In search of receptive females, the males of many corduliids patrol over open water. Additionally, some species exhibit localized patrol flights also over terrestrial sites. In open fen habitats, Somatochlora flavomaculata may be an extreme case in this respect as it conspicuously patrols often away from water. In consideration of its possible function the terrestrial patrol flights were investigated in a descriptive and experimental field study and compared with those at aquatic sites. Typically, the males patrolled close to vertical structures such as trees and bushes or over footpaths in glades of reedbeds. No relevant differences between the patrol fligths at aquatic and terrestrial localities were found. Both types of flight were territorial in function as conspecific males were vigorously driven away. It is speculated that the males establish territories away from ponds because the occurrence of females is unpredictable, the preferred ovipostion sites (shallow and largely overgrown puddles) being scattered over large areas. Hence, the best strategy for males for intercepting mates would be to patrol near vertical structures serving as landmarks and guidelines for arriving females.