In Heart Gold, what are those little symbols on the routes?

Question

The little symbols appear to be grey or red/gold and seem to be shaped like an eagle or bird of some kind.

Answer 1

I'm pretty sure Entei and Raikou are what you are talking about

Comments

Yeah I follwed those symbols and that's how I found Entei, Raikou, and Latias on HeartGold as well as Mesprit and Cressilia on Pearl and Platinum.