Showing papers in "Bioacoustics-the International Journal of Animal Sound and Its Recording in 1997"

Identification of British bat species by multivariate analysis of echolocation call parameters

Abstract: 1. A method for the identification of bat species from time-expanded broad-band recordings of their echolocation calls is presented. The method may be used for the assessment of habitat use by bats. 2. Recordings were made of echolocation calls produced by 536 bats of known species identity, belonging to 15 species found in Great Britain. One call was analysed per individual, and sonograms and descriptive statistics of six time and frequency variables of calls are presented. British bats can be placed in three groups according to the structure of their calls: high duty cycle FM/CF/FM bats (Rhinolophus spp.), low duty cycle FM bats (Myotis spp. and Plecotus spp.) and intermediate duty cycle FM/CF bats (Pipistrellus and Nyctalus spp. and Eptesicus serotinus). 3. FM/CF/FM bats could be identified from the peak frequency of their calls. Two separate quadratic multivariate discriminant analyses were carried out on the time and frequency parameters of calls produced by FM bats and FM/CF bats. For FM ba...

Structure and function in whale ears

Abstract: Ultrasonic echolocation abilities are well documented in several dolphin species, but hearing characteristics are unknown for most whales. Vocalization data suggest whale hearing spans infra- to ultrasonic ranges. This paper presents an overview of whale ear anatomy and analyzes 1) how whale ears are adapted for underwater hearing and 2) how inner ear differences relate to different hearing capacities among whales. Whales have adaptations for rapid, deep diving and long submersion; e.g., broad- bore Eustachian tubes, no pinnae, and no air-filled external canals, that impact sound reception. In odontocetes, two soft tissue channels conduct sound to the ear. In mysticetes, bone and soft tissue conduction are likely. The middle ear is air-filled but has an extensible mucosa. Cochlear structures are hypertrophied and vestibular components are reduced. Auditory ganglion cell densities are double land mammal averages (2000–4000/mm). Basilar membrane lengths range 20–70 mm; gradients are larger than in ...

Computer-aided analysis of acoustic parameters in animal vocalisations: a multi-parametric approach

Abstract: The computer-aided analysis of acoustic signals of mammals is still a problem, as ofte (a) sound structures are complex, (b) vocal repertoires often comprise an enormou variety of vocalisations, (c) recordings are influenced by the acoustic conditions of th environment, and (d) the distance and spatial orientation of the sender to th microphone changes. In recent software packages for the analysis of acoustic signal procedures are integrated which allow the calculation of a variety of signal feature: However, these algorithms are often problematic under the conditions mentioned abovi In this paper, we present a multi-parametric approach which reduces these problem and which allows a quantitative and reproducible analysis of complex animi vocalisations. Our approach comprises the following aspects: (1) reduction of influence of recording conditions, (2) determination of different sound features and (3) calculatio of parameters to characterise these sound features. All calculations are done on the ...

Acoustic communication signals of mysticete whales

Abstract: Mysticete (baleen) whales produce a variety of vocalizations and sounds, but relatively few of these have been well described with accompanying behavior. This review concentrates on the vocalizations consistently associated with behavioral interactions or acoustic exchanges between or among conspecifics. These communication “signals” have been categorized for this review as contact calls of single animals outside of the breeding season (including cow-calf pairs), vocalizations reported during the breeding season (often designated as “songs”), and calls produced by active groups of whales that may or may not have a reproductive function. While much remains unknown, the data obtained thus far indicate that the social vocalizations of baleen whales have structural/functional similarities with those of other mammals and birds.

Development and social functions of signature whistles in bottlenose dolphins tursiops truncatus

Abstract: Bottlenose dolphins Tursiops truncatus produce individually distinctive signature whistles. Dolphins recognize the signature whistles of animals with which they share a social bond. Signature whistles develop within the first few months of life and are stable for a lifetime. Vocal learning appears to play a role in the development of signature whistles in bottlenose dolphins. The signature whistles of most female dolphins and about half of male dolphins differ from those of their mothers. Some dolphin calves born in captivity develop a signature whistle that matches either man-made whistles or those of an unrelated dolphin. Dolphins retain the ability as adults to imitate the whistles of animals with which they share strong individual-specific social relationships, bonds which may change throughout their lifetime. The exceptional imitative abilities of dolphin infants and the retention of this ability in adults may be related to the maintenance of changing individual specific social relationships...

