I like that Iisbach! =)
When you're outdoors you're bound to run into animals and insects upclose and personally. Especially when you aren't moving, animals and insects don't pay much attention that you're there. A "sign" is only when animals, insects or nature in general acts out of the ordinary or when you are asking for a message (then your mind will naturally pick up on elements that can be deciphered). .
Here is an example of something that happened to me many years ago. I asked for a sign that my ritual/prayer was heard. I sat quietly and waited. No more than 2min later, behind me I heard a sound I could not decipher. It was an animal, but nothing I had ever heard before. I couldn't determine what it was. There was no animal in sight either. A week past and I got off the bus near my home and heard the same odd sound yet again, clear as day. Again, no animal in sight. Within the hour my prayer was answered. I've never heard the sound again and I don't believe I'll ever discover what created it.
Even if it was a sign, you shouldn't have to wonder what the message is. A true sign is one that you immediately recognize and interpret through either stories you already know, common sense, or your intuition.