Dear colleagues, we are pleased to announce the publication of our paper:
Meise K, Krüger O, Piedrahita P, Müller A, Trillmich F (2013). "Proximity loggers on amphibious mammals: a new method to study social relations in their terrestrial habitat." Aquatic Biology 18: 81-89 ABSTRACT. Amphibious mammal species alternate between foraging at sea and attendance on land. Due to thermoregulatory requirements, they often haul out during the night, making social interactions difficult to observe. We tested the suitability of UHF-proximity loggers for assessing social relationships among Galápagos sea lions Zalophus wollebaeki. To survive periods at sea, proximity loggers were embedded in epoxy. Automatic downloads to receiving stations rendered logger recovery unnecessary. Encounters were logged within a range of 10 m. Logs provided information about interacting individuals as well as time and duration of encounters. ‘Received signal strength indicator’ values correlated with distance, but were influenced by antenna angle and environmental factors. Laboratory tests and validation in the field demonstrated that the spatial resolution corresponded to 2 m. Data needed to be corrected, as single encounters were recorded as multiple logs and reciprocity of loggings between animals was not always achieved. Digital data correlated with observational data, but associations were 4 times more likely to be detected using proximity loggers. Data revealed that non-territorial males frequently associated for extended periods of time, especially during the night and even outside the study colony. The modified proximity logger system proves an excellent tool to determine social structure in situations where direct observation is limited. keywords: amphibious species, proximity logger, social structure The article is available at: http://www.int-res.com/abstracts/ab/v18/n1/(http://www.aquaticmammalsjournal.org) Best wishes, Kristine Meise University of Bielefeld Department of Behavioural Biology Morgenbreede 45 33615 Bielefeld, Germany + 49 521 106 2193
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