Comparative analysis of swimbladder (drumming) and pectoral (stridulation) sounds in three families of catfishes

Abstract: Among teleosts, only representatives of several tropical catfish families have evolved two sonic organs: pectoral spines for stridulation and swimbladder drumming muscles. Pectoral mechanisms differ in relative size between pimelodids, mochokids and doradids, whereas swimbladder mechanisms exhibit differences in origin and insertion of extrinsic muscles. Differences in vocalization among families were investigated by comparing distress calls in air and underwater. High frequency broad-band pulsed sounds of similar duration were emitted during abduction of pectoral spines in all three families. Adduction sounds were similar to abduction signals in doradids, shorter and of lower sound pressure in mochokids, and totally lacking in pimelodids. Simultaneously or successively with pectoral sounds, low frequency harmonic drumming sounds were produced by representatives of two families. Drumming sounds were of similar intensity as stridulatory sounds in pimelodids, fainter in doradids, and not present in...

Echolocation in dolphins with a dolphin-bat comparison

Abstract: Dolphins possess a highly sophisticated auditory system and a keen capability for echolocation. Signals are emitted in the form of high intensity, short duration, broadband exponentially decaying pulses. The frequency spectra of echolocation signals used by many dolphins are dependent on the output intensity of the signals and not on any fine tuning by the animals. When the output intensity is low, the center frequency of the click tends to be low. As the output intensity increases, the center frequency also tends to increase. The pulses propagate from the dolphin's melon in a relatively narrow beam, and echoes are received via the lower jaw, with a slightly wider beam. Echo- locating dolphins can detect targets at ranges of approximately 100 plus meters, depending on the size of the targets. Target discrimination experiments have shown that dolphins can discriminate the shape, size, material composition and internal structure of targets from the echoes. The broadband short duration properties of...

Digital spectrographic cross-correlation: tests of sensitivity

Abstract: Digital spectrographic cross-correlation (SPCC), a technique described by Clark et al. (1987), simultaneously analyses frequency, amplitude and time components of a signal, and returns a single peak correlation coefficient. The procedure is objective and uses all the information in the spectrogram. As such, it is a candidate to replace and/or supplement visual spectrogram comparison and multivariate analysis as the technique of choice for comparing sounds. With the increasing availability of sound analysis software with built-in cross-correlation routines, the procedure is becoming readily available to biologists who may not have extensive knowledge of acoustics. This ease of access increases the potential for misapplication of the technique or misinterpretation of results. To assess the utility of SPCC and to highlight pitfalls that need to be avoided in its implementation, we performed a series of tests designed to reveal the sensitivity of the peak cross-correlation coefficient to a variety of...

Towards an ornithology of the himalayas: systematics, ecology and vocalizations of nepal birds

Abstract: (1997). TOWARDS AN ORNITHOLOGY OF THE HIMALAYAS: SYSTEMATICS, ECOLOGY AND VOCALIZATIONS OF NEPAL BIRDS. Bioacoustics: Vol. 8, No. 3-4, pp. 319-320.

Sound localisation in a habitat: an analytical approach to quantifying the degradation of directional cues

Abstract: Although much research has been done to describe the degradation of sound signals propagating in natural habitats, the directional cues of sound have so far been neglected. This paper describes a first approach to quantifying the degradation of directional cues in sound propagating parallel to the ground in a grassland habitat of orthopteran insects. A matched pair of probe microphones measured the sound amplitude and phase close to the ears of grasshopper carcasses for 12 evenly spaced directions of sound incidence. The degradation was found to increase with frequency and distance from the sound source and to decrease with distance from the ground. The acoustical data were used to predict how well animals with different auditory systems can determine the direction of the sender. At one position in the habitat, the predictions were compared with the pattern of phonotactic responses of live grasshoppers. Amplitude cues appear to degrade much faster with distance than phase cues. Animals exploiting...

