Kuro, originally referred to as Birds, are flying corvid Nitpickers that make their debut in the Donkey Kong Jr. arcade game. In most versions, they sport thick beaks and flap their wings in a brisk pace while flying.
Donkey Kong series
Donkey Kong Jr.
Kuro, referred to as Nitpickers or Birds, make their first appearance in stage 4 of Donkey Kong Jr. Like the Nitpickers in stage 2, these Birds similarly fly horizontally across the screen, descending progressively as they meet its margins. They flee off-screen after performing four such flights. Unlike those Nitpickers, they do not bombard Donkey Kong Jr. with eggs, and are designed to look more like ravens in most versions, given their dark coloration and chubby structure. They can be defeated the same way nonetheless, as falling fruit can put an end to them.
In the Atari 2600 port, a single bird flies left to right at the bottom of the stage. In the Intellivision port, they fly off the left or right side of the screen rather than doing their zigzag routine.
Donkey Kong Jr. Math
A lone Kuro, known as a nitpicker, appears in the +-×÷ Exercise mode of Donkey Kong Jr. Math. It hovers over the chains, showing which position Donkey Kong Jr. should fill. It will also show where Junior made his mistakes.
Donkey Kong (Game Boy)
A single Kuro nest can be seen in the Game Boy Donkey Kong, in Stage 9-4 of the Tower, a boss stage that resembles stage 4 from Donkey Kong Jr. It spawns two Kuro birds on-screen at a time. After rising slowly from their nest, Kuro fly horizontally across the room, moving down a short distance and turning back upon meeting the room's limits. They perform three complete flights, and flee outside the map of the stage afterwards. Kuro can not be practically defeated, as the stage they appear in presents no means of combat against them. They now attempt to drop eggs on Mario if they fly above him. Unless they are avoided, or deflected with a handstand, these eggs can plummet down on the character and cause him to lose a life.
In WarioWare Gold, two Birds have to be avoided by Donkey Kong Jr. as he climbs two ropes in the third difficulty of the Donkey Kong Jr. microgame. They fly on a straight line from left to right, across the ropes.
Names in other languages