j Raptor Res. 27(3):154-160 ¸ 1993 The Raptor ResearchFoundation, Inc. PRESENCE AND DISTRIBUTION OF MEXICAN OWLS: A REVIEW PAULA ENRiQUEZ-ROCHA GEB-Mex, Ap. Postal4-077, 06400 M•xico, D.F., M•xico j. Luis RANGEL-SALAZAR Departamentode EcologœaTerrestre, CIQRO, Ap. Postal424, 7700 Chetumal,Quintana Roo, Mdxico DENVER W. HOLT Ozol ResearchInstitute, P.O. Box 8335, Missoula, MT 59807 U.S.A. ABSTR^CT.--Mexicohas a rich owl assemblage,represented by 27 species.Eighteen of thesespecies occur in theNearctic and Neotropical regions, and nine species occur only in theNeotropical region. Their biology, ecologyand distribution,however, are poorly known. We recorded3683 specimenscollected between 1840 and 1991 from 11 nationaland 37 foreignmuseums, and reviewedthe literature concerningthese owls.From thesedata we presenta more unifieddistribution of Mexican owls.Four species,Barn Owl (Tyro alba), Great Horned Owl (Bubovirginianus), Ferruginous Pygmy-Owl (Glaucidiumbrasilianum) and Burrowing Owl (Speotytocunicularia), have a wide distribution. The Balsas ScreechOwl (Otus seductus)is endemicto the centralPacific region. Oaxaca and Michoacanhad the highestowl species richnesswith 21 and 19 species,respectively. Aguascalientes, Campeche and Tlaxcala had the lowest owl speciesrichness, four, five, and five respectively.The FerruginousPygmy-Owl was the mostcollected owl, representing30.7% of the specimens,and the UnspottedSaw-whet Owl (Aegoliusridgwayi) the least with 0.19%.Of the Neotropicalspecies, the UnspottedSaw-whet Owl, StripedOwl (Asioclamator), and StygianOwl (A. stygius)are consideredendangered by the Mexicangovernment. The screech-owlgroup (Otus)and the Barred Owl (Strix varia)/FulvousOwl (S. fulvescens-- S. v. fulvescens)have uncertain distributions due to taxonomic uncertainties. Presenciay distribuci6nde los bfihosMexicanas: una revisi6n RESUMEN.--M•xicotiene una alta riquezade especiesde bfihos,representada pot 27 especies.Dieciocho de estasespecies se encuentran tanto en la regionneirtica comoen la neotropical,y nuevede las especies selocalizan solo en la regi6nneotropical. Su biologla,ecologla asl comosu distribuci6nes poco conocida. Nosotroscompriamos 3683 datosde especlmenesde bfihoscolectados en Mgxico;con registros desde 1840 hasta 1991, de 11 museosnacionales y de 37 extranjeros,adicionalmente revisamos intensamente la literatura disponible.Combinando estos datos, damos una distribuci6nunificada de los bfihosde Mgxico. Cuatroespecies, la Lechuzade Campanario(Tyto alba), el BfihoCornado Americano (Bubo virginianus), el TecolotitoBajefio (Glaucidium brasilianum) y el TecoloteZanc6n (Speotytocunicularia) tienen una amplia distribuci6nen el continenteAmericano. E1 TecoloteOjioscuro del Balsas(Otus seductus) es endgmicopara la regi6ndel PacificoCentral de Mgxico.Los estados de mayor riqueza de especies fueron Oaxacay Michoacincon 21 y 19 especiesrespectivamente, por el contrariolos estados con menor riqueza fueronAguascalientes, Campeche y Tlaxcalacon 4, 5 y 5 respectivamente.El TecolotitoBajefio ha sido la especiede bfihomils colectada, representando el 30.7% de los especlmenes, y el queregistro con menos colectasfug el TecoloteAbetero Surerio (Aegolius ridgwayi) representando tan solo el 0.19%.De lasespecies neotropicales,el TecoloteAbetero Surerio, el BfihoCornado Cariblanco (Asio clamator) y el BfihoCornado Oscuro(A. stygius)son consideradas como amenazadas por el gobiernoMexicano. E1 grupoOtus asi comoel BfihoSerrano Vientrirrayado (Strix varia)/Bfiho Serrano Surerio (S. fulvescens = S. v.fulvescens) tienen distribuciones controversiales debidas a su clasificaci6n incierta. [Traducci6n Autores] Currently, there are 178 speciesof owls recog- forests,north of 35ø (Norberg 1987). Although,there nized in the world (Sibley and Alhquist 1990), of is someoverlap. which 27 (15%) speciesoccur in Mexico. This ex- Owls in Mexico have been little studied and most ceedsthe owl speciesdiversity (N = 22) of northern literature is old (Ridgway 1895, Kelso and Kelso 154 SEPTEMBER 1993 MEXICAN OWL DISTRIBUTION 155 Sonora Chihuahua aa Coahuila Californi, Sur Si Durango dipas 1. Aguascalientes 2. OistritoFederal •,,N• Gulf of 3. Guanajuato Mexico 4.5. MorelosHidalgo • IRa 6. Queretaro Colinn :ruz 7. Tlaxcala Guerrero Pacific Ocean Oaxaca Chiapas Figure 1. Map of the Mexican Republic showinglocations of 32 states. 1936, Moore 1937a, 1937b, 1941, 1947a, Moore choacfin,Escuela Nacional de CienciasBio16gicas, Insti- and Peters 1939, Alvarez del Toro 1949, Briggs tuto de Historia Natural de Chiapas, Instituto Nacional 1954, Moore and Marshall 1959, Buchanan 1964, de InvestigacionesForestales y Agropecuarias-Bacalar, Instituto Nacional de Investigacionessobre Recursos B•6- Northern 1965). Generally,most Mexican owl spe- ticos,Laboratorio Natural de Las Joyas, Universidad de cieshave limited morphologicaldescriptions and only Guadalajara, Museo de Zoologlade la Facultad de Cien- approximateddistributions (Friedman et al. 1950, cias, Museo de Zoologla Iztacala, Sa16nde las Aves de Blake 1972, Davis 1972, Peterson and Chalif 1973, Saltillo Coahuila,Universidad Aut6noma de Baja Cali- fornia Sur and 37 foreignmuseums (Australian Museum, 1989, Edwards 1989). Unfortunately,these distri- AnnistonMuseum of Natural History, Academyof Nat- butionsare often controversial.Here, we presenta ural Sciencesof Philadelphia,Bell Museum of Natural review of the distribution and relative status of Mex- History, British Museum, Carnegie Museum of Natural ican owls based on museum specimen data and History, Cornell University Collection,Collection Zool- available literature. ogy Museum Amsterdam-Nederland, Denver Museum of Natural History, Delaware Museumof Natural History, Fort Hays Museum,Florida Museumof Natural History, STUDY AREA AND METHODS Forschungsinstitutund Naturmuseum Senckenberg, Har- Mexico (2 million km2) has32 states(Fig. 1) with > 50% vard Museumof ComparativeZoology, Illinois StateMu- of the land mass above 1000 m elevation (Ramos 1985). seum Collection,Kansas University Collection,Los An- Its 32 vegetationtypes (Rzedowski 1986), geographiclo- gelesCalifornia Museum-Natural History, LouisianaState cation, and topography contribute to a rich diversity of UniversityMuseum Zoology,Moore Laboratoryof Zo- fauna and flora. ology-OccidentalCollege, Museo Nacional de Ciencias To obtain information on Mexican owl