Acoustic communication in a king penguin colony: importance of bird location within the colony and of the body position of the listener

This study focuses on the propagation of the display call used for individu al recognition between penguin partners. Transmission of acoustic informati on in a noisy environment such as a king penguin colony is very difficult. Conditions of propagation were examined for two areas of the colony (hatchi ng and courtship areas) and reception at three heights from the ground (10, 45 and 90 cm). Signal modification was assessed in terms of attenuation of signal, amplitude modulation and spectral content. The acoustic recognitio n of the mate, which is decisive for breeding success, took place in the ha tching area where signal degradation was less great for all parameters stud ied. When the receiver was located 10 cm above the ground, degradation of t he signal was much more pronounced than when it was located 45 or 90 cm abo ve ground. The characteristic incubating altitude of the king penguin (i.e. standing with the head at 45 cm above the ground) enables it to receive th e main part of the signal in spite of the noisy environment.