Proximity loggers on amphibious mammals: a new method to study social relations in their terrestrial habitat

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 Galapagos 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 spa- tial 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.

[1]  F. Trillmich,et al.  Kin in space: social viscosity in a spatially and genetically substructured network , 2008, Proceedings of the Royal Society B: Biological Sciences.

[2]  H. L. Pratt,et al.  Identifying shark mating behaviour using three-dimensional acceleration loggers , 2010 .

[3]  C. Nielsen,et al.  Effects of Joint Space Use and Group Membership on Contact Rates Among White-Tailed Deer , 2007 .

[4]  F. Trillmich,et al.  Ontogeny of Diving Behaviour in the Galápagos Fur Seal , 1997 .

[5]  D. Costa,et al.  Mobile receivers: releasing the mooring to ‘see’ where fish go , 2013, Environmental Biology of Fishes.

[6]  Hal Whitehead,et al.  Analyzing Animal Societies: Quantitative Methods for Vertebrate Social Analysis , 2008 .

[7]  Michael R. Hutchings,et al.  Use of proximity loggers and network analysis to quantify social interactions in free-ranging wild rabbit populations , 2011 .

[8]  Monika Böhm,et al.  Dynamic interactions among badgers: implications for sociality and disease transmission. , 2008, The Journal of animal ecology.

[9]  I. Staniland.  Sexual Segregation in Vertebrates: Sexual segregation in seals , 2005 .

[10]  G. Kauermann,et al.  Males in the shade: habitat use and sexual segregation in the Galápagos sea lion (Zalophus californianus wollebaeki) , 2005, Behavioral Ecology and Sociobiology.

[11]  W. Au,et al.  Rolling Stones and Stable Homes: Social Structure, Habitat Diversity and Population Genetics of the Hawaiian Spinner Dolphin (stenella Longirostris) , 2010 .

[12]  S. Gehrt,et al.  New Radiocollars for the Detection of Proximity among Individuals , 2006 .

[13]  P. White,et al.  Spatial and temporal heterogeneities in the contact behaviour of rabbits , 2011, Behavioral Ecology and Sociobiology.

[14]  P. Redman,et al.  Philopatry, Site Fidelity and Local Kin Associations within Grey Seal Breeding Colonies , 2000 .

[15]  G. J. Bishop-Hurley,et al.  Using contact logging devices to explore animal affiliations: Quantifying cow–calf interactions , 2007 .

[16]  D. Boness,et al.  Fostering Behavior and the Effect of Female Density in Hawaiian Monk Seals, Monachus schauinslandi , 1998 .

[17]  Horst Bornemann,et al.  Fine-scale feeding behavior of Weddell seals revealed by a mandible accelerometer , 2010 .

[18]  P. White,et al.  Contact rates between possums revealed by proximity data loggers , 2005 .

[19]  Russel D. Andrews.  Remotely releasable instruments for monitoring the foraging behaviour of pinnipeds , 1998 .

[20]  R. Trivers.  Parent-Offspring Conflict , 1974 .

[21]  Monika Böhm,et al.  Contact Networks in a Wildlife-Livestock Host Community: Identifying High-Risk Individuals in the Transmission of Bovine TB among Badgers and Cattle , 2009, PloS one.

[22]  Gary C. White,et al.  Accessing accuracy of a radiotelemetry system for estimating animal locations , 1985 .

[23]  I. Jonsen,et al.  Animal-Borne Acoustic Transceivers Reveal Patterns of at-Sea Associations in an Upper-Trophic Level Predator , 2012, PloS one.

[24]  Brian Otis,et al.  A novel digital telemetry system for tracking wild animals: a field test for studying mate choice in a lekking tropical bird , 2012 .

[25]  Patrick J Butler,et al.  Biotelemetry: a mechanistic approach to ecology. , 2004, Trends in ecology & evolution.

[26]  D. Costa,et al.  Age, body mass and environmental variation shape the foraging ontogeny of Galapagos sea lions , 2012 .

[27]  Peter I. Corke,et al.  Monitoring Animal Behaviour and Environmental Interactions Using Wireless Sensor Networks, GPS Collars and Satellite Remote Sensing , 2009, Sensors.

[28]  Menna E. Jones,et al.  Contact networks in a wild Tasmanian devil (Sarcophilus harrisii) population: using social network analysis to reveal seasonal variability in social behaviour and its implications for transmission of devil facial tumour disease. , 2009, Ecology letters.

[29]  Stuart Bearhop,et al.  Performance of Proximity Loggers in Recording Intra- and Inter-Species Interactions: A Laboratory and Field-Based Validation Study , 2012, PloS one.

[30]  Richard James,et al.  Automated mapping of social networks in wild birds , 2012, Current Biology.

[31]  C. Garroway,et al.  Nonrandom association patterns at northern long- eared bat maternity roosts , 2007 .

[32]  P. McLoughlin,et al.  Sex-based differences in density-dependent sociality: an experiment with a gregarious ungulate. , 2012, Ecology.

[33]  Hal Whitehead,et al.  Culture in whales and dolphins , 2001, Behavioral and Brain Sciences.

[34]  Michael C. Hansen,et al.  Accuracy, Precision, and Observation Rates of Global Positioning System Telemetry Collars , 2008 .

[35]  Steven J. Cooke,et al.  Ocean Tracking Network Canada: A Network Approach to Addressing Critical Issues in Fisheries and Resource Management with Implications for Ocean Governance , 2011 .

[36]  Richard James,et al.  Social structure in a colonial mammal: unravelling hidden structural layers and their foundations by network analysis , 2007, Animal Behaviour.

[37]  D. Lusseau,et al.  Animal social networks: an introduction , 2009, Behavioral Ecology and Sociobiology.

[38]  Christopher O. Kochanny,et al.  GPS radiotelemetry error and bias in mountainous terrain , 2002 .

[39]  F. Trillmich,et al.  Male reproductive success and its behavioural correlates in a polygynous mammal, the Galápagos sea lion (Zalophus wollebaeki) , 2010, Molecular ecology.