The New York Times featured an about whales online (7 January 2019): https://www.nytimes.com/2019/01/07/science/whales-songs-acoustics.html
The lead photo is one of mine. The whale in the photo wasn't singing, even though much of the article discusses whale song.
In short, despite who knows how many combined hours of observation, recording and thinking about whale song, we basically don’t know what’s going on.
For anyone who spends enough time in nature, this will come as no surprise. It’s easy to get the mis-impression from watching documentaries and such that we know a lot.
While we’ve definitely made lots of progress and continue to do so in terms of our knowledge of the world around us, it’s good to keep proper perspective. We’ve got a lot to learn!