Seasonality and fidelity in roost use of the Mexican free-tailed bat, Tadarida brasiliensis , in an urban setting

We studied 7 urban roosts occupied by Mexican free-tailed bats ( Tadarida brasiliensis ) in downtown Waco, Texas, from August 2001 to September 2002. We examined frequency of roost use, colony sizes, and roost fidelity in relation to gender. Use of roosts and colony sizes were highest in the fall and lowest in the winter, but fluctuated widely during the study. These roosts were not used by maternity colonies, and patterns of occupancy suggested that they served as stopover sites during migratory seasons. Individual bats exhibited high fidelity to discrete roosts included in the study. However, the bats commonly left the study area, suggesting that populations are defined at greater spatial scales than we included in this study. Male bats were recaptured more often and spent more days in the study area than female bats, suggesting a sexual difference in roosting behavior.     

Local distribution and foraging behavior of the spotted bat ( Euderma maculatum ) in worthwestern Colorado and adjacent Utah

This study investigated local distribution and foraging behavior of the spotted bat ( Euderma maculatum ) in Dinosaur National Monument, Colorado-Utah, by monitoring audible echolocation calls. The occurrence of this species was verified in a variety of habitat types in canyon bottoms and other relatively low elevation sites, indicating that the animals were widely distributed and locally common in the area. Foraging spotted bats concentrated flight activity in the open-air space above meadows occasionally exploited near-canopy habitat (within 8 m of foliage). Bats began to forage shortly after dark, and activity levels were relatively constant throughout the night. Foraging spotted bats attacked airborne prey every 2.15 min on average. Consistent with published observations, spotted bats maintained exclusive foraging areas. Distinct vocalizations indicating agonistic encounters occurred when a bat encroached on the foraging area of a conspecific.     

Distribution, foraging behaviour, and capture results of the spotted bat ( Euderma maculatum ) in central Oregon

The spotted bat ( Euderma maculatum ) has been virtually unknown in Oregon despite the existence of potential habitat in many areas of the state. In 2002 and 2003 we searched for spotted bats along the John Day, Deschutes, and Crooked Rivers and at a remote dry canyon southeast of the city of Bend in central Oregon. The species was documented through the use of mist-nets, a bat detector, and recognition of audible spotted bat calls. Spotted bats were found at 11 locations in 6 Oregon counties. Nightly activity patterns of spotted bats were unpredictable. Spotted bats were found in 78% of search areas but on only 48% of survey nights. We observed spotted bats foraging above fields and low upland slopes adjacent to rivers and creeks and along the rims of cliffs. Estimated flying heights of spotted bats ranged from 3 m to 50 m aboveground. The species was difficult to capture and was captured only after considerable experimentation with methods and materials. Three spotted bats were captured toward the end of the project in 2003 and accounted for only 0.5% of all bats captured during the study. Although we attached radio transmitters to 2 spotted bats, we found no roost locations. We believe additional spotted bat surveys in Oregon are warranted, especially in higher-elevation habitats, but recommend that to increase their effectiveness, surveys accommodate the unique foraging behavior of the species.     

Roost sites of the silver-haired bat ( Lasionycyeris noctivagans ) in the Black Hills, South Dakota

We investigated the roosting ecology of silver-haired bats ( Lasionycteris noctivagans ) in the Black Hills, of western South Dakota. Using radiotelemetry, we located 39 roosts, 10 of which were maternity aggregations containing 6 to 55 bats. The roosts were mostly in ponderosa pine ( Pinus ponderosa ) snags that averaged 39 cm diameter at breast height. Solitary bats preferred roosting under loose bark or in crevices in trees, regularly moving among trees. All maternity aggregations were found in tree cavities, primarily those created by woodpeckers. Roost trees were located in patches of forest with relatively high snag densities, about 21 snags/ha. This study suggests that snags play an important role in maintain silver-haired bat populations in ponderosa pine ecosystems.     

