Accurate measures of fitness are important for both basic research on sexual selection and applied conservation actions to promote genetic diversity. For polygynous mammals, good estimates of male reproductive success are often critically important, but especially difficult to obtain. Because the genetic contribution of males is impossible to directly measure in the field, investigators have developed surrogate measures of fitness based on behavioral observations. Such measures are founded on the assumption that observed mating success can reliably predict reproductive success, yet only a few studies have been in a position to validate the accuracy of this assumption. We studied the bison herd at Fort Niobrara National Wildlife Refuge for 8 years, conducting intensive behavioral observations on breeding behavior during the rut (2003–2009) and collecting tissue samples of calves born the following year (2004–2010) for genetic paternity analysis. Our results reveal 2 major trends also observed in other studies: Estimates of mating success were positively correlated with reproductive success when we pooled the entire herd across age classes or years. However, copulatory success did a poor job of predicting the actual number of offspring sired by individual males. For example, 44% of observed matings did not result in the birth of offspring, and 60% of the copulations that did produce a calf did not accurately predict the sire bull. Generalized linear mixed model analysis revealed that observation of mating by a given bull in itself had no predictive power regarding likelihood of paternity, whereas total copulations per season, dominance status, and age of bull or dam significantly influenced the probability of siring offspring. Although use of behavioral data was unable to predict the sire for particular cows, it did give insights into patterns of reproductive success that use of genetic data alone could not provide, such as the role of alternate mating strategies and sperm competition for male reproductive success. We conclude that both behavioral and genetic measures of fitness are needed to understand sexual selection and meet the challenges faced by species of conservation concern.

Current paradigms of ungulate population ecology recognize that density-dependent and independent mechanisms are not always mutually exclusive. Long-term data sets are necessary to assess the relative strength of each mechanism, especially when populations display irruptive dynamics. Using an 18-year time series of population abundances of Roosevelt elk (Cervus elaphus roosevelti) inhabiting Redwood National Park in northwestern California we assessed the influence of population size and climatic variation on elk recruitment and whether irruptive dynamics occurred. An information-theoretic model selection analysis indicated that abundance lagged 2 years and neither climatic factors nor a mix of abundance and climatic factors influenced elk recruitment. However, density-dependent recruitment differed between when the population was declining and when the population increased and then stabilized at an abundance lower than at the start of the decline. The population displayed irruptive dynamics.

Differences in resource selection (i.e., habitat selection and diet composition) may allow for coexistence of interspecific competitors. Two congeneric floodplain antelope with broadly similar habitat use are puku (Kobus vardonii) and lechwe (K. leche). In Botswana, puku are restricted to a narrow band of floodplains along the Chobe River, whereas lechwe are far more abundant, with a distribution encompassing the Chobe Riverfront, the Linyanti Swamps, Kwando River, and the Okavango Delta. We investigated factors to try to explain the contrasting distribution patterns of puku and lechwe, including seasonal diet composition and overlap, seasonal nutritional status as indicated by fecal nitrogen and phosphorus, and habitat selection. Dietary overlap ranged from 84% to 90% across seasons. Cynodon dactylon was the greatest contributor to the diets of both puku and lechwe, but there were differences in the relative contributions of particular grass species associated with uplands or floodplains. Fecal nitrogen and phosphorus did not differ between species and did not indicate nutritional deficiencies for either puku or lechwe. Habitat selection was broadly similar during the low-water season, but during the high-water season, puku moved from the floodplain into shrublands habitats, whereas lechwe remained on the floodplains. We hypothesize that increased predation risk during the high-water season, due to increased visual obstruction in shrublands, may limit abundance of puku in the study area.

