How was Sasuke able to summon 2 different types of creatures? Summoning is a technique which is used to summon creatures. Most of the time, many of them were able to summon only 1 type of creature only (like, for Naruto, it's frogs).

But Sasuke is able to summon snakes and hawks. So my question is, how he is able to summon 2 different types of creatures?
Well officially, only Pain and Sasuke are able to summon more than one creature. Pain's ability seems more realistic since each summoned animal had the black rods (he may have gotten control of their dead bodies and utilized them during battles with his vast chakra).

Sasuke is a different issue. There's no evidence that he ever signed off a contract with the hawks. Seems like Kishimoto pulled it off just to blend with the 'Taka' group name.