Foraging ecology and behaviour of the ponerine ant Ectatomma opaciventre Roger in a Brazilian savannah

This study provides a detailed account of the foraging behaviour of the ponerine ant Ectatomma opaciventre in a ‘cerrado’ savannah in south-east Brazil. Our observations suggest that this species has an exclusively diurnal foraging pattern. Feeding habits included both predation and scavenging, with termite workers and leaf-cutting ants as the most important food items. Contrary to all other Ectatomma species studied to date, no liquid food such as hemipteran honeydew or plant nectar was collected. Foragers showed clear individual foraging area fidelity.Workers of E. opaciventre employed a typical individual foraging strategy, i.e. there was no co-operation between foragers in the search for or retrieval of food, neither by tandem running nor by trail laying. Nest density was considerably lower than in other Ectatomma (0.015 nests per m²). The observed mean distance to the nearest neighbouring nest was 5.85 m, with a significant tendency toward over-dispersion. Nests were more frequently found in specific microhabitats, which may suggest active choice of nesting site by founding queens.     

On the structure and funtion of white-tailed prairie dog burrows

The architecture of burrows of the white-tailed prairie dog ( Cynomys leucurus ) is poorly known. For this reason and for comparative purposes, one recenlty active burrow of this species was excavated in southern Montana; the detailed methodology is described. Data were compiled on the dimensions of 29.3 m of excavated passages, and interpretations of several features are discussed. A ""turning bay,"" sleeping quarters, two hibernacula, and a maternity area are described, the last feature for the first time in print. In addition, we report Cynomys using their teeth to dig, also for the first time. Further, an inadvertent remodeling of the burrows is ascribed to normal animal traffic and appears to confirm a prediction based on late Pleistocene fossil burrows in Alberta.     

Foraging ecology of the giant Amazonian ant Dinoponera gigantea (Hymenoptera,Formicidae, Ponerinae): activity schedule,diet and spatial foraging patterns

This study provides a detailed account of the natural history and foraging biology of the ponerine ant Dinoponera gigantea in a rainforest in north Brazil. The species nests on the ground and the colonies contain 70–96 workers. Ant activity is negatively correlated with temperature, and is more intense at dawn and dusk. Foragers leave the nest independently and search for food individually on the leaf litter, within ca 10 m around the nest. Workers are opportunistic feeders that collect seeds and fruits, and hunt for live prey as well as scavenge for dead animal matter. The dry weight of food items ranges from <10 mg (spiders, insect parts) to >400 mg (seeds, fruits). There is no nestmate recruitment during the search for or retrieval of food, irrespective of food type and size. Foragers have a high directional fidelity, and ants from neighbouring colonies may engage in ritualized territorial contests at the border of their foraging areas. The foraging ecology of D. gigantea is compared with other ponerine species living in tropical forests, as well as with other ant groups showing similar behavioural patterns.     

Phyllostomid bats flying in daylight: a case from the Neotropics

Bats (Chiroptera), one of the most diverse groups in terms of taxonomy, morphology and ecology, are known for their nocturnal behaviour of flight and feeding. Although there is no consensus on the evolution of nocturnality in bats, many authors mention risk of predation, overheating, competition and mobbing by non-competitor species as arguments to justify nocturnal instead of daytime flight in bats. Herein we describe the first records of three genera of phyllostomid bats flying, foraging and drinking water during daytime in the Brazilian Amazon. All taxa were recorded drinking water, and some Phyllostomus sp. individuals were recorded foraging on termites, alongside birds. Risk of dehydration and overheating in roosts, as well as low competition in daytime, may explain the emergence of phyllostomid bats before sunset.     

