ed. Univ. Ariz. Press, Tucson. NationalGeographic Society. 1987. FieldGuide to the Birdsof NorthAmerica, 2nd ed. Natl. Geogr.Soc., Washington,D.C. 67 NOTES Unitt, P. 1984. The birdsof San DieõoCount•. San DieõoSoc. Nat. Hist. Memoir 13. Wauer,R. H. 1999..A Naturalist'sMexico. Tex. A&M Univ.Press, Colleõe Station. Wilbur,S. R. 1987. Birdsof BajaCalifornia. Univ. Calif. Press, Berkeley. Accepted22 October1993 Northern Saw-whet Owl Lithographby Linda $chllesmanErickson 68 .