@article {53241, title = {A 2.6-gram sound and movement tag for studying the acoustic scene and kinematics of echolocating bats}, journal = {Methods in Ecology and Evolution}, year = {2018}, month = {Apr-10-2019}, abstract = {

1.To study sensorimotor behaviour in wild animals, it is necessary to synchronously record the sensory inputs available to the animal, and its movements. To do this, we have developed a biologging device that can record the primary sensory information and the associated movements during foraging and navigating in echolocating bats.

2.This 2.6 -gram tag records the sonar calls and echoes from an ultrasonic microphone, while simultaneously sampling fine-scale movement in three dimensions from wideband accelerometers and magnetometers. In this study, we tested the tag on an European noctula (Nyctalus noctula) during target approaches and on four big brown bats (Eptesicus fuscus) during prey interception in a flight room.

3.We show that the tag records both the outgoing calls and echoes returning from objects at biologically relevant distances. Inertial sensor data enables the detection of behavioural events such as flying, turning, and resting. In addition, individual wing-beats can be tracked and synchronized to the bat\&$\#$39;s sound emissions to study the coordination of different motor events.

4.By recording the primary acoustic flow of bats concomitant with associated behaviours on a very fine time-scale, this type of biologging method will foster a deeper understanding of how sensory inputs guide feeding behaviours in the wild.

}, keywords = {Accelerometers, archival tag, auditory scene, bat echolocation, biologging, echogram, echoic scene, flight kinematics, inertial sensors, sensory-motor response}, doi = {10.1111/2041-210X.13108}, url = {http://doi.wiley.com/10.1111/2041-210X.13108}, author = {Stidsholt, Laura and Johnson, Mark and Beedholm, Kristian and Jakobsen, Lasse and Kugler, Kathrin and Brinkl{\o}v, Signe and Salles, Angeles and Moss, Cynthia F.} } @article {53232, title = {Practical implementation of auditory time and frequency weighting in marine bioacoustics}, journal = {Applied Acoustics}, volume = {145}, year = {2019}, month = {Jan-02-2019}, pages = {137 - 143}, abstract = {

Much effort is currently directed at describing the behavioral reactions of marine mammals following exposure to sound with the aim of deriving generalized thresholds and dose-response functions. The perceived loudness of a given sound is a candidate for a common metric for sound exposure. The loudness of a signal relates to various factors, including the stimulus duration and frequency content, and it can be approximated by an appropriate time and frequency weighting of the signal. Auditory frequency weighting is achieved by applying a frequency weighting function (band-pass filter), with a frequency response resembling the shape of an inverted audiogram. Temporal weighting may be achieved by computing the running rms-average (Leq) with a time constant that is comparable to that of the mammalian auditory system. The practical implementation of such weighting functions are presented in the form of Matlab functions. These functions generate output signals that are weighted according to current recommendations for different groups of marine mammals. With these functions, it is possible to derive the weighted peak Leq of a signal, which is likely to be a good proxy for the loudness of the signal. Ultimately, this weighted level is conjectured to be a predictor of behavioral response of marine mammals to the sound.

}, issn = {0003682X}, doi = {10.1016/j.apacoust.2018.09.022}, url = {https://linkinghub.elsevier.com/retrieve/pii/S0003682X18303967https://api.elsevier.com/content/article/PII:S0003682X18303967?httpAccept=text/xmlhttps://api.elsevier.com/content/article/PII:S0003682X18303967?httpAccept=text/plain}, author = {Tougaard, Jakob and Beedholm, Kristian} } @article {53024, title = {Variability of the inter-pulse interval in sperm whale clicks with implications for size estimation and individual identification}, journal = {The Journal of the Acoustical Society of America}, volume = {144}, year = {2018}, month = {Jan-07-2018}, pages = {365 - 374}, abstract = {

Sperm whales generate multi-pulsed clicks for echolocation and communication with an inter-pulse interval (IPI) determined by the size of their hypertrophied sound producing nose. The IPI has therefore been used to estimate body size and distinguish between individuals, and it has been hypothesized that conspecifics may use IPIs to recognize each other. However, the degree to which IPIs vary within individuals has not explicitly been tested, and therefore the inherent precision of this measure and its applicability for size estimation for researchers and sperm whales alike remain unknown. Here, the variability in IPI from both animal-borne Dtags and far-field recordings from echolocating and communicating sperm whales is quantified. Three different automatic methods (envelope, cepstrum, and cross-correlation) are tested and it is found that the envelope approach results in the least dispersion. Furthermore, it is shown that neither growth, depth, nor recording aspect fully explains the observed variability among clicks recorded from the same individual. It is proposed that dynamics in the soft structures of the nose are affecting IPIs, resulting in a variation of approximately 0.2\ ms. Therefore, it is recommended that this variation be considered in IPI studies and that IPIs may have limited functionality as an identity cue among large groups of conspecifics.

}, issn = {0001-4966}, doi = {10.1121/1.5047657}, url = {http://asa.scitation.org/doi/10.1121/1.5047657}, author = {B{\o}ttcher, Anne and Gero, Shane and Beedholm, Kristian and Whitehead, Hal} }