Bats of the White and Inyo Mountains of California-nevada

We surveyed bats throughout the White and Inyo Mountains of California and Nevada. From December 1990 to November 1996, we surveyed hibernating bats, and foraging bats from June 1992 to September 1996. The White-Inyo Range rests in a unique biogeographical junction between the Sierra Nevada, Mojave Desert, and Great Basin Regions. Elevational gradients of 305-4340 m, combined with limited human development, further enhance the interest of natural history and faunal distributions in this range. We found 13 bat species in the course of 2668 observations. Three of these species, the spotted bat ( Euderma maculatum ), silver-haired bat ( Lasionycteris noctivagans ), and hoary bat ( Lasturus cinereus ), have no previous records from the White-Inyo Range. We found bats in all vegetation zones except alpine, 3500-4342 m. Despite an abundance of mines in this range, only Townsend's big-eared bat ( Corynorhinus townsendii ) and western small-footed myotis ( Myotis ciliolabrum ) used them routinely. Our data also indicated the importance of surface water to bat populations in arid regions.     

Habitat utilization by juvenile hawksbill turtles (Eretmochelys imbricata,Linnaeus, 1766) around a shallow water coral reef

Contemporary studies of sea turtle diving behaviour are generally based upon sophisticated techniques such as the attachment of time depth recorders. However, if the risks of misinterpretation are to be minimized, it is essential that electronic data are analysed in the light of first-hand observations. To this aim, we set out to make observations of juvenile hawksbill turtles (Eretmochelys imbricata, Linnaeus, 1766) foraging and resting in a shallow water coral reef habitat around the granitic Seychelles (4°'S, 55°'E). Data were collected from six study sites characterized by a shallow reef plateau (<5 m) and a flat sandy area at the base of the reef face (<10 m). Observation data were categorized into the following behaviours: (1) stationary foraging; (2) active foraging; (3) resting; and (4) assisted resting. Central to this investigation was the development of a technique for accurately estimating the size of sea turtles in situ based upon previously tested techniques for reef fishes. This revealed that through calibration, the curved carapace length (CCL) of marine turtles can be consistently estimated to within 10 cm of their actual size. Although rudimentary, this has advantages for assessing the residency or absence of specific life history stages from particular environments. Indeed, our data supported previous claims that following the reproductive season, adult hawksbills in the region may move away from the nesting beaches to alternative foraging grounds whilst immature turtles (following the pelagic juvenile stage) may opt to reside in areas close to their natal beaches. With regards to habitat utilization, juvenile hawksbills displayed an alternating pattern of short, shallow foraging dives followed by deeper, longer resting dives. These findings are consistent with previous electronic studies of free-range diving in this species and suggest that the maximization of resting duration may be an important factor driving this behaviour.     

Winter habitat selection patterns of Merriam's turkeys in the southern Black Hills, South Dakota

In northern areas of their expanded range, information on Merriam's turkeys ( Meleagris gallopavo merriami ) is lacking, specifically pertaining to wintering behavior and factors associated with winter habitat selection. Forest managers need detailed quantification of the effects of logging and other management practices on wintering habitats needed by Wild Turkeys and other wildlife. Therefore, we examined winter habitat selection patterns within ponderosa pine ( Pinus ponderosa ) forests and determined factors associated with use of farmsteads by Merriam's turkeys in the southern Black Hills, South Dakota. We radio-marked 86 female Merriam's turkeys (70 adults and 16 yearlings) and monitored them during winter (1 December–31 March), 2001–2004. Female Wild Turkeys used recently burned pine forest less than expected but selected farmsteads and stands of mature ponderosa pine ( 22.9 cm diameter at breast height [DBH] trees) for foraging sites. Within forests, female Wild Turkeys selected foraging sites with less understory vegetation and visual obstruction, and larger-diameter ponderosa pine. Ponderosa pine seed abundance varied among years, and pine seeds were most abundant in stands of 30–35 cm DBH with basal area of 22–28 m2 ? ha–1. Abundance of pine seeds may have influenced use of farmsteads by Wild Turkeys, more so than ambient temperatures or snow depth. In the southern Black Hills, management should emphasize open- to mid-canopy and mature-structural-stage pine stands, where seed production was greatest. During winters when mast from pine is unavailable, farmsteads likely provide nutritional supplementation and may be important for maintaining Merriam's turkey populations.     

