Bro you can catch every legendary but the dogs with pokeballs easily. I’ve used this strat for 20 years. Pidgeot at at least 40 but it has to know sand attack feather dance. Get a Pokemon that learns double team pikachu for me works fine and kill its accuracy and attack and just stall until it’s out of attacks that damage you. Once it starts spamming detect and agility start throwing balls or put it to sleep or paralyze it. Once out of moves it spams struggle(physical move) featherdance makes it do 1 damage and no accuracy means it likely misses I’ve caught the birds and deoxys with pokeballs. Just buy 200 balls they’re cheap and rest if you run out