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 bas: of the digitised spectrograms. Special attention is given to the use of smoothin algorithms and dynamic thresholds in order to estimate sound features and to reduc influences resulting from recording conditions. The suitability of our approach has bee demonstrated successfully for vocalisations of different species.