Michael A. Bogan

STABLE HYDROGEN ISOTOPE ANALYSIS OF BAT HAIR AS EVIDENCE FOR SEASONAL MOLT AND LONG-DISTANCE MIGRATION

Abstract Although hoary bats (Lasiurus cinereus) are presumed to be migratory and capable of long-distance dispersal, traditional marking techniques have failed to provide direct evidence of migratory movements by individuals. We measured the stable hydrogen isotope ratios of bat hair (δDh) and determined how these values relate to stable hydrogen isotope ratios of precipitation (δDp). Our results indicate that the major assumptions of stable isotope migration studies hold true for hoary bats and that the methodology provides a viable means of determining their migratory movements. We present evidence that a single annual molt occurs in L. cinereus prior to migration and that there is a strong relationship between δDh and δDp during the molt period. This presumably reflects the incorporation of local δDp into newly grown hair. Furthermore, we present evidence that individual hoary bats are capable of traveling distances in excess of 2,000 km and that hair is grown at a wide range of latitudes and elevations. Stable hydrogen isotope analysis offers a promising new tool for the study of bat migration.

EFFECT OF ELEVATION ON DISTRIBUTION OF FEMALE BATS IN THE BLACK HILLS, SOUTH DAKOTA

Abstract Presumably, reproductive female bats are more constrained by thermoregulatory and energy needs than are males and nonreproductive females. Constraints imposed on reproductive females may limit their geographic distribution relative to other bats. Such constraints likely increase with latitude and elevation. Males of 11 bat species that inhabit the Black Hills were captured more frequently than females, and reproductive females typically were encountered at low-elevational sites. To investigate the relationship between female distribution and elevation, we fitted a logistic regression model to evaluate the probability of reproductive-female capture as a function of elevation. Mist-net data from 1,197 captures of 7 species revealed that 75% of all captures were males. We found a significant inverse relationship between elevation and relative abundance of reproductive females. Relative abundance of reproductive females decreased as elevation increased. Reproductive females may be constrained from roosting and foraging in high-elevational habitats that impose thermoregulatory costs and decrease foraging efficiency. Failure to account for sex differences in distributional patterns along elevational gradients may significantly bias estimates of population size.

SYSTEMATICS OF MYOTIS OCCULTUS (CHIROPTERA: VESPERTILIONIDAE) INFERRED FROM SEQUENCES OF TWO MITOCHONDRIAL GENES

Abstract The systematic relationship between Myotis lucifugus carissima and Myotis occultus has been the subject of multiple studies. Although several studies, including a recent allozyme study, concluded that M. occultus is a subspecies of M. lucifugus, this view has not been universally accepted. We reexamined the relationships of these 2 taxa by sequencing the mitochondrial cytochrome-b (cyt-b) and cytochrome oxidase II (COII) genes of specimens from the allozyme study. The results suggest that M. occultus represents an evolutionarily distinct monophyletic lineage and provide support to arguments that M. occultus is a distinct species.

GEOGRAPHIC VARIATION IN THE BLACK BEAR (URSUS AMERICANUS) IN THE EASTERN UNITED STATES AND CANADA

The pattern of geographic variation in morphologic characters of the black bear (Ursus americanus) was assessed at 13 sites in the eastern United States and Canada. Thirty measurements from 206 males and 207 females were recorded to the nearest 0.01 mm using digital calipers and subjected to principal components analysis. A matrix of correlations among skull characters was computed, and the first 3 principal components were extracted. These accounted for 90.5% of the variation in the character set for males and 87.1% for females. Three-dimensional projection of localities onto principal components showed that, for males and females, largest individuals occurred in the more southern localities (e.g., males-Louisiana-Mississippi, eastern Texas; females-Louisi- ana-eastern Texas) and the smallest animals occurred in the northernmost locality (Quebec). Gen- erally, bears were similar morphologically to those in nearby geographic areas. For males, correla- tions between morphologic variation and environmental factors indicated a significant relationship between size variation and mean January temperature, mean July temperature, mean annual precip- itation, latitude, and actual evapotranspiration; for females, a significant relationship was observed between morphologic variation and mean annual temperature, mean January temperature, mean July temperature, latitude, and actual evapotranspiration. There was no significant correlation for either sex between environmental factors and projections onto components II and III.

EXAMINING PATTERNS OF BAT ACTIVITY IN BANDELIER NATIONAL MONUMENT, NEW MEXICO, BY USING WALKING POINT TRANSECTS

Abstract We conducted a preliminary study using small field crews, a single Anabat II detector coupled with a laptop computer, and point transects to examine patterns of bat activity at a scale of interest to local resource managers. The study was conducted during summers of 1996–1998 in Bandelier National Monument in the Jemez Mountains of northern New Mexico, a landscape with distinct vegetation zones and high species richness of bats. We developed simple models that described general patterns of acoustic activity within 4 vegetation zones based primarily on nightly variation and a qualitative index of habitat complexity. Bat acoustic activity (number of bat passes&sol point) did not vary dramatically among a limited sample of transects within a vegetation zone during 1996. In 1997 and 1998, single transects within each vegetation zone were established, and bat activity did not vary annually within these zones. Acoustic activity differed among the 4 vegetation zones of interest, with the greatest activity occurring in riparian canyon bottomland, intermediate activity in coniferous forest and a 1977 burned zone, and lowest activity in piñon-juniper woodlands. We identified 68.5% of 2,529 bat passes recorded during point-transect surveys to species using an echolocation call reference library we established for the area and qualitative characteristics of bat calls. Bat species richness and composition differed among vegetation zones. Results of these efforts were consistent with general knowledge of where different bat species typically forage and with the natural history of bats of New Mexico, suggesting such a method might have value for drawing inferences about bat activity in different vegetation zones.

