Most studies on bats in Taiwan concentrate in taxonomy, reproduction, activity patterns, and behaviors. However, researchers seldom focus to understand the patterns and functions of bat echolocation in Taiwan. Using a sophisticated Anabat II bat detector system, I was able to collect echolocation calls of bat species including Pipistrellus abramus, Miniopterus schreibersii, Rhinolophus monoceros, and Hipposideros terasensis in southern Taiwan. Between these four bat species, R. monoceros has the highest frequency and P. abramus has the lowest frequency of echolocation calls. The echolocation calls that used by P. abramus belong to FM/CF type, with the maximum frequency at 53.30¡Ó5.30¡]mean ¡ÓS.D.¡^kHz, the minimum frequency at 46.74¡Ó1.94 kHz, the duration time at 5.97¡Ó1.53 msec, the frequency range at 6.55¡Ó4.29 kHz, and the frequency change rate at 2.65¡Ó2.21 kHz/msec. The echolocation calls that used by M. schreibersii belong to FM/CF type, with the maximum frequency at 65.12¡Ó12.24 kHz, the minimum frequency at 49.71¡Ó1.48 kHz, the duration time at 3.62¡Ó2.06 msec, the frequency range at 15.42¡Ó11.79 kHz, and the frequency change rate at 9.52¡Ó7.95 kHz/msec. The echolocation calls that used by H. terasensis belong to CF/FM type, with the maximum frequency at 68.16¡Ó0.86 kHz, the minimum frequency at 61.50¡Ó8.72 kHz, the duration time at 11.27¡Ó4.88 msec, the frequency range at 6.66¡Ó8.87 kHz, and the frequency change rate at 4.67¡Ó3.19 kHz/msec. The echolocation calls that used by R. monoceros belong to FM/CF/FM type, with the maximum frequency at 112.55¡Ó1.65 kHz, the minimum frequency at 89.57¡Ó18.03 kHz, the duration time at 34.30¡Ó9.13 msec, the frequency range at 22.98¡Ó17.75 kHz, and the frequency change rate at 7.70¡Ó4.20 kHz/msec. R. monoceros¡]duty cycle 65 %¡^and H. terasensis ¡]duty cycle 39 %¡^are the high duty cycle bats. P. abramus¡]duty cycle 12 %¡^ and M. schreibersii¡]duty cycle 11 %¡^are the low duty cycle bats. High duty cycle bats have more stable maximum frequency of echolocation calls than low duty cycle bats. Low duty cycle bats have more stable minimum frequency of echolocation calls than that of high duty cycle bats. I compared the differences in echolocation calls emitted by these four bat species. I used the Dumcam¡¦s multiple-range test to confirm these echolocation calls have significant differences (p¡Õ0.05) in their maximum frequency, minimum frequency, frequency change rate, frequency range and duration of time. Similarly, I also used these five variables to run canonical discriminate analysis. The Mahalanobis distance¡¦s between pair of species varied from 12.01 (P. abramus A type and H. terasensis) to 197.80 (P. abramus A type and R. monoceros); all distances were statistically significant (p<0.01). These results confirm the fact that bats¡¦ echolocation calls can be used to clearly identify individual species, which is not only possible but also practicable. However, considering the possibilities of some habitat influence and geological/genetic difference, using echolocation for identification species should be done more cautiously.

LD2668 .T4 1966 B435 / Master of Science

ABSTRACT The conservation of cetaceans in Pescadores was originated in 1990. However, the conflict between the fishery loss and cetacean protection keeps growing. The fishery loss caused by cetaceans are mainly: ¡§steal fish¡¨ and ¡¨frighten fish group¡¨, and the others like ¡¨damage fishing gear¡¨ and ¡¨interfere fishing operation¡¨, and etc.By the understanding of dolphins behavior, this study proposed acoustical deterrent methods; 1.harassment:look for echolocation system frequency range, and broadcast disarrange signals to produce an illusion, and prevent dolphins from locating the target. 2. threat: broadcast sounds of its predators which is killer whales to scare dolphins from approaching the fishing vessels. 3. warning: loud noise or alert sounds of dolphins. The circuits of generating above sounds are designed, test and modified after the field test . Underwater speaker was used to broadcast sounds of 10 kHz , 20 kHz , killer whales sound and distress call of dolphins. The test results showed these dolphins avoided the sound source, especially during killer whales sound and stress call of dolphins. They were effective to deter dolphins to reduce stealing fish on the sea. More effective deterrence device should be developed through this study to reduce the loss of fisherman, and achieve the cetacean conservation goal.