New distributional records for spotted bat ( Euderma maculatum ) in Wyoming

Before 1990 the spotted bat ( Euderma maculatum ) was known in Wyoming from only 2 records. Between June 1994 and May 1997 we documented habitat use and observations incidental to conducting a bat inventory of caves and abandoned mines. By monitoring audible echolocation calls, we observed bats at mist-netting sites. Spotted bats were heard or captured on 13 nights at 10 locations, all of which were near canyons or high cliff faces. No foraging habitat preferences were noted. E. maculatum occurrence appears to be related to roost structure, roost availability, and proximity to a permanent water source.     

Distribution, movements, and habitat use of razorback sucker ( Xyrauchen texanus ) in a lower Colorado River reservoir, Arizona-Nevada

Distribution, movements, and habitat use of 10 wild adult razorback suckers ( Xyrauchen texanus ) were examined in Lake Mohave, Arizona-Nevada, from November 1994 through July 1997. Movement rates (0.00-17.35 km d -1 ) and ranges ( x = 39 km) were similar to those for riverine populations. All study fish returned to spawning sites used in previous years, but they also visited other spawning areas. Spawning females were significantly ( P = 0.031) more active than males (480 vs. 87 m d -1 ) and moved substantial distances between spawning sites during peak reproduction (1-28 February). Fish became most active (m d -1 , km month -1 ) after spawning and moved to areas known to support higher algal production. Fish were typically within 50 m ( P 30.0 m). Adults were detected throughout the available thermal gradient (12°-30°C), but during summer typically had body temperatures between 18° and 22°C. Vertical movements within the water column showed no correlation with depth or time of day, but seasonal shifts suggest fish may regulate body temperature by seeking specific temperatures during reservoir stratification.     

Movements by small mammals on a radioactive waste disposal area in southeastern Idaho

Average linear movement by populations of Dipodomys ordii, Microtus montanus, Perognathus parvus, and Peromyscus maniculatus &nbsp; was investigated over a 15-month period by live trapping on a low-level, radioactive waste disposal area in Idaho. No significant differences in movement among habitats were observed seasonally, excepting M. montanus in spring. Average linear movements within habitats ranged from 20 to 70 m for all species, but some patterns varied seasonally and among age classes for individual species. Although predation on contaminated small mammals from the disposal area is a vector of radionuclide transport, local movements by these rodents do not appear to be of sufficient magnitude to contribute significantly to redistribution of radioactive particles.     

Hip glands in a natural population of montane voles ( Microtus montanus )

Average linear movement by populations of Dipodomys ordii, Microtus montanus, Perognathus parvus, and Peromyscus maniculatus &nbsp; was investigated over a 15-month period by live trapping on a low-level, radioactive waste disposal area in Idaho. No significant differences in movement among habitats were observed seasonally, excepting M. montanus in spring. Average linear movements within habitats ranged from 20 to 70 m for all species, but some patterns varied seasonally and among age classes for individual species. Although predation on contaminated small mammals from the disposal area is a vector of radionuclide transport, local movements by these rodents do not appear to be of sufficient magnitude to contribute significantly to redistribution of radioactive particles.     

Roosting behavior of the Mexican free-tailed bat ( Tadarida brasiliensis ) in a highway overpass

A colony of Mexican free-tailed bats ( Tadarida brasiliensis ) roosting in an interstate highway overpass in Belton, Bell County, Texas, was studied weekly from 28 June to 21 November 1996 (except for the week of 4 July). We examined 2 aspects of roosting behavior: site-specific fidelity to locations within the roost and gender-related segregation within the roost. Colony estimates based on guano production showed a marked decrease in the number of bats from 19 to 26 July; many of these departing bats were adult females. No female bats sampled after this interval were pregnant. Male bats outnumbered females on nearly all sampling occasions. Throughout the study, one section of the roost was dominated by males, ranging from 83% to 100% of total bats. The majority of bats recaptured at least once were faithful to specific locations within the roost, and more than 70% of bats recaptured multiple times were faithful to specific roost locations.     