In view of contradictions in the recent literature, the valid genus-group name to be applied to northern red-backed voles—Myodes Pallas, 1811, or Clethrionomys Tilesius, 1850—is reviewed. To develop the thesis that Myodes (type species, Mus rutilus Pallas, 1779) is the correct name, our discussion explores the 19th-century taxonomic works that bear on the relevant taxa, the transition in zoological codes apropos the identification of type species, and past nomenclatural habits in cases where no type species was originally indicated. We conclude that Myodes is the senior name to use for the genus-group taxon that includes the Holarctic species rutilus and frame this conclusion within a synonymy of the genus.

Although temporal partitioning has long been viewed as a valid mechanism in reducing competition, direct field evidence is rare, and the temporal niche is often considered less important than other factors in promoting coexistence. Furthermore, the relative importance of biotic and abiotic factors in shaping diel activity patterns of animals is poorly understood. We conducted controlled experiments in a little-studied area (Hulunbuir meadow steppe, China) to explore the effects of presence of a larger species, Spermophilus dauricus, and ambient temperature in shaping diel activity patterns of Microtus gregalis. Our results suggest that although interference competition existed between S. dauricus and M. gregalis, the presence of S. dauricus did not significantly affect the diel activity patterns of M. gregalis (P > 0.05). Timing of activity of M. gregalis, however, was always significantly correlated with ambient temperature (P < 0.001). As winter approached, ambient temperature appeared to be a major factor in shaping activity patterns of M. gregalis. To our knowledge, this is the 1st experimental study conducted in an East Asian steppe to integrate the roles of both biotic and abiotic factors in shaping rodent activity patterns.

Multiple ecological factors are known to drive variation in social behavior. However, group-living in some species appears to be highly conserved, suggesting a phylogenetic influence. In this study, we evaluated both scenarios using intraspecific and interspecific comparisons across octodontid rodents. We first examined 2 different populations of Andean degu (Octodontomys gliroides), representing 2 extremes of a climate vegetation gradient across the Andes range. We evaluated how ecological variation in terms of abundance and distribution of food resources, predation risk, and burrowing costs predicted interpopulation variation in group size and range-area overlap (2 proxies of sociality). We estimated these measures of sociality from livetrapping and radiotelemetry. We then used phylogenetic methods to determine whether sociality exhibits a phylogenetic signal and reconstructed the ancestral state of sociality across the family Octodontidae. Overall activity of females and males of O. gliroides was greater during nighttime than daytime. Across populations we found significant differences in ecology, including abundance and distribution of food, predation risk, and burrowing costs. However, populations were similar in terms of group size and range-area overlap. The phylogenetic approach revealed a strong and significant phylogenetic signal associated with sociality, where this behavior was present early during the evolution of octodontid rodents. Together, these findings imply that sociality of O. gliroides is not linked to current population differences in ecology.

La variación en la conducta social ha sido atribuida a múltiples factores ecológicos. Sin embargo, la vida en grupo en algunas especies es un rasgo altamente conservado, sugiriendo una influencia filogenética. En este estudio, se evaluó ambos escenarios usando comparaciones intraespecíficas e interespecíficas a través de roedores octodóntidos. En primer lugar se evaluaron 2 poblaciones de degu Andino (Octodontomys gliroides) que representan 2 extremos de un gradiente climático y de vegetación a través de la Cordillera de los Andes. Se evaluó como la variación en términos de abundancia y distribución de recursos alimenticios, riesgo de depredación, y costos asociados a cavar madrigueras podrían predecir la variación interpoblacional en tamaño de grupo y solapamiento del ámbito de hogar (2 medidas de sociabilidad). Estas medidas fueron estimadas con datos de trampeo y radiotelemetría. Además, se utilizaron métodos filogenéticos para determinar si el rasgo social presenta señal filogenética, y de esta manera reconstruir el estado ancestral de la sociabilidad a través de la familia Octodontidae. Se encontraron diferencias estadísticamente significativas entre las poblaciones en términos de ecología, incluyendo abundancia y distribución de recursos alimenticios, riesgo de depredación, costos asociados a cavar madrigueras. Sin embargo, el tamaño de grupo y solapamiento del ámbito de hogar fueron similares entre ambas poblaciones. El análisis filogenético reveló una fuerte y significativa señal filogenética asociada a la sociabilidad, y que esta conducta estuvo presente temprano en la evolución de los roedores octodóntidos. En conjunto, estos resultados implican que la vida en grupo en O. gliroides no está relacionada a las diferencias en ecología en las poblaciones actuales.

