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The paper gives an overview of the capacities of the software solutions for a sound analysis system based on the program development environment LabVIEW and shows some applications of the system by using suckling grunts of domestic pigs Sus scrofa as an example.
LabVIEW represents a versatile tool for the development of sound analysis software including sound processing and sound statistics. Particularly, the increasing need for flexible numerical processing of different acoustic parameters can be considered. The graphical object -oriented language allows programming without special experience because it uses terminology, icons and theories familiar to scientists and engineers. LabVIEW is available for Macintosh, Sun, HP-UX, Windows 95, Windows NT, Windows 3.1., and can also be used as a teaching tool to gain technical knowledge of signal analysis and signal processing.
                Paralleled by behavioural observations, the bioacoustical studies of animals at various levels, including the incorporation of techniques that are used in animal communication, human speech recognition or in technical acoustics, are able to reveal the specific meaning of vocalisations. Based on the example of the analysis of suckling grunts of domestic pigs the impact of an application of the system developed in our group is demonstrated.

We introduce an inexpensive electronic technique for monitoring the temporal aspects of any captive animal's acoustic signals. The electronic apparatus, attached to a data acquisition unit and personal computer, compares microphone output to a pre-set level and stores calling/non-calling data to disk. Total time calling and temporal signaling patterns of up to 256 individuals can be monitored for indefinite lengths of time. Sampling rate is adjustable, with a maximum rate of 6 samples/microphone/second. The capabilities of the system are illustrated with the field cricket Gryllus integer. Temporal aspects of acoustic signaling are discussed in terms of monitoring time scale and recognition of individual variation, energetics research, and hypothesis testing of the costs and benefit,: associated with mating success and predation.

The theory of communication networks offers functional arguments for the evolution of unobtrusive signals in birds. The vulnerability of interacting conspecifics to predation and to eavesdropping by neighbours during both territorial disputes and courtship would select for short range signals such as the quiet songs of birds. In addition to suggesting contexts in which quiet songs should be used, we use our knowledge of the physics of sound transmission to make predictions about the physical structure of such songs relative to the well studied full songs. We present support for these predictions in six species where quiet singing has been observed.

We describe the vocal repertoire of the Asian cricket frog Rana nicobariensis for the first time. Three structurally-distinct call types exist: advertisement calls, aggressive calls and encounter calls. Compound calls consisting of both advertisement and aggressive elements were also recorded. A remarkable feature of communication in this species is the highly variable advertisement call which shows a 20-fold variation in duration, comprising 1-25 notes. In natural choruses, the duration of the advertisement call is inversely related to the distance between a focal male and its closest calling neighbour. In playback experiments, males clearly responded to stimuli containing different numbers of notes by adjusting the number of notes emitted. However, they did not match the stimulus precisely, and were inhibited from calling by a stimulus consisting of a continuous train of notes. Different proportions of each call type were recorded during playbacks at different distances; aggressive and encounter calls were increasingly emitted at closer distances. Our results suggest that a graded communication system has evolved in Rana nicobariensis, in which the best call for a male to use at any moment depends on the type of calls being emitted by other males in the chorus.

An acoustic signal is altered by various processes during long-range propagation. Birds may use degraded sound features to assess the distance of the emitter. To know which temporal sound features are susceptible to be used by birds for ranging, we performed a study using natural and synthetic acoustic signals which had different temporal sound degraded characteristics, i.e amplitude and frequency modulations and sound-silence alternations.

Our data show that the degradation of some temporal features may give ranging information, especially in a forest environment. Indeed, in an open field, the assessment of an emitter's distance using sound temporal features may be rather difficult since there is no modification of sound/silence alternation, frequency-modulated notes are preserved, and fluctuations of amplitude are at random, except for high-pitched sounds. In contrast, forest birds may rely on different parameters for ranging, since in this environment duration of notes, degradation of frequency modulation as well as degradation of amplitude modulation of high-pitched notes are linked with propagation distance.

Blue tits, as many other species, show much geographic variation in their songs. In blue tits, songs that include a trill (series of rapidly repeated notes) are widespread on the European mainland, but have not been reported in North Africa or the Canary Islands. We studied song structure of two blue tit populations from the French Mediterranean that are exposed to large differences in local selection pressures (food, vegetation, social factors). Songs from populations on the European mainland and the island of Corsica differed much in syntax, tempo, frequency, and the incidence of trills. The observed population differences could potentially be caused by a combination of different factors, including biotic and abiotic habitat characteristics, body size, and cultural drift. We suggest that songs without trill are acoustically adapted for transmission in habitats where the local breeding density of great tits is low. In addition, we suggest that songs with trill may reject a character shift to minimise territorial interactions with great tits.