08 Nov 2017
Abundance of cetaceans in the European Atlantic: results from SCANS-III aerial and ship surveys in 2016. - Phil Hammond, SMRU
Seminar Room, The Observatory: 1:00 PM, 08 Nov 2017
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Seminar Room, The Observatory: 2:00 PM, 22 Nov 2017
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23 Nov 2017
Vocal repertoires of two matrilineal social whale species Long-finned Pilot whales (Globicephala melas) & Killer whales (Orcinus orca) in northern Norway
LTD, Bute: 1:00 PM, 23 Nov 2017
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A vocal repertoire subset from seven groups of pilot whales and 11 groups of killer whales recorded in the Vestfjord in northern Norway during the time period 2004 until 2011 will be presented.
Using observer-based acoustic analysis 129 call types and 25 subtypes for long-finned pilot whales, and 60 call types and 25 subtypes for killer whales were classified. Per group, pilot whales used an average of 36 call types and killer whales 25. The general structure of call types was similar, with most call types consisting of one segment and two elements with different structures. The main element structure in pilot whale and killer whale calls was an ascending frequency band. The amount of two-voiced calls was 29% for pilot whales and 47% for killer whales. In addition, there were different call type combinations and repetitions and ultrasonic whistles, already known in killer whales, but newly described for pilot whales in this study.
The main difference between vocal repertoires of the two species appeared at the call type sharing between the groups. Pilot whales only shared 28% of their call types and 37% of their total calls with at least one other group, whereas killer whales shared 59% of their call types and 90% of their total calls. In 2011 a new foraging method for salmon by killer whales in Norway was discovered and for the first time it was possible to observe the same two groups of killer whales for three and six months and describe a full repertoire with 59 call types and 25 subtypes. It was not possible to completely separate the calling of the two groups, but nevertheless it shows that the vocal repertoire is larger than earlier described. In addition, context-specific vocalisations were detected during salmon feeding and non-feeding contexts, and compared to herring feeding and a food association call from the Icelandic killer whale population. Specifically, certain call type combinations contained the same beginning part in all feeding contexts, but the combinations differed for salmon and herring feeding and between groups. These differences will be discussed in the light of possible referential and/or arousal calling in association with food in killer whales.
LTD, BSRC: 1:00 PM, 07 Dec 2017
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