It's a Takkuri.
This odd looking bird with two fluffy ball looking things on the sides of its enormous head will steal Rupees, Bottles, or even the Sword if it touches Link. Whatever it steals will appear in the Curiosity Shop, so it's safe to assume its a lackey of either Sakon the Thief or the Man from the Curiosity Shop.
There's only one of these in the entire game, and it is located in Termina Field at the entrance to Milk Road. This is probably the enemy with the most health in the game because it takes a very long time to kill. It can be killed up close, but Fire Arrows are the safest and fastest way to kill it. When killed, these things drop a whopping 200 Rupees.
The Minish Cap
Takkuri are enemies found within The Minish Cap that are very similar to Crows. The primary difference between the two is that Takkuri have a red body color instead of blue. Unlike Crows, Takkuri will actually steal rupees from you when they attack and later on in the quest, a Takkuri can even steal the Graveyard Key from Link while in the Royal Valley.
|Crow & Takkuri|
|Appears in various areas. The black one is Crow. If you touch Takkuri, he will steal Rupees from you, so be careful!|
Takkuri Sprite from The Minish Cap
- "Takkuri is a breed of slow-flying vultures famous for their ability to pick the pockets of careless travelers." — (The Great Hyrule Encyclopedia).