Thesis (Ph. D.)--University of Texas at Austin, 2000. / Vita. Includes bibliographical references. Available also from UMI/Dissertation Abstracts International.

Thesis (Ph. D.)--University of Texas at Austin, 2000. / Vita. Includes bibliographical references (leaves 126-134). Available also in a digital version from Dissertation Abstracts.

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To measure thresholds of human echolocation ability researchers need an automated system for the possibility to present a large set of stimuli. Previous studies have used recorded sounds or simulated sounds, allowing strict stimulus control at the expense of ecological validity. The purpose of this experiment was to test an automated system, that uses real objects. Fifteen participants tried the system and the task was to detect the presence of a disc, only using sound reflections. Detection thresholds as a function of distance to the reflecting object were determined using an adaptive staircase method. The mean threshold across participants was 1.7 m, which is in line with previous studies, using earphone presented sounds. Fairly large variability across individuals was observed. Two individuals performed very well with thresholds of &gt; 2.5 m. Overall, the present experiment shows that the automated measuring system works well for assessing human echolocation ability.

To measure thresholds of human echolocation ability researchers need an automated system for the possibility to present a large set of stimuli. Previous studies have used recorded sounds or simulated sounds, allowing strict stimulus control at the expense of ecological validity. The purpose of this experiment was to test an automated system, that uses real objects. Fifteen participants tried the system and the task was to detect the presence of a disc, only using sound reflections. Detection thresholds as a function of distance to the reflecting object were determined using an adaptive staircase method. The mean threshold across participants was 1.7 m, which is in line with previous studies, using earphone presented sounds. Fairly large variability across individuals was observed. Two individuals performed very well with thresholds of &gt; 2.5 m. Overall, the present experiment shows that the automated measuring system works well for assessing human echolocation ability.

Resident killer whales (Orcinus orca) in the Salish Sea use echolocation clicks to hunt for Chinook salmon, their preferred prey. An increase in underwater anthro- pogenic noise in recent decades has been identified as a threat to their survival due to auditory masking effects on these signals. Studies quantifying the effects of anthro- pogenic noise on echolocation signals have yet to be carried out due to a data gap for echolocation acoustic characteristics. In particular, to date, only one study has reported click characteristics for northern resident killer whales, and no results have been reported for southern residents. This thesis reports on acoustic recordings of resident killer whale echolocation clicks gathered over two summers in several loca- tions around Vancouver Island, and spectral and temporal characteristics extracted from them. Acoustic characteristics are reported separately for southern and north- ern resident killer whales based on 708 clicks from 19 click trains and 1277 clicks from 16 click trains, respectively. Results are further categorized into click type (slow, fast, and buzz clicks) based on inter-click interval, an indicator of foraging phase. Results show no differences in acoustic characteristics between the northern and southern killer whales, suggesting echolocation clicks do not vary between these subspecies. No significant differences are noted between slow- and fast-click characteristics, while buzz clicks appear to have some significant differences in characteristics from the oth- ers. Apparent source level values for northern and southern killer whales vary between 179-221 dB re 1 μPa at 1 m and 192-220 dB re 1 μPa at 1 m, respectively, based on the largest amplitude click from each click train (assumed to be directed towards the recording array). The values reported in this thesis will be used in subsequent noise modelling studies to quantify the effects of anthropogenic noise on resident killer whale ability to hunt for prey via echolocation signals. / Graduate