MoreBeach.com

February 3, 2009 - Whale acoustics researcher Mark McDonald was trying to track blue whales' movements using data from Navy submarine detectors. He had created a program to filter out the blues' songs from other noise. But he kept having to rewrite the code. Each year, it seemed, the whales sang at a lower pitch. No one knows why. One conjecture is that more baritone whales indicate healthier populations: The whales may be less shrill because they're less scarce and don't have to pipe up to be heard by neighbors. Here's the full story from Jill Leovy at LA Times blogs.

Here's a link to blue whale songs.