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Abstract and Summary

Observation of ibex (Capra pyrenaica) in Cazorla and Segura (South-eastern Spain) revealed a negative relationship when group size was plotted against individual time dedicated to vigilance and a positive one when plotted against time used for feeding. Generally, adults of both sexes were more vigilant than juveniles and more vigilance occurred in the morning than in the afternoon and evening combined. Peripheral animals were more vigilant than central ones.

The relationship between group size and vigilance rate shows that when mixed groups become large, and correspondingly when the level of interactions is frequent, the negative relationship observed between small group size and rate of vigilance is broken. This occurs during the rut, when the importance of the animals as look-out also decreases if they are located at the periphery of the group, due to an increase in the interest in activities related to reproduction.

Zusammenfassung

Beim Iberiensteinbock in Südostspanien nimmt mit der Truppgroße die Wachsamkeit der Individuen ab, ihre Freßdauer zu. Erwachsene beiderlei Geschlechts sind wachsamer als Junge, und alle sind morgens länger wachsam als nachmittags und abends. Individuen am Gruppenrand sind wachsamer als die im Gruppenzentrum.

In ganz großen gemischten Gruppen während der Paarungszeit folgt die Wachsamkeit diesen Regeln nicht. Dann ist die Aufmerksamkeit mehr auf die vielen Interaktionen in der Gruppe gerichtet.