Bats of Texas

Chapter 11: Then and Now

146 family vespertilionidae uropatagium. The species name refers to the Native American Indian tribe, the Seminoles, that historically occupied the region of Florida where the type specimen was collected (Stangl et al. 1993). Lasiurus seminolus (Rhoads, 1895) Seminole Bat Etymology. The generic name, Lasiurus, comes from the Greek words lasios, meaning “shaggy,” and oura, meaning “tail,” which refers to the well-furred Seminole bat (Lasiurus seminolus) seminole bat 147 Gulf Coastal Plains, East Central Great Plains, Blackland Prairies, Cross Timbers ) until it was recently documented on the western edge of the Edwards Plateau as well (Brant and Dowler 2000). It is most commonly encountered in the pine-oak forests of eastern Texas. The species is a year-round resident of Texas, although winter records are rare, and none exist for the months of November and December. Life History. For many years, it was thought that Seminole bats preferred roosting in clumps of Spanish moss. However, few bats actually were ever found in Spanish moss, and those were captured in the winter (Carter and Menzel 2007). Recently, several radiotelemetry studies have found that these bats most frequently roost in clumps of needles on small branches of pine trees, particularly slash and loblolly pine. Roosts in the foliage of pines constitute 85–95% of the roosting sites of this species in the summer in South Carolina, Subspecies. Lasiurus seminolus (Rhoads, 1895) is a monotypic species, and no subspecies are recognized. Description. This is a medium-sized bat (forearm = 35–45 mm) with short, rounded ears. As with other bats of the genus Lasiurus, the interfemoral membrane is densely furred dorsally. The pelage is a dark reddish brown (or mahogany ), and the hair tips are sometimes white, giving the fur a frosted appearance . Lasiurus seminolus may be confused with the eastern red bat (Lasiurus borealis), from which it is distinguished as described in the account of the latter. Dental formula: I 1/3, C 1/1, Pm 2/2, M 3/3 × 2 = 32. Average external measurements are as follows: total length, 103 mm; tail, 44 mm; hind foot, 8 mm; ear, 12 mm; forearm, 39 mm. Weight: 9–14 g. Distribution. This bat is distributed across the southeastern United States, and in Texas it had been known from 5 physiographic regions (South Central Plains, Specimen record Literature record DSHS record map 14. Distribution of the Seminole bat, Lasiurus seminolus. 148 family vespertilionidae to reduce its activity when ambient temperatures reach 21°C (70° F; Constantine 1958d), and generally they do not fly at temperatures below 18°C (64° F; Jennings 1958). In South Carolina, when temperatures fall below freezing, roosts are typically found beneath leaf litter on the forest floor. At temperatures between 0 and 4°C (32–39°F), they select roost sites in pine needle clusters < 5 m above the ground. Roosting at lower heights in cold weather likely provides protection from the wind (Hein et al. 2008a). Although migratory movements have been documented for several tree bat species, the evidence of Seminole bat migration is largely circumstantial. Many of the extralimital records of Seminole bats are from the autumn, when young bats presumably are wandering (Wilkins 1987). For example, an adult female was captured outside a mineshaft in Arkansas in September (Heath et al. 1983); records from New York (Layne 1955) and Pennsylvania (Poole 1932, 1949) were in the autumn, and the single record of L. seminolus from West Texas was also in September (Brant and Dowler 2000). Specimens have been collected in East Texas from February through November (Schmidly et al. 1977). Seasonal differences in the distribution of males and females have been documented. For example, in South Carolina, females outnumber males nearly 2:1 in the summer, but no females have been captured from January to March (Hein et al. 2008a, 2008b). In the summer, the ratio of females to males is even more highly skewed Georgia, and Arkansas. Mature stands of pines are preferred roosting habitat, and trees used as roosts are taller and larger in diameter than the surrounding trees (Hein et al. 2008b; Menzel et al. 1998, 1999, 2000; Perry and Thill 2007d; Perry et al. 2007b). When roosting among pine needles, these bats hang motionless and appear to be a pine cone. During the winter, they use a wider variety of roosting sites, including Spanish moss, the canopy of overstory trees, hanging vines, shrubs, and leaf litter on the forest floor. Supposedly, these winter roosting substrates provide insulation against cold winter temperatures (Constantine 1958d; Hein et al. 2005, 2008a; Hutchinson and Meisenburg 2004). Roosts typically are occupied by a single individual or a female with young. The height of roosts ranges from 1 to 19 m above the ground (Constantine 1958d; Menzel et al. 1999, 2000). These bats change roosts frequently and rarely use the same one for more than 1–2 days but tend to stay in the same general area (Hein et al. 2008b; Menzel et al. 1998). The mean size of the roosting home range is from 0.2 hectares in Georgia to 5.85 hectares in South Carolina, and reproductive females have the largest roosting home range size (Hein et al. 2008b; Krishon et al. 1997). Roosting home range sizes are substantially larger in winter than in summer, although roost switching is less frequent during colder weather, when bats may occupy the same roost for up to 12 consecutive days (Hein et al. 2005, 2008a). The Seminole bat is thought to remain active throughout the year, although it begins western yellow bat 149 mature quickly and are able to fly at 3–4 weeks of age. Young bats tend to wander far from their natal roost after they have been weaned. Out of a total of 200 Seminole bats submitted to the DSHS from 1984 to 1987 and 1996 to 2000, 19 (9.5%) tested positive for the rabies virus. Status. The IUCN 2011 status of the Seminole bat is “least concern.” This species is locally abundant throughout eastern Texas and may be expanding its range westward. Specimens Examined. Go to www.batsof texas.com for more detailed information about the total of 129 specimen records of L. seminolus from Texas. Additional records: Cass County (1) (McAllister et al. 2004), Harrison County (1) (Yancey and Jones 1996b), Travis County (1-TTU76878). References. 33, 59, 86, 98, 101, 106, 116, 136, 180, 212, 214, 215, 225, 268, 336, 511, 524, 532, 533, 534, 535, 608, 618, 661, 676, 702, 732, 734, 760, 767, 770, 780, 781, 799, 801, 803, 817, 833, 919, 923, 951, 952, 970, 1017, 1025, 1026, 1028, 1030, 1044, 1091, 1164, 1250 Lasiurus xanthinus Thomas, 1897 Western Yellow Bat Etymology. The generic name, Lasiurus, comes from the Greek words lasios, meaning “shaggy,” and oura, meaning “tail,” which refers to the well-furred uropatagium. The specific name comes from the Greek word xanthos, for “pertaining to yellow” (Stangl et al. 1993). Subspecies. Lasiurus xanthinus Thomas, 1897, is monotypic, and no subspecies are recognized. toward females in Mississippi, where they outnumber males 5:1 (Miller 2003). Seminole bats feed early in the evening over watercourses and clearings , generally at treetop level. Their flight is swift and direct, and they may occasionally alight on vegetation to capture prey (Marks and Marks 2006). In North Carolina, they forage primarily in pine stands (55% of the time) but also use bottomland (35%) and upland hardwood habitats (11%; Carter et al. 2004). Foraging area was found to range from 79.2 hectares for a lactating female to 289.6 hectares for a juvenile female in Georgia. The foraging area was located in a pine stand that was spatially discrete from the roosting area (Krishon et al. 1997). In Georgia, 95% of the diet of Seminole bats comprises beetles, flying ants, and moths (Carter et al. 1998). Additional prey items include true bugs, flies, and even ground-dwelling crickets (Carter et al. 2004; Wilkins 1987). In urban areas, Seminole bats are known to frequent streetlights to feed on insects attracted to the light. Seminole bats are known to mate in the fall; reproductively active males have been documented in February and April in Georgia, so mating likely occurs in the spring as well (Constantine 1958d). Females may carry from 1 to 4 embryos but usually give birth to 2 young (Davis 1974). Pregnant females have been taken in May and June (Wilkins 1987). In Texas, parturition occurs in late May or June. Lactating females have been documented in the Big Thicket of Texas in late June and in Mississippi in mid-July (Miller 2003). The young bats 150 family vespertilionidae mask. The northern yellow bat (L. intermedius ) and L. xanthinus are similar in color, but the former is larger (forearm usually greater than 47 mm) and does not occur in the same areas where one would expect to find L. xanthinus. Distribution. Lasiurus xanthinus occurs in arid regions of the southwestern United States, along the Mexican Plateau west of the Sierra Madre, and Baja California. It was first documented in Brewster County, Texas, in October 1996 (Higginbotham et al. 1999). It has since been reported from other sites in the Chihuahuan Desert region as far east as Val Verde County (Bradley et al. 1999; Jones et al. 1999; Weyandt