Nitpicker

Nitpickers, also known as Birds or Stookybirds , are flying avian enemies that make their debut in the Donkey Kong Jr. arcade game. Ever since their original appearance, Nitpickers remained largely unchanged in behavior.

Donkey Kong Jr.
In Donkey Kong Jr., a flock of Nitpickers is released by Mario to impede Donkey Kong Jr. from progressing in stage 2. The birds are depicted yellow, having a distinct magenta coloration on their wings and beaks; likewise, they are slender and bear an unflinching attitude. They proceed in flying in a straight line after being sent by Mario, traveling along a wide platform. They then descend into the a small opening in the platform, continuing their flight thereafter in the opposite direction, under the platform. Occasionally, Nitpickers drop eggs when turning the other direction. The eggs, as well as the birds themselves, are harmful for Donkey Kong Jr. and can drain one of his lives upon coming into contact. On the other hand, Nitpickers can be defeated by having fruit dropped on them.

Along with Snapjaws, Mario employs another flock of Nitpickers in stage 4. These Nitpickers similarly fly horizontally across the screen, descending progressively as they meet its margins. They flee off-screen after performing four such flights. Unlike the other type, they do not bombard Donkey Kong Jr. with eggs, and are designed to look more like ravens, given their dark coloration and chubby structure. They can be defeated the same way nonetheless, as falling fruit can put an end to them.

Nitpickers return in the Game & Watch Donkey Kong Jr., where they only follow a straight path from left to right and pass by a set of vines located at the bottom of the screen. They spawn at the left side of the screen, do not drop eggs and do not steer back like they did in the original game, merely disappearing after encountering the right side of the screen.

Donkey Kong (Game Boy)
In Donkey Kong for the Game Boy, Nitpickers are succeeded by three species of birds that retain and mix their behaviors. In order of appearance, these consist of Kaibādo, Hōkusu, and Kuro. They spawn from nests that are mostly placed high above the ground, subsequently performing three flights across the room. The end of one flight is marked by their encounter with one of the room's margins, after which they descend a little and change direction. They occasionally drop lethal eggs on Mario, provided the protagonist walks underneath it.

Captain N: The Game Master
Nitpickers are featured as minor impediments in the episode "The Lost City of Kongoland" of Captain N: The Game Master, where they resemble vultures. They are depicted with long tubular beaks, tapering heads, and bulging eyes, as well as straight and focused looks. In the show, Nitpickers are summoned after Simon Belmont blows into a flute while he and the rest of the N Team are cruising down a river in Kongoland. Their beaks are said to be poisonous, and Kevin warns his crew to take cover. The birds immediately show and try to raid the team's vessel, but as they swoop down, Princess Lana draws a bazooka and counter-attacks them with large cork projectiles.

Mario vs. Donkey Kong series
Mario vs. Donkey Kong features modernized Nitpickers. In Donkey Kong Jungle, they appear as yellow birds with an orange beak, and routinely perform their traditional flight pattern from their nests; in Fire Mountain, they are replaced by Firebirds. These lay eggs covered in flames, which cannot be protected by a handstand.

They appear again in Mario vs. Donkey Kong 2: March of the Minis, more clearly depicted with metallic-looking joints under their wings. They appear in the Jungle Hijinks battle with Donkey Kong. Their main purpose is to serve as an obstacle to the Mini Marios and swoop down on them if they're underneath it. Every time Mini Marios hit Donkey Kong, the Nitpicker will start dropping eggs on them. Mini Marios can drop a Banana on the Nitpicker to temporarily destroy it.

Nitpickers reappear in Mario vs. Donkey Kong: Minis March Again! for the Jungle Rumble boss battle.

Trivia

 * The name "Nitpicker" is shared with the red bird enemy from the game , also by Nintendo.