Natal dispersal, the process of moving between the natal site and the site of 1st reproduction, affects a variety of ecological and evolutionary processes. Multiple factors have been suggested to influence patterns of natal dispersal in vertebrates; sex and population density are 2 of the most frequently invoked. In mammals, males are typically expected to disperse farther or more frequently than females. In contrast, theoretical predictions about the effect of population density are less clear, and support exists for both positive and negative density-dependent dispersal. Here, I investigate the influences of sex and population density on dispersal distances and spatial genetic structure (SGS) in the brush mouse (Peromyscus boylii), using both intensive field surveys and spatial genetic autocorrelation methods. Neither density nor sex affected dispersal distances. I did detect increased genetic structure in females compared to males, a pattern consistent with male-biased dispersal. However, processes other than dispersal can generate SGS, and I suggest that in addition to sex-biased dispersal, these results also could reflect gene dispersal via mating excursions. No clear effect of population density on either dispersal distance or SGS emerged. These results highlight the importance of using multiple methodologies to investigate dispersal.

Dispersión natal, el proceso de traslado entre el sitio de nacimiento y el sitio de la primera reproducción, afecta una variedad de procesos ecológicos y evolutivos. Se han sugerido múltiples factores que pueden influenciar los patrones de dispersión natal en vertebrados; el sexo y la densidad de la población son los 2 factores más frecuentemente invocados. En los mamíferos, típicamente se espera que los machos se dispersen más lejos y más frecuentemente que las hembras. En contraste, las predicciones teóricas acerca del efecto de la densidad poblacional no son tan claras, y existe apoyo para ambas formas de dispersión dependiente de la densidad, positiva y negativa. Aquí, investigo la influencia del sexo y la densidad poblacional en las distancias de dispersión y la estructura genética espacial en el ratón de maleza (Peromyscus boylii), usando estudios de campo intensivos y métodos de auto correlación genética. Ni la densidad ni el sexo afectaron la distancia de dispersión. Detecté una elevada estructura genética de las hembras comparada con la de los machos, un patrón consistente con la expectación típica de la dispersión masculina. Sin embargo, procesos diferentes a la dispersión pueden generar estructura genética espacial, y yo sugiero que además a la dispersión sesgada por sexo, los resultados también pueden reflejar dispersión de genes a través de excursiones de apareamiento. No se apreciaron efectos de la densidad poblacional en la distancia de dispersión o en la estructura genética espacial. Estos resultados demuestran la importancia del uso de múltiples métodos para investigación la dispersión.

In many mammals, juveniles are vulnerable to predators because of their low mobility and small body size. Cover hides juveniles from predators and has been assumed to lower predation risk. However, among mammal species, studies relating use of cover to fitness remain infrequent and have been predominantly performed on ungulates. We measured habitat selection and survival of juvenile North American porcupines (Erethizon dorsatum). We tested whether juveniles selected for cover, use of cover depended on meteorological conditions (there could be a trade-off between predation risk and radiative heat gain during sunny days), and use of cover influenced survival. We also examined how sex, body mass, mobility of the juvenile, and distance to the mother affected survival. We found that juvenile porcupines (14 individuals observed on 299 occasions) selected high protective cover (microhabitat scale) within areas with low herb cover (local scale). Use of cover partly depended on weather, with use of dens decreasing on sunny and warm days but use of cover outside of the den being independent of meteorological conditions. Ten juveniles died during the study and 90% of deaths were due to predation. Use of microhabitats with high protective cover and use of sites with high shrub cover at the local scale enhanced survival. We found no effect on survival of sex, body mass, mobility, and distance to the mother. These results demonstrate that use of cover was crucial to survival in a system where predation was the main limiting factor, and that predation risk was modulated by habitat use of juveniles.

