They also do this to cats, which is much more dangerous. There's a video with a cat catching a bird (not a crow) that did this: https://youtube.com/watch?v=nfIQifAcm0g
In that case, yes. It was just to illustrate that cats are eerily effective at catching birds mid-flight.
But I have seen a cat trotting along a wire fence with a concrete base. On that base, which was about the cat's height there was a hooded crow happily scuttering behind the cat and grabbing at its tail from time to time.
The cat mostly ignored it but it was apparent that it judges the chances of catching the pesky bird.