specimenswe Naturales-Espafia,Museum of Natural History-Chica- wrote letters to or visited 11 national museums (Colecci6n go, Museum of Vertebrate Zoology-Universityof Cali- Ornitol6gicadel Instituto de Biologla,Colecci6n Ornito- forniaBerkeley, Oklahoma Museum of Natural History, 16gicade San Nicol•tsde Hidalgo, Universidadde Mi- ProvincialMuseum of Alberta, PeabodyMuseum Col- 156 ENRiQUEZ-ROGHAET AL. VOL. 27, NO. 3 lection-YaleUniversity, Royal Ontario Museum, Rijks- museumVan Naturvlijke Historie-Leiden, SantaBarbara MuseumofNatural History, Southwestern College Col- Sr^TESø• lection,San Diego Museum of Natural History, Staatli- 0 O0 0 0 0 0 0 XO O0 O0 chesMuseum ftir Naturkundein Stuttgart,Texas Co- Bcs 0 O0 0 XO O0 O0 operativeWildlife Collection,National Museum of Natural 0 X 0 0 0 History-SmithsonianInstitute, University of Washington, c.,. O0 O0 0 O0 O0 OOOX 000 Thomas Burke Memorial State Museum, Universityof c.•s 0 0000000000 0 O0 0 OOX WisconsinZoological Museum, Western Foundation Ver- co^ O0 O0 0 O0 XOO0 O0 cot 0 0 000 0 O0 OXXOOO0 tebrate Zoology Collection,Zoological Institute of the 0 O0 0 0 0 OXO XO 0 X Academyof Sciences-URSS).Additionally, we reviewed OF O0 O0 0 0 0 XOO0 O0 the existingliterature for informationconcerning Mexican O0 0 XO 0 0 O0 0 0 0000 000 owls. For vegetationtypes, we followedRzedowski (1986). 0 0 0 0 000 O0 State boundarieswere the unit usedto delineatedistri- XO O0 X 0 0 0 O0 O0 O0 0 0 O0 000 O0 OX 000 butionsof the owls. We applied the taxonomyused by O0 0 O0 O0 X 0 OXO0 XO Amadonand Bull (1988) for mostof the owl specieswhich O0 O0 000 0 O0 000 XOOO0 O0 occurin Mexico. We followed Marshall et al. (1991) for •oR O0 0 O0 0 00000 0 0 0 0 O0 0 0000 recentchanges of VermiculatedScreech-Owl (Otus gua- OX O0 0 O0 O0 OOX 0 temalae)to Variable Screech-Owl(O. atricapillus),and o•x O0 0 O0 0000000 0 O0 OOXO X A.O.U. (1991) for genericchange of the BurrowingOwl O0 X O0 XO0 0000 X from Atheneto Speotyto.We includedthe Fulvous Owl 0 OX 0 0 0 0 O0 X 0 0 000 0 X 0 X (Strixfulvescens) as a subspeciesof the BarredOwl (Strix o•oo O0 O0 0 0 O0 0 0000 0 varia) = S. v.fulvescens (Edwards 1989, J. Marshall pers. O0 0 0 OOOOXO O0 0 O0 comm.). son O0 O0 0 0 O0 O0 0000 0 TAB 0 XO XO O0 0 RESULTS •^• 0 O0 0 0 O0 000XO 0 0 TLAX O0 0 0 0 We compiledand analyzeddata on 3683 speci- O0 0 0000000 0 O0 OX OOXX 0 0 O0 0 0 X X mensof Mexicanowls. Twenty-seven Mexican owl Yuc 0 0 0 0 000 speciesfrom boththe Nearcticand Neotropicalzoo- geographicregions are represented.Eighteen species Figure 2. Presenceof owl speciesby state in Mexico. occurin the Nearcticand Neotropicalregions, while Codesare describedin the text. (O = museum recordsand nine speciesoccur only in the Neotropicalregion. X = literature records.) The Balsas Screech-Owl (Otus seductus)is endemic to Mexico's Pacific slope region. The Bearded sula. Blake (1972) and Grossmanand Hamlet (1988) Screech-Owl(Otus barbarus)and UnspottedSaw- consideredthem widely distributed throughout whet Owl (Aegoliusridgwayi) are found only in Mexico. Chiapas. The greatestnumber of museumspecimens were Flammulated Owl (OFLA) Otusfiamrneolus of the FerruginousPygmy-Owl (Glaucidiumbrasi- Flammulated Owl