Relationships between insolation and rattlesnake hibernacula

We examined the relationship between insolation, climate, and hibernacula of black-tailed ( Crotalus molossus ), Great Basin ( Crotalus lutosus ), and western diamondback ( Crotalus atrox ) rattlesnakes at 4 sites in Arizona, Nevada, and Utah. Hibernacula were located through a combination of visual searches and radio telemetry from 1995 to 2003. We used global information systems to calculate insolation and compared hibernaculum insolation values with random points representing available insolation of the surrounding habitat. Insolation reflects soil temperatures, and we predicted that hibernacula in cool climates, at high elevations, and at high latitudes would have higher insolation relative to their surroundings, while hibernacula in warmer climates would not differ from their surroundings in insolation. Coolest temperatures, highest elevations, and highest latitudes occurred on the C. lutosus and C. molossus sites, where hibernaculum insolation was higher than surrounding insolation. Temperatures were intermediate on the high-elevation C. atrox site, where hibernaculum insolation did not differ from random-point insolation. Temperatures were highest on the low-elevation C. atrox site, where hibernaculum insolation was unexpectedly lower than random-point insolation. Our observations suggest that rattlesnakes in cool climates utilize hibernacula with insolation values higher than those of their surroundings. Rattlesnakes in warm climates utilize hibernacula with insolation values lower than or similar to those of their surroundings.     

Swift fox response to prescribed fire in shortgrass steppe

Swift foxes ( Vulpes velox ) are shortgrass specialists and as a result are heavily dependent upon grassland disturbance regimes to maintain high-quality habitat. To better understand this relationship, we monitored the movement and spatial ecology of resident swift foxes before and after a 2005 prescribed burn in southeastern Colorado. We hypothesized that foxes would shift home ranges into and increase foraging activity within the prescribed burn area. Foxes did appear to alter their space-use patterns in response to the burn, although the response was constrained by territoriality. Foxes whose core-use areas overlapped the burn increased their use of the burn area for foraging and denning, but we did not observe shifts of individual home ranges to encompass more of the burned area. Foxes whose coreuse areas did not overlap the burn did not alter their space use or change home range boundaries in response to the burn. Because we observed only positive or neutral responses to prescribed burning, we recommend this tool as an appropriate method to maintain high-quality swift fox habitat.     

Spotted bats ( Euderma maculatum ) from Mt. Taylor, New Mexico

The spotted bat ( Euderma maculatum ) is an elusive and rarely captured species in western North America. In the United States, it is known from 12 western states. In New Mexico, few individuals have been reported in recent years, and multiple individuals are known from 9 of 12 capture sites. This study reports on additional captures of E. maculatum from Mt. Taylor (Cibola County) for 2 consecutive summers and includes evidence of a reproducing population in the area. On 30 June/1 July 2006, I captured 4 individuals of E. maculatum , including a lactating female, and on 5 June 2007, I captured a nonreproductive female. The flight of this species was directional and deliberate; I captured 5 of 6 spotted bats that came low over the earthen pond. This study demonstrates how human-made sources of water in an arid region provide opportunities for many species of bats to drink.     

Influence of water size and type on bat captures in the lower Sonoran Desert

We compared bat use by mist-netting at 4 different types of wildlife water developments in southwestern Arizona during summer 2000 and 2001. Scaling our results by netting effort, we caught bats more frequently and observed higher species diversity at tinajas (modified natural rock pools) with larger open-water area compared with ""guzzler"" type water developments that had less open water and more obstacles to bat flight. We caught the fewest bats at guzzlers with buried concrete vault drinkers, which impede bat access and have the smallest areas of open water. Water development designs that minimize evaporative water loss by reducing the amount of open water apparently reduce use by bats in this area.