BIOACOUSTICSTable of Contents: Volume 10
BIOACOUSTICS
M. Ballintijn & C. ten Cate (1999). Acoustic differentiation in the coo-vocalisations of the Collared Dove. Bioacoustics 10(1): 1-17
Abstract
According to their different functional contexts and accompanying visual displays, the coos of the collared dove Streptopelia decaocto can be classified into three different types. This study examined whether these coo types also differ in acoustic characteristics. A large set of temporal, frequency and amplitude characteristics was measured to determine intra-individual variation within and between the coo types. Discriminant function analyses revealed that temporal parameters were best at discriminating between the coo types. Combined with the known variation in context and visual displays a strong case can be made that the coo types of the collared dove are likely to convey different information. Comparison of intra-individual variation within and between the coo types revealed clear differences between the acoustic parameters. The fundamental frequency, which is probably primarily determined by syrinx structure, was a very stable parameter. The amplitude of coos, which may depend on the activity of the abdominal muscles, was highly variable, but did not vary systematically between the coo types. Most temporal features were stable within a coo type, but varied significantly between coo types.
Keywords: vocalizations, differentiation, sound production, dove
I.M. King (1999). Species-specific sounds in water bugs of the genus Micronecta. Part 2, Chorusing. Bioacoustics 10(1): 19-29
Abstract
Although chorusing behaviour has been reported previously in six species of corixid water bugs, including one European species of Micronecta, no analysis of chorusing has been published for Micronecta. Studies of a large pond in SE Australia show that chorusing occurred in the most common species of Micronecta in the study area, M. concordia. Pulse-trains synchronized with those of other individuals nearby were the predominant acoustic output of M. concordia males throughout the stridulating season, from mid-winter to mid-summer. At the start of the season, chorusing began with an exponential increase in the percentage of synchronized signals over a period of six days.
Keywords: Acoustic communication, chorusing, synchronized signals, Micronecta, water bugs
I. Klit (1999). The function of song forms in the Lesser Whitethroat Sylvia curruca. Bioacoustics 10(1): 31-45
Abstract
The pattern of song activity during different stages of the breeding cycle was investigated in males of the lesser whitethroat Sylvia curruca. Males had a high song output during the prefertile period after which the song activity declined abruptly. This pattern is consistent with the song functioning in territory defence and mate attraction. Most males did not sing when their mate was fertile. It is suggested that this silence is a strategy by which the male tries to conceal the precise position of the fertile mate to avoid being cuckolded. The lesser whitethroat has two song forms': 'trill' and 'twitter'. The physical properties of these indicate that they are specialized for communication over different distances. The high amplitude trill may serve as a long-distance signal whereas the low amplitude twitter allows only short-range communication. The two song forms could also have evolved for intersexual and intersexual usage. The stereotyped trill song form was dominant relative to the twitter song form late in the breeding cycle, indicating that trill is used primarily in male-male communication. The variable twitter song form was dominant early in the breeding cycle when the males were attracting mates, indicating that twitter is used primarily in male-female communication.
Keywords: Sylvia curruca, song activity, silent strategy, long- and short distance communication, intra- and intersexual song form
J.N. Mathews, L.E. Rendall, J.C.D. Gordon & D.W. Macdonald (1999). A review of frequency and time parameters of cetacean tonal calls. Bioacoustics 10(1): 47-71
Abstract
Properties of the tonal calls of cetaceans are summarised and compared at the species level. Statistics are presented relating to start, end, minimum, maximum and centre frequencies, duration and number of inflections, together with information about recordings (location, number encounters/groups, length of recordings). Evidence of a linear relation between body-size and wavelength is given for odontocetes (R2 between 0.68 and 0.93, depending on frequency variable and least-squares method) but the relationship does not appear to fit well for mysticetes (R2 = 0.64). Results of preliminary investigations into acoustic discrimination of species by multivariate methods ate also presented: a simple classifier for 10 species based on results derived from the literature gave a correct classification rate of 28% when tested with independent data. Some methodological recommendations for future descriptive work on cetacean acoustics are made.
Keywords: cetaceans, acoustics, tonal, classification, body-size
C. Walcott, D. Evers, M. Froehler & A. Krakauer (1999). Individuality in "Yodel" calls recorded from a banded population of Common Loons, Gavia immer. Bioacoustics 10(2-3): 101-114
Abstract
Male common loons, Gavia immer, produce a territorial vocalization called the yodel. We quantitatively examined yodels using discriminant and cross correlation analysis. Both techniques correctly assigned the majority of the male's yodels to the proper group, however discriminant analysis was more accurate for making long term comparisons of a yodel's stability. Of four male loons in a color marked, breeding population at the Seney National Wildlife Refuge in Michigan, each male's yodel was different and these differences were maintained over the six years of this study. There is a suggestion that changes in the yodel may be related to territory and mate switching, indicating that individuality in the yodel may be linked to female choice.