et al. 2001). Most individuals have been captured in autumn in Black Gap Wildlife Management Area and the adjacent Big Bend National Park. However, they have been captured in Texas in March, June, July, Description. This is a medium-sized bat (forearm = 43–47 mm) with pale yellow pelage. Hairs have a dark base. The interfemoral membrane is furred for about half its length, and the hairs here are brighter yellow and contrast with the rest of the pelage. The western yellow bat’s wing membranes are dark, and it lacks a dark face mask. The ears are pinkish brown and have a rounded tip. Dental formula: I 1/3, C 1/1, Pm 1/2, M 3/3 × 2 = 30. Average external measurements are as follows: total length, 105 mm; hind foot, 10 mm; ear, 13.5 mm; forearm, 45 mm. Weight: 12–20 g. The western yellow bat may be confused with its southern relative, the southern yellow bat (L. ega), and identi- fication is very difficult. In L. ega, hairs of the interfemoral membrane do not contrast with the color of hairs on the dorsum, and the bats have a dark face Western yellow bat (Lasiurus xanthinus) western yellow bat 151 the most probable explanation is the warmer temperatures recently recorded in West Texas. Vegetational changes in the region also may have facilitated the northward range expansion of the species. Cottonwood trees (Populus spp.) and other riparian vegetation in the Trans-Pecos region were almost exterminated early in the twentieth century, but the establishment of Big Bend National Park and other protected areas in the region have allowed the recovery of natural vegetation. This woody, riparian growth provides suitable roosting and foraging habitat for L. xanthinus. Western yellow bats have been found using giant dagger yucca (Yucca carnerosana ) as a roost site in Texas (Higginbotham et al. 2000), and Washington fan palms (Washingtonia filifera) are used in Arizona and Nevada (Cockrum 1961; O’Farrell et al. 2004). In both cases, the bats were found roosting among the dead leaves of the petticoat. In addition, L. xanthinus roosts in some deciduous September, October, and November. Outside of Texas (Nevada) they are somewhat active in the winter months (O’Farrell et al. 2004). The presence of lactating females in Jeff Davis and Brewster counties indicates that at least some L. xanthinus raise their young in Texas. Recent captures by Raymond Matlack (pers. comm.) of West Texas A&M University confirm that the species still occurs in the state. Nine individuals (8 males, 1 female) were captured in September 2007 in Black Gap Wildlife Management Area, Brewster County. Furthermore, as recently as 2010 specimens have been documented from El Paso County (Tipps et al. in press). Life History. This species represents a recent addition to the fauna of Texas. All evidence suggests that this is a result of an expansion of the species’ range rather than the absence of previous collecting success. The reasons for such a range expansion are not well understood, but Specimen record Literature record DSHS record map 15. Distribution of the western yellow bat, Lasiurus xanthinus. 152 family vespertilionidae Mexico have taken them “relatively late at night” (Cook 1986). Discrepancies in time of capture could be influenced by several factors, including a late emergence time, foraging before drinking, or commuting long distances between roosting and foraging areas. Based on radiotracking data, 1 individual in Big Bend National Park was captured more than 22 km away from its roost site, which lends some support to the third possible factor (Higginbotham et al. 2000). Information about their diet is scarce. The diet of 1 male from Brewster County comprised true bugs, flies, wasps, moths, beetles, and crickets (Higginbotham et al. 1999). In addition to these food items, leafhoppers also have been documented in their diet in southern Nevada (O’Farrell et al. 2004). Details about reproduction in this species are not well known. Its reproductive biology is probably similar to that of the southern yellow bat (Lasiurus ega), with one notable difference—litter size is typically 2, as opposed to 3–4 as seen in other lasiurines. In New Mexico, pregnant females, all carrying 2 embryos , were captured in May and June; lactating females have been taken in August (Cook 1986; Mumford and Zimmerman 1963). Pregnant females also have been reported from southern California in June (Bond 1970), and lactating females have been captured in Texas in late June (Jones et al. 1999). Juvenile western yellow bats have been captured in July and September in southern Nevada (O’Farrell et al. 2004). Rabies was first reported in this