The female perching behaviour in Orthetrum coerulescens, Crocothemis erythraea and Sympetrum vulgatum in high density situations can be explained by habitat and situation. In O. coerulescens 86.2% of the females perched immediately after copulation. After disturbance of the preceding copulation'and in the presence of rival males, the perching duration (PD) was longer. In C. erythraea at sites without perches all females immediately started to oviposit whereas at sites with emergent vegetation 75.8% remained perched. PD was longer in cases of male interference with the preceding copulation. In S. vulgatum after tandem oviposition at sites with emergent vegetation, 24.2% of all females settled on a perch site. This behaviour occurred more often after disturbance of the preceding tandem oviposition and in the presence of rival males. In all species PD did not change with multiple matings. Perching before the start of oviposition may serve as a tactic to evade male interference or to assess predator pressure at the oviposition site.