Intraspecific variability in echolocation calls could be an important factor hampering the accurate acoustic identification of species in the field. We studied variations in the echolocation behavior of Lasiurus varius in relation to habitat structure. Echolocation calls of L. varius reflected the degree of clutter present in its foraging areas. Bats foraging in an uncluttered habitat emitted longer and lower-bandwidth calls, with the lowest frequency values, whereas bats foraging in a cluttered habitat broadcast shorter and broadband signals, showing an increase in frequency content of their calls. Discriminant function analysis gave an overall classification of 76% of the calls emitted in the different flight situations. Our results highlight the need for independent recordings at each study area or habitat type to circumvent potential echolocation call variations, particularly in fragmented landscapes.

Loss of roost sites in buildings represents the major threat to Myotis myotis populations in the Czech Republic. To identify features that may determine roost selection by M. myotis, we compared a range of structural and habitat variables for 17 maternity roosts and 17 unoccupied, but potentially suitable, buildings in the Moravian Karst (Czech Republic). Roosts and control sites were mainly in churches and chateaus and all were detached from the surrounding buildings and uninsulated. The only difference between habitat surrounding roost and control buildings was that roost buildings had relatively lower amounts of hedges as linear connective features. Our results suggest that bats do not select building features from among suitable detached and uninsulated churches and chateaus and that bats tend to select building roosts that are not connected to woodland by hedges. Protection of roosts is an important conservation issue for female M. myotis and suitable roost sites such as detached and uninsulated buildings that are not connected to woodland by hedges are important maternity roosting resources.

Bats play an important role in regulating ecosystems, and seasonality has great influence on their reproductive cycle and storage status of bodily energy reserves. Aiming at a better understanding of the dynamics of these processes, male little yellow-shouldered bats (Sturnira lilium) were captured during both the dry and rainy seasons and their reproductive and metabolic patterns were established. Testes were processed histologically for morphometric analysis by light microscopy. Plasma glucose and testosterone concentrations were determined, as well as liver and muscle glycogen, lipids, and protein. Data showed little variation in testicular morphometrical parameters and also in body energy reserves between the seasons evaluated. We conclude that occasional season variations in bodily energy reserves in S. lilium do not seem to present a major influence on testicular morphometry in this species, which may reflect a successful adaptation of S. lilium to its habitats.

The understanding of the spatial structure and dynamics of populations can guide conservation decisions, but studies of this type focused on small (< 7-kg) carnivores are rare. We compared survival, reproduction, and dispersal of radiocollared Geoffroy's cats (Leopardus geoffroyi) in a protected area and adjacent cattle ranches in Argentina to assess the effects of livestock management and its associated disturbances (i.e., hunting by humans) on the demography of this felid. Thirteen cats in the park and 13 in the ranches were radiotracked for up to 556 days in 2007–2008. We evaluated the Geoffroy's cat population trajectory at the landscape level using a stage-structured, stochastic matrix model based on our estimated vital rates. The study occurred during a prolonged drought, likely affecting estimated vital rates. Survival in the ranches was 52% lower than in the park; mortalities were due to intraguild predation in the park and were human-related in the ranches. Dispersal from the ranches was 32% lower than from the park and dispersal distances were up to 128 km. The number of cubs per litter was similar between areas. Assuming persistence of drought conditions and estimated vital rates, the simulated metapopulation rapidly collapsed and cat survival on ranches was the vital rate to which the model was most sensitive. Because projected climatic scenarios predict increased drought frequency for the region, we explored management options that would enhance chances of persistence, simulating 2 “adaptation” strategies: hunting restrictions on ranches and expanding protected areas. More than doubling of cat survival on ranches or a 9-fold increase in protected area extension would be required, involving major investments, to avoid the extinction of this cat metapopulation if droughts become prevalent. Our analysis may be helpful to improve our predictive capacity to identify new threats and facilitate adaptation strategies for Geoffroy's cat or other similar carnivores.

