Nitpicker

Nitpickers are flying avian enemies that make their debut in the original arcade game, Donkey Kong Jr.. Ever since their original appearance, Nitpickers remained largely unchanged in behavior and continued to star as malicious creatures in various games that succeed and closely follow the gameplay of the arcade classic.

Donkey Kong Jr.
In Donkey Kong Jr., a flock of Nitpickers is held captive by Mario, who commands them to undermine and 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 getting struck by Mario's whip, and travel along a wide platform. They descend into the platfrom's small opening after traveling further to the right, continuing their flight thereafter in the opposite direction. Occasionally, Nitpickers drop eggs when turning left. 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.

Also in Donkey Kong Jr. exists a species of bird enemies which display a similar demeanor to that of Nitpickers. Along with Snapjaws, they are used by Mario in stage 4. The aerodynamic foes in question fly horizontally across the screen, descending progressively as they meet its margins. They flee off-screen after performing four such flights. Unlike the earlier-introduced Nitpickers, 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 as Nitpickers nonetheless, as falling fruit can put an end to them.

Nitpickers return in the Game & Watch edition of Donkey Kong Jr., where they only follow a straight trajectory and pass by the bottom set of vines.

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 prevail and try to raid the team's vessel, but as they swoop down, Princess Lana draws a bazooka off-camera and counter-attacks them with large cork projectiles.

Donkey Kong
Two forms of Nitpickers make a reappearance in Donkey Kong for the Game Boy. They first appear in Stage 2-9 in the Forest. They fly out of their nest and cross the screen horizontally. When they fly over Mario, they stop and try to drop an egg on him. Touching the eggs or the Nitpicker itself kills Mario. The second variety of Nitpickers only appear in Stage 9-4 in the Tower. They have a different appearance, but the same patterns as the first variety.

Mario vs. Donkey Kong series
The Mario vs. Donkey Kong series features Nitpickers in a more modern appearance, with yellow feathers and an orange beak. Fiery Nitpickers are introduced in Fire Mountain.

They appear again in Mario vs. Donkey Kong 2: March of the Minis where they behave in the same way as in the last game, however this time around they appear to be more mechanical than in previous appearances.

Nitpickers reappear again in Mario vs. Donkey Kong: Minis March Again! but only in two boss battles.