Abstract. Prior to the mid 1850s armadillo dispersal may have been inhibited by native subsistence hunters, the Rio Grande acting as a physical hindrance, and natural habitat barriers posed by fire‐maintained grasslands. European colonists settled south Texas in mass during the latter half of the 19th century and largely removed existing impediments to armadillo range expansion, effectively releasing the species into the United States. The speed of the armadillo's natural range expansion after 1850 was probably accelerated by human travel and commerce into and out of its historic range in south Texas on a proliferation of roadways and railroads. This translocation process will likely continue and, combined with natural dispersal, will provide the armadillo the opportunity to ultimately become established in any habitats in the United States in which it can survive. Limits to future distribution will likely be determined by climatic factors, and may be bounded by regions receiving at least 38 cm annual precipitation and having mean January temperatures >−2°C, or fewer than 24 total annual freeze days. Armadillos may have already approached a precipitation‐defined boundary to the west and a distribution on the Great Plains limited by winter temperature minima. They may be expected to continue their advance up the East Coast to about the region of 41° North Latitude, decreasing to 39° North Latitude across the midwestern states. Future introductions on the West Coast may result in the establishment of armadillo populations in suitable habitats from California to Washington, an event that has already taken place with another tropical mammal emigrant, the opossum.

Ultrasonic detectors are widely used to survey bats in ecological studies. To evaluate efficacy of acoustic identification, we compiled a library of search phase calls from across the eastern United States using the Anabat system. The call library included 1,846 call sequences of 12 species recorded from 14 states. We determined accuracy rates using 3 parametric and 4 nonparametric classification functions for acoustic identification. The 2 most flexible classification functions also were the most accurate: neural networks (overall classification accuracy = 0.94) and mixture discriminant analysis incorporating an adaptive regression model (overall classification accuracy = 0.93). Flexible nonparametric methods offer substantial benefits when discriminating among closely related species and may preclude the need to group species with similar calls. We demonstrate that quantitative methods provide an effective technique to acoustically identify bats in the eastern United States with known accuracy rates. © 2011 The Wildlife Society.

Eastern red bats (Lasiurus borealis) have been found to overwinter in areas that can experience severe fluctuations in temperature. We examined the red bat's use of winter roosts in southwest Missouri, USA, for 2 winters (2003–2005). We found tree roosts in eastern red cedars (Juniperus virginiana) and hardwoods. Tree roost sites were located on the south side of trees, and we found roost trees on south‐facing slopes. Roost sites occurred more frequently in the location with least canopy cover. Bats switched from tree roosts to leaf litter roosts when ambient temperatures approached or fell below freezing. We found habitat characteristics and aspect to be determining factors in the selection of leaflitter roosts. Management of overwintering red bats requires a diverse forest structure, including canopy gaps, stand‐density variation, and leaf‐bearing trees, including oaks (Quercus spp.).

We conducted a new survey of biologists throughout the southern and central United States, in order to update our last analysis of the range expansion and distributional limits of the nine‐banded armadillo (Dasypus novemcinctus) since 1994. While the armadillo's range has remained stationary to the west along a line corresponding to about 50 cm annual precipitation, it has advanced to the north through central Kansas, into central Illinois, south‐western Indiana and western Kentucky, through central Tennessee, covering Alabama and all but the north‐eastern region of Georgia, and into central South Carolina. The population has reached a latitude corresponding to an average minimum daily January temperature of −8 °C in Kansas. Armadillos may continue to move northwards in states farther east where they do not yet reach the −8 °C zone. In the eastern seaboard states, other factors besides winter temperature extremes may be limiting the armadillo's range expansion.

G- and C-banded karyotypes from 9 previously unstudied species of Peromyscus are described and compared to the 9 species described in the literature. Additional new data are presented for P. eremicus. A hypothetical evolutionary tree for the 18 species was constructed based on the assumption that, where possible, shared chromosomal rearrangements became established in a common ancestor. A minimum of 60 chromosomal rearrangements (34 heterochromatic additions and 26 pericentric inversions) were needed to construct the most parsimonious tree. Seven of the 18 species have heterochromatin in noncentromeric areas. Three times as many inversions have been identified in the 11 largest pairs as have been observed in the 12 smallest pairs. Peromyscine rodents are characterized by a pattern of chromosomal variation quite distinct from that described for other rodent genera, such as Sigmodon and Mus. Karyotypic orthoselection in rodents appears to be relatively common in closely related species.