Authors: Vincenzo Penteriani María del Mar Delgado Anna Kuparinen Pertti Saurola Jari Valkama Eino Salo Jere Toivola Adrian Aebischer Raphaël Arlettaz
Publish Date: 2014/02/07
Volume: 68, Issue: 5, Pages: 743-747
Abstract
Upon leaving their natal area dispersers are confronted with unknown terrains Speciesspecific perceptual ranges ie the maximum distance from which an individual can perceive landscape features play a crucial role in spatial movement decisions during such wanderings In nocturnal animals that rely on vision perceptual range is dramatically enhanced during moonlight compared to moonless conditions This increase of the perceptual range is an overlooked element that may be responsible for the successful crossing of unfamiliar areas during dispersal The information gathered from 143 radiotagged eagle owl Bubo bubo juveniles in Spain Finland and Switzerland shows that although the decision to initiate dispersal is mainly an endogenous phenomenon determined by the attainment of a given age ∼6 months dispersers leave their birthplace primarily under the best light conditions at night ie when most of the lunar disc is illuminated This sheds new light into the mechanisms that may trigger dispersal from parental territoryA special thanks to an anonymous referee and Hannu Pietiäinen who helped us to improve the manuscript and Heikki Lokki and Jyrki Savolainen who helped during fieldwork The Spanish Ministry of Economy and Competitiveness CGL2012–33240 FEDER cofinancing Junta de Andalucía Excellence Project RNM5090 and Swiss MAVA Foundation funded this study MD and AK received postdoctoral grants nos 140367 and 132828 from the Academy of FinlandWe manipulated and marked owls under 1 Spanish Junta de AndalucíaConsejería de Medio Ambiente authorizations no SCFFSAFR/GGG RS260/02 and SCFFSAFR/CMM RS1904/02 2 Finnish regional Centres for Economic Development Transport and Environment and 3 Swiss Federal Office for the Environment
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