Baird Robin W.

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Baird
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Robin W.
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  • Article
    Whistle characteristics and daytime dive behavior in pantropical spotted dolphins (Stenella attenuata) in Hawai‘i measured using digital acoustic recording tags (DTAGs)
    (Acoustical Society of America, 2016-07-19) Silva, Tammy L. ; Mooney, T. Aran ; Sayigh, Laela S. ; Tyack, Peter L. ; Baird, Robin W. ; Oswald, Julie N.
    This study characterizes daytime acoustic and dive behavior of pantropical spotted dolphins (Stenella attenuata) in Hawai‘i using 14.58 h of data collected from five deployments of digital acoustic recording tags (DTAG3) in 2013. For each tagged animal, the number of whistles, foraging buzzes, dive profiles, and dive statistics were calculated. Start, end, minimum, and maximum frequencies, number of inflection points and duration were measured from 746 whistles. Whistles ranged in frequency from 9.7 ± 2.8 to 19.8 ± 4.2 kHz, had a mean duration of 0.7 ± 0.5 s and a mean of 1.2 ± 1.2 inflection points. Thirteen foraging buzzes were recorded across all tags. Mean dive depth and duration were 16 ± 9 m and 1.9 ± 1.0 min, respectively. Tagged animals spent the majority of time in the upper 10 m (76.9% ± 16.1%) of the water column. Both whistle frequency characteristics and dive statistics measured here were similar to previously reported values for spotted dolphins in Hawai‘i. Shallow, short dive profiles combined with few foraging buzzes provide evidence that little spotted dolphin feeding behavior occurs during daytime hours. This work represents one of the first successful DTAG3 studies of small pelagic delphinids, providing rare insights into baseline bioacoustics and dive behavior.
  • Preprint
    Successful suction-cup tagging of a small delphinid species, Stenella attenuata : insights into whistle characteristics
    ( 2016-09) Silva, Tammy L. ; Mooney, T. Aran ; Sayigh, Laela S. ; Baird, Robin W. ; Tyack, Peter L.
    The Delphinidae is the most diverse family of cetaceans, with 38 species recognized. Small pelagic delphinids are also the most abundant cetaceans world-wide, yet their communication and behavior remain poorly understood. Many populations live in relatively remote habitats, which creates challenges in accessing study animals. Small odontocete species often face numerous anthropogenic stressors. For example, many pelagic delphinids incur significant interactions with fisheries (Gerrodette and Forcada 2005, Geijer and Read 2013). With a wide distribution, many delphinid populations utilize habitats that also are important for human seagoing activities that produce intense sound, such as seismic surveys or naval sonar exercises that may disturb or harm them. Many U.S. naval sonar exercises take place on naval training ranges such as those in in Hawai‘i (Baird et al. 2013), California (Carretta et al. 1995, Henderson et al. 2014), and the Bahamas (DeRuiter et al. 2013). At least one delphinid stranding event involving melon-headed whales (Peponocephala electra) was correlated with military activities (Southall et al. 2006); a mass stranding of melon-headed whales has also been associated with multi-beam echosounder operations as part of a seismic survey (Southall et al. 2013). Because many of these delphinid groups can number in the 100s to 1,000s, fisheries or sonar exposures can account for the highest estimates of marine mammal “takes” in related Environmental Impact Assessments (Department of the Navy 2013). Given the potential for anthropogenic interactions with large numbers of individual delphinids, improved methods of studying small delphinids are invaluable to understand, reduce, or mitigate potential human influences on these animals.