You don't.
no you cant but you can get them through trade.
No, in Diamond and Pearl you can't catch the legendary birds.
there are unforunately non of them in pearl, youll have to migrate them from leafgreen or firered, or trade with a person who has caught them in platinum
mommy is soooooooooooooo cool lololololololol pen15
you have to take it from Pokemon fire red or leaf green...they are not actually in the storyline for Pokemon diamond and pearl
you get ruby and beat the game with fillin the pokedex.then you put the legendary birds into the PC and migrate them to pearl or diamond. it is fairly easy.
the legendary birds
Complete the national Pokedex release all your Pokémon in your PC, delete your data and you will have the birds and plus the legendary dogs but don't worry, you will still have all your Pokémon that you released back in your PC.
It's not a legendary in Pokémon Pearl.
the legendary Pokemon in diamond and pearl are dialga and palkia.
I believe you have to beat the elite four and obtain the national dex. i think then after that you can find the birds roaming around like wild beasts :D
There is no order for the legendary birds, so no.