An article in The Guardian last weekend discussed the Convention in Trade and Endangered Species (Cites) meeting in Bangkok. It mentioned a few species that had already succumbed to extinction, which included the New Zealand laughing owl. Unfortunately a trawl around the net informed me that the last sighting was in the early 20th century, and that it was unlikely that I would find a recording, even on great sites like this and this.
One episode of the beautiful BBC series Nature’s Microworlds featured the Caledonian Capercaillie, which has a really interesting call and is currently severely threatened with extinction. The Guardian also had a gallery of other extinct birds, which you can see here.
As I have already mentioned, I place great value on the work of field recordists, but I also have a great respect for bird watchers/listeners, whether or not they record their sightings. Luckily, brilliant projects like the Great Backyard Bird Survey show that numbers of some species are increasing, and gives advice to amateur ornithologists on getting involved.