O lol. Well that wouldn't really matter because they can be found anywhere. I don't think there's spots with better chances to finding the roaming legendaries than others. In emerald I'd just start at route 1 and go through every route in the game and I actually would find latios or latias. Another way that works well is use repels with your first Pokemon at lvl 49, so then the only wild Pokemon should be the legendaries unless you're in an area with lvl 50s and above. Someone correct me if I said anything wrong here, but I think what I said is right.

Edit: Didn't see that the birds were lvl 70; so just use a lvl 69 Pokemon first in order if you're going to use repels.