Investigation of the context of humpback whale non-song calls in the North Atlantic

Humpback whales display behavioural plasticity in their foraging behaviours and non-song calling behaviours. Prey type appears to be associated with some of the variation in foraging behaviours and, thus, may also be related to variation in use of non-song calls related to foraging. Our goal was to compare non-song calls from two regions and identify any call types that occur in only one of the regions. We used recordings from stationary hydrophones within two foraging grounds: from the northeast Newfoundland coast, where capelin is the main prey; and the Gulf of Maine, where herring and sand lance dominate the diet. These areas are sympatric and foraging groups are thought to be from the same breeding aggregation, suggesting that call type differences would not have a genetic-basis. Most of the call types were the same across both areas, as has been found across many foraging grounds, but a small number of call types and call sequences were heard in only one of the two regions. We hope to use multi-sensor tag data and video recordings to help identify the contexts of these calls to further determine whether non-song call variation can be linked to prey type.