If you didn't catch the NPR report on crows earlier this week, I recommend you listen to it now. Fascinating stuff. When you go to the NPR page, consider watching the video feature near the top that summarizes a crow's interesting ability to recognize human faces or listen to the full radio broadcast (just a mere 7 minutes and 49 seconds near the bottom of the post). Or, you can see if you can recognize a crow's face with the quiz in the middle. (I did pretty well at my first and second try and then started failing miserably.)
This is very interesting...so much so that others (like Joshua Klein) have picked up on crows' abilities and have begun to think about the possibilities in training them.
If you have never been to home site of ted.com where Joshua Klein's presentation is posted, spend some time there. You can learn and learn and learn. Listen and watch, spit out what you don't like, and really chew on the rest.