species in 1979 in California, where 8 out of tree species, including hackberry (Celtis spp.), sycamore (Platanus spp.), and cottonwood (Bond 1970; Brown 1996; Findley et al. 1975; Mumford and Zimmerman 1963). Western yellow bats have been found in a wide variety of habitats in the United States at elevations of 550–1,750 m. In Nevada (Moapa Valley), these bats primarily use riparian woodlands dominated by Washingtonia fan palms (O’Farrell et al. 2004; Williams et al. 2006). In Big Bend National Park, Texas, they have been taken in lowland desert riparian zones (850 m) dominated by cottonwood, acacia (Acacia spp.), and willow (Salix spp.; Higginbotham et al. 1999). They have been encountered in the Davis Mountains over a creek at approximately 1,525 m among cottonwood and willow species (Jones et al. 1999). They also have been encountered in riparian areas dominated by sycamore or cottonwood and in woodland habitats with oak or pinyon-juniper vegetation in the Animas Mountains of New Mexico (Cook 1986). Farther south, on the Mexican Plateau, they have been captured in agricultural areas and mesquite /scrub habitat from 700 to 2,350 m (Baker 1956; Genoways and Jones 1968). As one of us (Loren K. Ammerman) has documented, most captures of this species in mist nets in Texas tend to take place later in the evening—at least 1.5 hours after sunset, but more commonly 3–4 hours after sunset. In New Mexico this species was captured somewhat earlier in the evening, from 30 minutes to 2.25 hours after sunset (Mumford et al. 1964), but other researchers in New silver-haired bat 153 575, 628, 767, 841, 850, 852, 880, 1026, 1028, 1091, 1124, 1190, 1224 Lasionycteris noctivagans Le Conte, 1831 Silver-Haired Bat Etymology. The generic name, Lasionycteris , comes from the Greek words lasios, meaning “shaggy” or “hairy,” and nykteris , meaning “bat.” The specific name comes from the Latin words for “night,” nox, and “wanderer,” vagari (Stangl et al. 1993). Subspecies. Lasionycteris noctivagans Le Conte, 1831, is a monotypic species, and no subspecies are recognized. Description. This medium-sized (forearm = 37–44 mm) bat is easily recognized by its distinctive pelage coloration. It is entirely black, but individual hairs of the dorsal surface are partially white near the ends, giving the pelage a frosted appearance . The ears are dark, short, and rounded with a paler patch at the base. The tragus is short and curved forward. The upper surface of the interfemoral membrane is furred, though not as heavily as in the tree bats of the genus Lasiurus. Other bats that have similar pelage include the hoary bat (Lasiurus cinereus ), which is much larger and grayer, and the eastern (Lasiurus borealis) and western (Lasiurus blossevillii) red bats, which are reddish rather than black. Dental formula: I 2/3, C 1/1, Pm 2/3, M 3/3 × 2 = 36 (it is easy to overlook the upper incisors and first lower premolars because they are very small). Females are slightly larger than males. Average external measurements are as follows: total length, 96 mm; tail, 38 mm; hind 23 (34.8%) bats submitted over a 9-year period tested positive for rabies (Constantine et al. 1979). In 2010, the first specimens were submitted to the DSHS for rabies testing, and 3 from El Paso County were found to be positive (Tipps et al. in press). Status. The IUCN 2011 status of the western yellow bat is “least concern.” In Texas and elsewhere the species has expanded its range northward (O’Farrell et al. 2004). There appears to be an established population in Brewster County, Texas, where it is encountered most often in the fall. Additional fieldwork is needed to ascertain the status of this species in other regions of Texas. Remarks. Until 1988 L. xanthinus was recognized as a subspecies of L. ega (L. e. xanthinus), at which time it was elevated to specific status based on genetic evidence (Baker et al. 1988). Additionally, the species most morphologically similar to L. xanthinus, L. ega, is actually more closely related to L. intermedius than it is to L. xanthinus (Morales and Bickham 1995). Because of these taxonomic changes, older references that mention L. ega in the southwestern United States are usually referring to L. xanthinus. Lasiurus ega occurs in southern Texas, as described in its species account. Specimens Examined. Go to www.batsof texas.com for more detailed information about the total of 8 specimen records of L. xanthinus from Texas. Additional records: Brewster County (1) (Bradley et al. 1999), Jeff Davis County (1) (Jones et al. 1999). References. 92, 101, 165, 178, 193, 212, 256, 275, 282, 283, 423, 476, 565, 567, ...