Taxonomic status of Myotis occultus

The taxonomic status of the Arizona myotis ( Myotis occultus ) is uncertain. Although the taxon was described as a distinct species and currently is regarded as such by some authors, others have noted what they interpreted as intergradation with the little brown bat ( M. lucifugus carissima ) near the Colorado-New Mexico state line. In this study, we used protein electrophoresis to compare bats of these nominal taxa. We examined 20 loci from 142 specimens referable to M. occultus and M. lucifugus from New Mexico, Colorado, and Wyoming. Nine of the 20 loci were polymorphic. Results show that there were high similarities among samples, no fixed alleles, and minor divergence from Hardy-Weinberg equilibrium. Our results suggest that the two nominal taxa represent only one species and that M. occultus should be regarded as a subspecies of M. lucifugus .

Does variation in cranial morphology of Myotis occultus (Chiroptera: Vespertilionidae) reflect a greater reliance on certain prey types?

Few studies have investigated the relationship between morphological variation and local feeding habits of bats in the United States. We used discriminant function analysis (DFA) to compare cranial morphology of Myotis occultus from southern Colorado, and central, and southern New Mexico. We analyzed guano collected from maternity colonies in southern Colorado and central New Mexico to compare food habits. Bats from southern Colorado had the smallest values on the first canonical variate (CV1) that also reflected the smallest measurements of key cranial and dental variables, including height of coronoid process, width of molar, and dentary thickness. Bats from central and southern New Mexico had intermediate and large CV1 values, respectively. Overall, CV1 discriminated individuals occurring in southern Colorado and central New Mexico from those in southern New Mexico. CV2 served best at discriminating bats of southern Colorado from those of central New Mexico. Comparison of food habits revealed that individuals from southern Colorado ate more soft-bodied prey items (e.g., flies) whereas bats from central New Mexico ate more hard-bodied prey items (e.g., beetles). As shown in earlier studies that investigated relationships between morphology and diet of insectivorous bats, we found differences in skull morphology of M. occultus that were correlated with differences in food habits.

WESTWARD EXPANSION OF THE TAWNY-BELLIED COTTON RAT (SIGMODON FULVIVENTER) IN WEST-CENTRAL NEW MEXICO

Abstract In New Mexico, the tawny-bellied cotton rat (Sigmodon fulviventer) previously was known only from central and southwestern parts of the state. In central New Mexico, most records were from areas of tall grass and marshes associated with the middle Rio Grande valley. In 2003, we discovered S. fulviventer in grassy and marshy habitats >100 km west of the Rio Grande in west-central New Mexico. Because past surveys in this region did not report captures of Sigmodon, we suspect our distributional records represent recent westward expansion of S. fulviventer in the state.

First record of the Arizona cotton rat (Sigmodon arizonae) in New Mexico

traron y se fotografiaron los restos de un armadillo de nueve bandas (Dasypus novemcinctus) en el condado Macon en Illinois, USA. Es el registro m~as al norte al este del rio Mississippi, y la primera entrada en las Grandes Planicies de Illinois central. Este registro evidencia la expansi6n al norte del rango de esta especie en Norte America. Este ejemplar se considera como pionero en la expansi6n del rango de esta especie favorecida por los inviernos templados de los filtimos afios. La frecuencia de tales pioneros quizais aumentara a consecuencia del calentamiento global.

Taxonomic assessment of the black bear (Ursus americanus) in the eastern United States

Results showed skulls of U. a. luteolus, U. a. floridanus, and U. a. americanus to be similar in morphology. However, features of U. a. luteolus, and U. a. floridanus tended, in general, to be larger and shaped differently than those of U. a. americanus. Differences between measurements of U. a. luteolus and U. a. floridanus were less apparent than those between either of these taxa and U. a. americanus. For U. a. luteolus and U. a. floridanus, means of most characters differed only slightly, and ranges of all measurements overlapped to some degree. Yet, small numbers of characters that reflected molar tooth measurements or features relating to dentition, height of frontal region, and skull length and width appeared to correctly classify these taxa in most cases. Results were interpreted to support the subspecific recognition of U. a. luteolus, U. a. floridanus, and U. a. americanus. RESUMEN-Con base en caricteres morfol6gicos se evalu6 el estatus subespecifico del oso negro de Louisiana (Ursus americanus luteolus) y del oso negro de Florida ( U. a. floridanus) con la finalidad de determinar las diferencias entre ellos y con el oso negro (U. a. americanus). Se consideraron 44 caricteres craneales de 125 machos y 127 hembras, todos ellos adultos (4.5 afios de edad o mais). Los resultados muestran que los crineos de U. a. luteolus, U. a. floridanus y U. a. americanus comparten similitudes morfol6gicas. Sin embargo, las caracteristicas craneales de U. a. luteolus y U. a. floridanus tendieron a ser mais largas y de forma diferente que las de U. a. americanus. Las diferencias entre las medidas de U. a. luteolus y U. a. floridanus fueron menos aparentes que las que se encontraron entre estos taxa y U. a. americanus. Para U. a. luteolus y U. a. floridanus, los promedios de la mayoria de los carfcteres difirieron ligeramente, y los rangos de todas las medidas se sobrepusieron en algfin grado. Sin embargo, los cardicteres que permitieron clasificar a estos taxa correctamente en la mayoria de los casos fueron: las medidas de los molares, los caricteres relacionados con la dentici6n, la altura de la regi6n frontal, y la longitud y anchura del crfneo. Los resultados se interpretaron para apoyar el reconocimiento subespecifico de U. a. luteolus, U. a. floridanus y U. a. americanus.