Whistles, clicks, and calls
'Residents' and offshores are very vocal, Bigg's (transients) very quiet and stealthy.
We make recordings in the field along with behavioral observations, and we also have year round autonomous hydrophones that detect presence of certain pods, which is helpful because its very difficult to do field work in the winter.
Dialects: Each family of residents (salmon specialists) has their own calls, making it easy to know where each pod spends time in different parts of the year, including winter. Calls are passed down through the generations, so new calves learn family calls from their mothers (who learned them from grandmothers). When a pod grows and splits, the calls of the cousins remain similar, but distinct from each other. It is believed that residents mate with the 'sexy foreign accent.'