Characteristics of the vocalizations of red deer cervus elaphus hinds and calves

Abstract: The voices of 8 hinds and their 7 offspring were analysed spectrographically. They were transformed into sonograms and the following parameters were measured: duration, fundamental frequency and frequency bands with high amplitudes. The animals emitted single calls or a series of sounds at irregular intervals. The single calls were monosyllabic and the series were homotypical sequences. The hind voices were deep and bleatlike, ranging in frequency from 70 to 3000 Hz. The fundamental frequency was 108.35 ± 15.21 Hz and the duration was 0.27 ±0.14 sec. There were 1 to 8 frequency bands with high amplitudes created. Differences between individual voices were found in all characteristics of vocalization tested. The variation between voices was a result of the combination of these characteristics. The most important factor seemed to be the pattern of main frequency bands with high amplitudes. The calf voices were high, whiny and tonal, ranging in frequency from 320 to 7000 Hz. The fundamental frequenc...

Electrophysiological Measures of Auditory Processing in Odontocetes

Abstract: The cetaceans, most notably the small odontocetes, possess extraordinary auditory faculties, remarkable in both their frequency as well as temporal capabilities. As has been abundantly documented in this volume and elsewhere, cetaceans make extensive use of sound in echolocation as well as communication behaviors. The cetaceans exhibit extremely broadband frequency sensitivity with hearing extending from below 100Hz (possibly less than 10Hz in the great whales) to greater than 150 kHz. Moreover, the smaller toothed whales in particular appear to combine high temporal resolution with very sharp frequency tuning.

Phonotaxis in the cicadas cystosoma saundersii and cyclochila australasiae

Abstract: 1. Phonotaxis was investigated in two cicada species: Cystosoma saundersii and Cyclochila australasiae. Females were placed on a stick within a flight cage and presented with artificially generated calling songs. These model calling songs had a range of carrier frequencies, but their temporal parameters were similar to those of the natural calling song. They were broadcast at intensities 30 to 40 dB above the physiological threshold for each frequency. 2. Phonotaxis of female Cystosoma saundersii was restricted to a 45 minute period just after sunset, and was highly directional. Between 60 and 70% of flights made during trials in which a model calling song was broadcast were directed towards the loudspeaker at both frequencies tested. 3. Phonotaxis of female Cyclochila australasiae occurred throughout the evening, and showed no directional preference toward the loudspeaker. The mean number of flights per trial period was significantly greater in trials during which a model calling song was broadc...

Who are the whales

Abstract: Whales, dolphins and porpoises, 80 species of entirely aquatic mammals, constitute the order Cetacea. In the early Eocene, about 55 to 60 million years ago according to paleontologists, distant ancestors of modern cetaceans left land for aquatic life. Cetaceans are diverse; average adult size of cetacean species varies by 1000 to 2000 times. Small and large species occupy all oceans from the equator to the polar seas, some forms inhabit rivers and four species live only in fresh water. Cetaceans are born in water and spend their entire lives in the aquatic medium. There is a great gap in knowledge about hearing in most cetacean species and especially about how noise and high-intensity sound may affect all cetaceans and other mammals underwater. Studies of temporary threshold shift (TTS) and occupational noise exposure in human divers suggest a cautious approach to cetacean noise exposure until data on cetacean TTS can give us some idea of the dynamic range of cetacean ears.

