Pokémon Mystery Dungeon: Blue Rescue Team Tips

An Easier Way To Recruit Legendary Birds
You can try this for Articuno Zapdos and Moltres, it probably won't work every time, but it has worked for me. Okay so you go and fight them the second time (they won't join the first time) and after you start battling, go along the wall of the room, letting the bird follow you. After you circle the room once, defeat the bird. It will very likely join you.
1. Make sure you have only one Pokemon, send the rest back. (Two may work)
2. You should have a strong Pokemon that can handle the birds' attacks.
3. I think this also works on Groudon, but you have to circle the room 3 or 5 times.