Keywords: common loon, yodel, vocal-tagging
I.M. King (1999). Acoustic communication and mating behaviour in water bugs of the genus Micronecta. Bioacoustics 10(2-3): 115-130
Abstract
The role of male sounds in attracting females and in mating was investigated in the three most common species of Micronecta found in ponds 60 km NE of Melbourne, Australia: M. concordia, M. tasmanica and M. robusta. In playback experiments using recorded male signals, females were attracted to signals of conspecific males, in preference to signals of heterospecific sympatric males. Studies of mating behaviours using video recording, showed that signals were obligatory for mating. These findings strongly suggest that acoustic signalling is important in reproductive isolation in Micronecta. Comparisons between matings and rejected matings showed that, within each species, copulation only occurred following a certain minimum number of acoustic signals with more pulse-trains than the mean for the species. Low amplitude sounds (after signals) were also important in courtship, immediately preceding mating. No sounds occurred during copulation.
Keywords: Acoustic communication, mating, playback, Micronecta, water bugs
T. Riede & A. Stolle-Malorny (1999). The vocal change of a kitten with craniocerebellar trauma - a case study. Bioacoustics 10(2-3): 131-141
Abstract
The conspicuous vocalisations of a three-month o1d cat with craniocerebellar trauma were studied. A temporal coincidence between the improvement of the clinical condition and the change of the vocal utterances was observed. This vocal change could be observed in relevant acoustic parameters but it was seen more clearly in nonlinear phenomena (biphonation, subharmonics and deterministic chaos) in the cat's acoustic repertoire. The vocal change was also recognizable to the unaided ears.
Keywords: disease, craniocerebellar trauma, cat, nonlinear phenomena, subharmonics
J.J. Luczkovich, M.W. Sprague, S.E. Johnson & R.C. Pullinger (1999). Delimiting spawning areas of weakfish, Cynoscion regalis (family Sciaenidae), in Pamlico Sound, North Carolina using passive hydroacoustic surveys. Bioacoustics 10(2-3): 143-160
Abstract
Exact locations of spawning areas used by marine fishes are needed to design marine reserves and estimate spawning stocks. The location of spawning areas of soniferous fishes such as weakfish Cynoscion regalis can be determined by means of passive hydroacoustic surveys. We conducted nocturnal hydrophone surveys at 12 locations in Pamlico Sound in May of 1996 and 1997. Digital audio tapes were made of weakfish ''purring'' sounds, the tapes were analyzed spectrographically and compared with ichthyoplankton surveys taken at the same stations and times. All weakfish “purring” sounds were recorded at stations near inlets. Maximum sound pressure levels recorded after sunset were 127 dB (re 1 μPa) for individual weakfish, but reached a maximum of 147 dB when weakfish and other fish were producing sounds simultaneously. The maximum distance that an individual weakfish “purr”' can be detected above the background sound, assuming a cylindrical spreading model, is approximately 50 m. There was a strong association (r = 0.78) between the log10-transformed abundance of early-stage sciaenid-type eggs and maximum sound pressure levels, with the greatest numbers occurring at the inlet stations. These results suggest that passive hydroacoustic surveys can be used to delimit spawning areas for conservation and management purposes.
Keywords: Fisheries, underwater acoustics, hydrophone surveys, ichthyoplankton, sound attenuation
C. Budde (1999). The vocal repertoire of the Grey crowned crane Balearica regulorum gibbericeps. 1. The tonal and the non-harmonic calls. Bioacoustics 10(2-3): 161-173
Abstract
The study describes the vocal repertoire of the Grey Crowned Crane Balearica regulorum gibbericeps and speculates on the purpose the calls serve. The repertoire consists of 4 tonal and 7 non-harmonic calls. Chicks have 3 different vocalizations.