La comprensión de la estructura espacial y la dinámica de las poblaciones pueden guiar decisiones de conservación, pero los estudios de este tipo centrados en pequeños carnívoros (< 7 kg) son raros. Se comparó la supervivencia, reproducción y dispersión de gatos monteses (Leopardus geoffroyi) equipados con radiocollar en una zona protegida y campos ganaderos adyacentes en Argentina, para evaluar los efectos del manejo ganadero y sus disturbios asociados (p.e., la cacería) sobre la demografía de este felino. Trece gatos en el parque y 13 en los campos fueron monitoreados por hasta 556 días durante 2007–2008. Se simuló la trayectoria de la población monitoreada a nivel del paisaje utilizando un modelo matricial estocástico estructurado por edades, basado en las tasas vitales estimadas. El estudio tuvo lugar durante una sequía prolongada, lo que probablemente afectó las tasas vitales estimadas. La supervivencia de los gatos en los campos fue 52% menor que en el parque; la mortalidad se debió a depredación intragremio en el parque y estuvo mayormente relacionada al hombre en los campos. La dispersión desde los campos fue 32% menor que desde el parque y las distancias de dispersión fueron de hasta 128 km. El número de crías por camada fue similar entre áreas. Asumiendo la persistencia de la sequía prolongada y las tasas vitales estimadas, la metapoblación simulada declinó rápidamente, siendo la supervivencia de los gatos en los campos la tasa vital más sensible para el modelo. Dado que los escenarios climáticos proyectados predicen una mayor frecuencia de sequías para la región, se exploraron opciones de manejo para mejorar las posibilidades de persistencia de esta población, simulando dos “estrategias de adaptación”: restricciones de cacería en los campos y ampliación del área protegida en el paisaje estudiado. Para evitar la extinci

We collected and analyzed data on the annual course of reproduction of the Egyptian fruit bat (Rousettus aegyptiacus) in 2 climatically distinct areas, the Mediterranean and the Egyptian desert, located at the northern limits of the species' distribution. In both regions, reproductive seasonality was characterized by distinct bimodality in birth timing regardless of climatic differences. A low incidence of simultaneous pregnancy and lactation indicated that both seasonal bimodal polyestry with and without postpartum estrus may occur in both regions, with a possibly lower incidence of postpartum estrus in females from the Mediterranean population. Observed shifts in birth timing between the Mediterranean and the desert study area corresponded to regional differences in fruiting phenology of major dietary plants. The male reproductive cycle was synchronized with that of females. The period of testicular recrudescence occurred during the peak pregnancy period. Because testis size was related to body mass irrespective of body size, we hypothesize that food abundance is an important trigger of male sexual activity. R. aegyptiacus is the sole species with seasonal bimodal polyestry among Palearctic bats.

Sika deer (Cervus nippon) in the Japanese archipelago are cervids known to have high ecological plasticity, which is reflected in latitudinal variation in their feeding habits. The northern populations are grazers that depend on dwarf bamboos, whereas the southern ones feed on browse and fruits. These differences in plant composition of the diet should affect the tooth wear patterns because the different plants have different concentrations and morphologies of phytoliths (microscopic silica bodies that precipitate in and around cells in many plants). We studied 2 mainland populations (Mt. Goyo and Oshika Peninsula) and 1 island population (Kinkazan Island) of sika deer from northern Japan to understand how dwarf bamboo (Sasa nipponica and Sasamorpha borealis) affects tooth wear on the mainland populations in comparison to the lawn grass (Zoysia japonica) consumed by the island population. Fruits are not considered in this study because only northern populations are examined. The combined analyzes of tooth mesowear and microwear permitted us to detect seasonal differences in the feeding habits of sika deer. The tooth wear pattern also reflected differences directly related to the type of plant ingested. The grass Zoysia japonica, available on Kinkazan Island, had a highly abrasive effect on sika deer enamel. The bamboo species S. nipponica and S. borealis, more abundant on the Mt. Goyo and Oshika Peninsula areas, respectively, were less abrasive than Z. japonica. Differences also were detected in the wear patterns produced by the 2 species of bamboo. Tooth mesowear suggests that S. nipponica is more abrasive than S. borealis, which was confirmed by the high phytolith content found in the plant, especially in the stem of S. nipponica, the part consumed by the sika deer in late winter.

