Continuing with the theme of ravens, I'd thought I'd quickly point out this pretty cool video of a crow snowboarding down a roof using a small disc it found. When it gets to the bottom, the crow goes back up and does it again. This reminds me of the New Zealand orcas which have learned to surf the waves there. Hopefully, the crow teaches this to its young.
On an only tangentially related note, I'm still trying to decide if this is the use of a tool or not. If so, it's a major win for dogs.