If you ignore him or her, he or she will ignore you.
If you go outside, and the crow or crows fly away, they weren't talking to you.
If they stay, but are somewhat at a distance, they may be merely amused or checking you out from your appearance into their "space" - of that moment - and intrusion into their conversation.
If they fly closer to you, and tease you with "silence" they are "listening" to you.
If they fly close and chatter one way or another, especially looking your way, or do strange or unusual actions in front of you to get your attention they are telling you something.