Itjaritjari, the southern marsupial mole (Notoryctes typhlops), is an extreme fossorial species that is very rarely encountered on the surface and has been regarded as a sand swimmer that leaves no reliable trace of its passage through the sand. Like many extreme fossorial species on other continents, itjaritjari is poorly known and is considered rare and threatened. In this study, surface tracks known to have been made by itjaritjari were followed underground where they became clearly defined, circular, sand-filled tunnels with a mean diameter of 39 mm. Trenches dug to expose vertical sections of dune revealed that backfilled tunnels of similar appearance and dimensions were common on dunes in the study areas, averaging 3.2 backfilled tunnels per vertical square meter. Loose sand, and thus opportunities for sand swimming, is confined to the surface in the Australian dune fields, which are well vegetated and characterized by lightly bonded sand. Rather than sand swim, itjaritjari carves tunnels and backfills as it goes, leaving clearly distinguishable and unique traces of its passage (“moleholes”) that accumulate over years or decades. This finding provides a much needed means of investigating the distribution, abundance, and conservation of marsupial moles. The technique may have application in the study of several other elusive fossorial species on other continents that may backfill their tunnels, many of which are endangered.

Humpback whales (Megaptera novaeangliae) from a breeding ground off Gabon (0–4°S) and a migratory corridor/feeding ground on the west coast of South Africa (WSA; 33°S) differ genetically and in catch histories. Interpretation of the population structure is hampered by the lack of data from the intervening 3,500 km of coastline or to the north of Gabon. Here we collate all relevant nongenetic data on humpback whales from Namibia (∼23°S) from 2005 to 2012 and compare these with corresponding data from Gabon (2000–2006) and WSA (1983–2008). Data from Namibia include photographic catalogs of dorsal fin and tail fluke images, seasonal presence, and a photographic assessment of scarring and wounds from cookiecutter sharks (Isistius sp.). No confirmed photographic identification matches could be made between Namibia and Gabon and only 2 potential matches were made between Namibia and WSA from dorsal fins. Humpback whales in Namibia show a bimodal seasonality in occurrence, with a primary peak in austral winter (July) and a secondary peak in spring (September), but generally low directionality of movement. Whales were never recorded to sing, competitive groups were rarely sighted, and very few calves were observed, making it unlikely that this is a breeding area. The prevalence of killer whale bite scars on flukes was similar at all sites. Fresh bites from cookiecutter sharks were highest in Namibia, intermediate in Gabon, but almost nonexistent in WSA. We propose that animals seen in Namibia in winter are on their northward migration and have intercepted the coast from farther offshore (where cookiecutter sharks occur), whereas animals seen in WSA in spring–summer, where they are feeding during their southward migration, have followed a slow coastwise route within the cold Benguela Ecosystem, thus allowing time for cookiecutter bites to heal.

Foresman, K. R. 2012. Mammals of Montana. Montana Press Publishing Company, Missoula, Montana, 430 pp. ISBN 978-0-87842-590-7, price (paper), $32.

Seabloom, R. with contributions by J. Hoganson and W. Jensen. 2011. Mammals of North Dakota. North Dakota Institute for Regional Studies, Fargo, North Dakota, 461 pp. ISBN 978-0-911042-74-0, price (paperback), $36.00.