He found a flock of 106 of these birds in the air together. Now, 106 Ravens in a single flock isn't astronomical. I've seen similar numbers there a time or two. It's what they were doing that was astronomical.
Now most birders know that birds regularly fly long distances at night while navigating by the stars. But how did they learn to do this? Well Craig has happened upon the answer.
You might think that they would have these lessons at night. But of course, they can't see each other then because they're black. So they have to do them during the day. In Craig's photo they're still learning of course. They don't have the pointer stars (pointing at the north star) quite right, and they may not know about the double star in the middle of the handle. But the season is still early and there's plenty of time to learn more.