Keywords: vocalization, Grey Crowned Crane, Balearica regulorum, chicks
U. Kaya & A.M. Simmons (1999). Advertisement calls of the tree frogs, Hyla arborea and Hyla savignyi (Anura: Hylidae) in Turkey. Bioacoustics 10(2-3): 175-190
Abstract
The systematic classification of tree frogs (Hyla) inhabiting different regions of the country of Turkey is unclear. Recordings of natural advertisement calls of individual male tree frogs in different locations in Turkey were analyzed to determine variation in acoustic features that may be related to taxonomic status. Multivariate analysis of covariance showed that call duration, intervals interval and number of pulses per call varied significantly between frogs in different locales. Call duration, intervals interval, and number of pulses per call were related to air temperature. Dominant frequency differed significantly between different groups of frogs, and was temperature-independent. These data are consistent with the hypothesis that tree frogs in Turkey represent two distinct species, Hyla arborea and Hyla savignyi.
Keywords: tree frog, Hyla arborea, Hyla savignyi, Anura, advertisement calls
C. Budde (1999). The vocal repertoire of the Grey crowned crane Balearica regulorum gibbericeps. II. The unison call of the crowned crane. Bioacoustics 10(2-3): 191-201
Abstract
This paper presents the acoustic features and the behavioural context of the unison call of the East African Crowned Crane Balearica regulorum gibbericeps. It speculates on the different functions of the unison call according to the situations where it is given. This is tested with the appeasement-threat hypothesis, which claims that the threatening acoustic characteristics of the unison call should be enhanced if it is given as a territorial call. In comparison, the appeasing acoustic characteristics should be stronger if the unison call is performed at flock sites where it possibly serves for mate assessment.
Keywords: vocalization, Grey Crowned Crane, Balearica regulorum, unison call, captive breeding
G. Francescoli (1999). A preliminary report on the acoustic communication in Uruguayan Ctenomys (Rodentia, Octodontidae): basic sound types. Bioacoustics 10(2-3): 203-218
Abstract
Subterranean rodents are interesting organisms for communication studies because of their fossorial way of life. Acoustic communication in the South American genus Ctenomys has not yet been studied even though this species is geographically widespread. This paper represents a preliminary survey of Ctenomys vocalizations. Three types of vocal signals were identified: S-, C- and G-signals. Using field, laboratory and literature data, we provide interpretations on the possible functions of these signals. S-signals are harsh and low-pitched putative spatial localization signals that may also encode for sexual identification. C-signals are relatively high-pitched and narrow-banded FM vocalizations that are sexual signals used by females in a copulatory context. Finally, G-signals are harsh and patternless sounds that are aggressive signals used in direct encounters with eon- or hetero-specific individuals.
Keywords: Ctenomys, vocalizations, repertoire
F. Lang (2000). Acoustic communication distances of a gomphocerine grasshopper. Bioacoustics 10(4): 233-258
Abstract
I studied in the laboratory and in the field the communication distance of the gomphocerine grasshopper Chorthippus biguttulus, which lives close to the ground in stony, short grass habitats. Using sound measurements and behavioural tests, 1 examined the frequency dependent attenuation and temporal degradation of the song pattern. Sound measurements (2-40 kHz) in the field revealed that excess attenuation increases with increasing frequency. Close to the ground, excess attenuation reaches 18 dB/m. On the basis of (i) excess attenuations, (ii) tympanic receptor threshold curves and (iii) song spectra, perception distances of female tympanic receptors for male songs and vice versa were calculated. Behavioural tests revealed that, especially in short and stony grass vegetation, the typical habitat of Ch. biguttulus, the temporal song pattern is strongly degraded. Thus, in the laboratory and in tall grass vegetation, sound attenuation was found to limit the communication distance. In contrast, in short grass vegetation, degradation of the temporal pattern was found to limit the communication distance of males listening to female songs. I argue that the exploitation of fast amplitude modulations for song recognition restricts the acoustic communication of grasshoppers to short distances (1-2.2 m). In this respect it seems adaptive to stridulate at 1ow intensities.
Keywords: grasshoppers, field studies, acoustic communication distance, sound attenuation, temporal degradation
S. Sanvito & F. Galimberti (2000). Bioacoustics of southern elephant seals. I. Acoustic structure of male aggressive vocalisations. Bioacoustics 10(4): 259-285
Abstract
Southern elephant seal Mirounga leonina males have a complex and stereotyped system of access to breeding females. The single most important component of male behaviour is vocal signalling, which is used to settle agonistic encounters in most cases. Most aspects of the breeding biology of the species have been studied in depth, but detailed information about the structure of vocalisations is not readily available.