Stridulatory organ and ultrasonic emission in certain species of ponerine ants (genus: ectatomma and pachycondyla, hymenoptera, formicidae)

Abstract: Five species of neotropical Ponerinae ants, Ectatomma permagnum Forel, E. quadridens Fabr., E. ruidum Roger, E. tuberculatum Olivier and Pachycondyla apicalis Latreille, were studied. The genus Ectatomma, consisting of 14 species in the tropical forests of Central and South America, has been studied previously in relation to the stridulatory organ only. Stridulations were heard, in the four species considered in this paper, during artificial disturbance of individuals or of the whole colony; so the role of sound production during normal life is still uncertain. Pachycondyla apicalis, belonging to Central American forests, is occasionally present in cocoa and coffee plantations. The recordings made under laboratory conditions revealed the emission of pulse trains with very clear pulses extending in frequency to more than 75 kHz. The sounds recorded from the workers of the genus Ectatomma appeared homogeneous in their acoustic structure. They were typically emitted in long sequences and were made o...

Cetacean auditory psychophysics

Abstract: The dolphin continues to capture the imagination of investigators because of its ability to echolocate. Echolocation is essentially a special extension and adaptation of the dolphin's hearing system, coupled with the animal's ability to generate special sounds. Humans have demonstrated the ability to judge room size based on reverberation from a voice, and some of the visually challenged use self-generated sounds to detect large reflective objects. Echolocation represents a highly refined acoustic ability on a broad acoustic sensory continuum. Research on the auditory and echolocation performance of cetaceans has moved forward slowly due to limited animal resources and the general high cost of maintaining these animals in a laboratory environment. This paper reviews some of the more relevant psychoacoustic data on cetaceans, and concentrates on the bottlenose dolphin Tursiops truncatus. The information presented is not at all exhaustive. Early work with dolphins focused mainly on the animal's abi...

Do the siberian tits parus cinctus in scandinavia and siberia speak the same language

Abstract: The vocabulary of Siberian tits Parus cinctus in South Norway and East Siberia is compared by means of tape recordings and spectrograms. The species has many different calls that are greatly confused in the literature. In this paper ten main call types are examined. On the whole, the equivalent utterings are geographically so similar that a distinction is usually impossible or questionable. This similarity also applies to the contextual use of the calls. Consistent structural differences in certain calls were nevertheless found. The sit foraging call embraced on average a broader frequency range and was of a slightly longer duration in Siberia than in Norway. The complex ‘gargle’ system could at both places be divided into three main groups equally represented in the populations: (1) trilled, (2) tonal and (3) simple gargles. The tonal gargles are characterized by a terminal tonal element (T) that varies in shape. In Norway, tonal gargles terminating with an even or upslurred T dominated, in Sibe...

Questions in cetacean bioacoustics: some suggestions for future research

Abstract: This paper provides our views on the areas of cetacean bioacoustics that are in the greatest need of study over the next several years. In doing this, we ask a number of questions we see as important to developing a better understanding of cetacean bioacoustics. The topics we will cover are: Auditory Capabilities, including hearing sensitivity, pathways of sound to the ear, intraspecific variation in hearing capabilities, and the effects of intense sound on hearing capabilities; Echolocation, including the information-bearing parameters exploited by dolphin sonar systems to discriminate and identify objects, and the functional characteristics of the internal representation generated by reflections from ensonified objects; and Acoustic Communication, including the nature of the cetacean sound generation mechanism, the behaviors associated with mysticete communication sounds, and the range over which mysticetes communicate. While other investigators may not fully agree with our suggestions as to wh...

A unique local call in the willow tit parus montanos

Abstract: A unique up-slurred call of the willow tit Parus montanus, rendered pui or plui, was discovered at a locality in the birch alpine region of central Norway in the summer of 1987 when three neighbouring pairs shared this call. Up to 1996 inclusive an additional number of 19 pui-calling individuals were found. Typically, these birds were either offspring of birds already uttering the call, or members of winter flocks in which the dominant adults possessed the call. The call is evidently acquired by learning and serves as an alternative alarm call. It is suggested that rudimentary pui-calls are a normal component in babbling series of young willow tits in general and that the development of these into full calls depends on appropriate tutors. It should be emphasized that the pui-call does not replace another call in the repertoire, but is an extra call adding to the repertoire. It is probably the first time that such a phenomenon has been reported in birds. The expectation that the call would spread ...