Observation of Eurasian Otter’s Diel Activity Using Camera Trapping in Central-Eastern Romania

Abstract The observation of elusive mammals, is still problematic, particularly in flowing waters or wetlands. But with the usage of camera traps, it was possible to obtain valuable information about otters. The aim of this study was finding the diel activity of the otters that live in Central-Eastern Romania. The diel activity of the Eurasian otter along its habitat was studied from March 2011 to April 2016 over 1356 days & nights of camera trapping. The camera traps have recorded a total of 222 otter visits at all 10 observation sites. Otters, passing through the observation sites, were strongly nocturnal and displayed a trimodal diel activity pattern, one occurring just before dawn (between 04:00 and 06:30 h), the second one occuring just after dusk (between 18:30 and 22:00 h) and the third one occurring in the middle of the night (between 00:30 and 01:30). Otters have been also active during the Civil Twilight (7.2 %), more active during the dusk (5 %) than during the dawn (2.3 %). Seasonally the Eurasian otters were more active during winter (39.6 %) and progressively less active in spring (31.5 %) summer (9 %) or autumn (19.8 %).