Here, we present data about the acoustic structure of aggressive male vocalisations collected in the Falkland Islands and we compare these data to published data on the northern elephant seals. Our main goal is to describe the structure of sounds as a preliminary and indispensable step towards analysis of their functional significance. Male vocalisations are low-pitched sounds, made up of pulse trains, with little frequency modulation. Low frequency and high sound pressure level are typical of male vocalisations in Pinnipedia, but they were particularly evident in southern elephant seals, probably due to the unusually large body size. The comparison with published data on northern elephant seals was not very easy, due to differences in acoustic terminology and methodology, but it revealed many similarities between the species.
We also carried out a detailed analysis of variability of different acoustic variables. We discovered that frequency and intensity measures have lower variability than temporal ones and should hence be the most effective way to convey information about the individual who emits the vocalization.
Keywords: Southern elephant seal, Mirounga leonina, vocalisations, bioacoustics, spectral analysis, agonistic behaviour, Falkland Islands.
S. Sanvito & F. Galimberti (2000). Bioacoustics of southern elephant seals. II. Individual and geographical variation in male aggressive vocalisations. Bioacoustics 10(4): 287-307
Abstract
In traditional studies of animal communication, individual variability was sometimes considered less relevant than species specific aspects, mostly because the goal was the classifications of sounds in repertories. However, individual variability seems to have a significant role in signal function and evolution. In this paper, we analyse individual variation in the structure of aggressive vocalisations of male southern elephant seals and we compare sounds from our main study population, Sea Lion Island (Falkland Islands), with sounds recorded in the nearby population of the Valdés Peninsula (Patagonia, Argentina). We firstly analysed the repeatability of acoustic parameters at vocalization and male level. Repeatability of bouts of the same vocalization was extremely high and this confirmed that vocalization is the fundamental level of organization of male acoustic communication in this species. Also repeatability of vocalisations of individual males was very high and hence sounds may effectively convey information about identity of the individual who emits the sound.
Male aggressive vocalisations were categorized into a small number of types and each male emitted always the same type of vocalization. We compared the typology of sounds emitted by Sea Lion Island males with vocalisations by Valdés Peninsula males and we found striking differences. The two populations shared none of the sound types and, although similar in fundamental acoustics, sounds from the two populations had a different macrostructure. We conclude that these two populations show dialects in male acoustic communication, although the scarcity of recordings from other populations limits the scope of this conclusion.
Keywords: Southern elephant seal, Mirounga leonina, vocalisations, bioacoustics, individual variation, geographic variation, dialects, Falkland Islands, Valdés Peninsula.
M.E dos Santos et al. (2000). Sound production by the Lusitanian Toadfish Halobatrachus didactylus. Bioacoustics 10(4): 309-321
Abstract
Several batrachoidids have been known to produce sounds associated with courtship and agonistic interactions, and their repertoires have been studied acoustically and behaviourally. In contrast, sound production of the Lusitanian toadish Halobatrachus didactylus, although often noted, has not been acoustically studied. This sedentary predator of Northeastern Atlantic coastal waters is usually found in sandy and muddy substrates, under rocks or crevices. Sound recordings were made in Ria Formosa, a lagoon complex in southern Portugal. The sound producing apparatus was studied in adult individuals of both sexes captured by local fishermen. It is shown that this species produces acoustic emissions similar to other batrachoidids. It produces a long, rhythmical, tonal sound, often in choruses, which is comparable to the boatwhistle or hum signals of Opsanus and Porichthys, and a complex of signals that were classified as grunts, croaks, double croaks and mixed calls ('grunt-croak’). As in other toadfishes, H. didactylus presents sonic muscles connected to a bi-lobed swimbladder. Asynchronous contractions of the sonic muscles were detected when massaging the ventral surface of the fish.
Keywords: toadfish, Halobatrachus didactylus, Batrachoididae, acoustic repertoire, sonic muscles.
Luczkovich, J.J. et al. (2000). Sounds of sex and death in the sea: bottlenose dolphin whistles suppress mating choruses of silver perch. Bioacoustics 10(4): 323-334
Abstract
Prey often exhibit avoidance behaviors when predators are present. We observed diminished loudness of mating choruses of male silver perch Bairdiella chrysoura in spawning areas when vocalizing bottlenose dolphins Tursiops truncatus, which hunt fish acoustically, were present. Experimental playback of bottlenose dolphin sounds revealed that male silver perch mating calls were reduced by an average of 9 dB. This “acoustical avoidance'' behavior, demonstrated previously for interactions involving bats hunting insects and frogs, may also be a common phenomenon in acoustically mediated predator-prey interactions in the sea.
Keywords: Underwater acoustics, marine mammal vocalizations, soniferous fish signals, predator avoidance, playback experiment