29 research outputs found
Data from: The Chirocopter: a UAV for recording sound and video of bats at altitude
1. Most recordings of bats are conducted with fixed equipment, which relies on opportunistic data collection. Unmanned aerial vehicles (such as drones) are considered inappropriate for recording bats due to ultrasound noise constraints.
2. We developed a UAV system that physically isolates UAV noise so we can record, with 3D maneuverability, ultrasonic audio and spatial thermal data of bat flight at altitude.
3. We tested the noise of our UAV with various payloads and microphone configurations to characterize the ultrasonic noise of our system, physically isolate drone noise from the microphone, and maximize UAV flight performance.
4. Over 84 minutes of recordings, we captured 3,847 echolocation signals from bats with corresponding thermal data of bat flight. Our system provides a feasible mechanism to capture both acoustic and video data of bats aloft at flexible locations and altitudes.
5. We include information on how to extend our method to apply to acoustic recordings in the audible (20 Hz-20 kHz) range for recording sounds of other taxa
Variation in Bat Guano Bacterial Community Composition With Depth
Bats are known to be reservoirs for a variety of mammalian pathogens, including viruses, fungi, and bacteria. Many of the studies examining the microbial community inhabiting bats have investigated bacterial taxa found within specific bat tissues and isolated bat guano pellets, but relatively few studies have explored bacterial diversity within bat guano piles. In large bat caves, bat guano can accumulate over time, creating piles several meters deep and forming complex interactions with coprophagous organisms in a habitat with low light and oxygen. As the guano decays, the nutrient composition changes, but the bacterial communities deep within the pile have not been characterized. Here, we assess the bacterial communities across varying depths within the guano pile using both culture-independent and culture-dependent methods. We found that although similar taxa are found throughout the guano pile, the relative abundances of taxa within the pile shift, allowing certain taxa to dominate the bacterial community at varying depths. We also identified potential bacterial functions being performed within the bat guano as various depths within the pile and found little variation in terms of the dominant predicted functions, suggesting that although the relative abundances of bacterial taxa are changing, the functions being performed are similar. Additionally, we cultured 15 different bacterial species, including 2 not present in our culture-independent analysis, and discuss the pathogenicity potential of these taxa. This study represents the first characterization of the bacterial community from the extreme environment within a bat guano pile and demonstrates the potential for bat caves as resources for identifying new bacterial species
Echolocation while drinking: Pulse-timing strategies by high- and low-frequency FM bats.
During nightly foraging activity, echolocating bats drink by flying low over the water surface and dipping the lower jaw while avoiding further bodily contact with the water. This task poses different sensorimotor challenges than flying in the open to forage for insects. Of interest is how bats adjust the timing of their echolocation pulses to accommodate the surrounding scene, from the progressively nearer water surface itself to objects at longer distances. Drinking behavior has been described in only a few of the roughly 1,000 echolocating bat species, and in none of the 110 species in the Indian subcontinent. Here, we describe how bats emitting frequency-modulated (FM) echolocation pulses behaved while drinking from a swimming pool in urban northeast India. At least two different bat species were present, using 1st-harmonic frequencies sweeping down to about 35 Hz ("low frequency") and down to about 50 kHz ("high frequency"), separable at a 40 kHz boundary. Over entire drinking maneuvers, intervals between broadcast pulses accommodate both the proximate task of registering the water surface while drinking and registering echoes from the farther reaches of the scene. During approach to the water, both low and high frequency bats emit longer, more stable interpulse intervals that matched the time interval covering echo arrival-times out to the frequency-dependent maximum operating range. High frequency bats use shorter interpulse intervals than low frequency bats, consistent with the shorter operating range at higher frequencies. Bats then accelerate their pulse rate to guide the dive down to drinking, with low frequency bats continuing to decrease pulse intervals and high frequency bats maintaining a more steady interval during the drinking buzz. The circumstance that both groups were engaged in the same task made this a natural experiment on the behavior during approach
Table_2_Variation in Bat Guano Bacterial Community Composition With Depth.xlsx
<p>Bats are known to be reservoirs for a variety of mammalian pathogens, including viruses, fungi, and bacteria. Many of the studies examining the microbial community inhabiting bats have investigated bacterial taxa found within specific bat tissues and isolated bat guano pellets, but relatively few studies have explored bacterial diversity within bat guano piles. In large bat caves, bat guano can accumulate over time, creating piles several meters deep and forming complex interactions with coprophagous organisms in a habitat with low light and oxygen. As the guano decays, the nutrient composition changes, but the bacterial communities deep within the pile have not been characterized. Here, we assess the bacterial communities across varying depths within the guano pile using both culture-independent and culture-dependent methods. We found that although similar taxa are found throughout the guano pile, the relative abundances of taxa within the pile shift, allowing certain taxa to dominate the bacterial community at varying depths. We also identified potential bacterial functions being performed within the bat guano as various depths within the pile and found little variation in terms of the dominant predicted functions, suggesting that although the relative abundances of bacterial taxa are changing, the functions being performed are similar. Additionally, we cultured 15 different bacterial species, including 2 not present in our culture-independent analysis, and discuss the pathogenicity potential of these taxa. This study represents the first characterization of the bacterial community from the extreme environment within a bat guano pile and demonstrates the potential for bat caves as resources for identifying new bacterial species.</p
Data from: Estimating colony sizes of emerging bats using acoustic recordings
The decline of bats demands more widespread monitoring of populations for conservation and management. Current censusing methods are either prone to bias or require costly equipment. Here, we report a new method using passive acoustics to determine bat count census from overall acoustic amplitude of the emerging bat stream. We recorded the video and audio of an emerging colony of Mexican free-tailed bats from two cave locations across multiple nights. Instantaneous bat counts were calculated from the video frames, and the bat stream’s acoustic amplitude corresponding to each video frame was determined using three different methods for calculating acoustic intensity. We found a significant link between all three acoustic parameters and bat count, with the highest R2 of 0.742 linking RMS pressure and bat count. Additionally, the relationship between acoustics and population size at one cave location could accurately predict the population size at another cave location. The data were gathered with low-cost, easy-to-operate equipment, and the data analysis can be easily accomplished using automated scripts or with open-source acoustic software. These results are a potential first step towards creating an acoustic model to estimate bat population at large cave colonies worldwide
Model building using CSP
In the present work, we study algorithms for building finite models of sets of first-order axioms with the aim of proposing and implementing a new method, based on translation onto constraint satisfaction problem (CSP). In the theoretical part, we describe the standard MACE-style method, based on translating problems onto SAT, and advanced techniques that improve the effectiveness of this method: clause splitting, term definitions and static symmetry reduction. Next, we propose an alternative method, which translates problems onto CSP in a similar way. In addition, we have newly proposed a static symmetry reduction technique for binary functions. Next, we describe an implementation of the alternative method using a CSP-modelling language MiniZinc and a CSP-solver Gecode. Finally, we compare performance of our model finder against state-of-the-art representatives of standard methods, systems Paradox and Mace4
South_Video_Frames
Video frames for the South Cave, grouped into folders by da