Huey, Dewey, and Louie are triplet cartoon characters created by storyboard artist (screenwriter) Carl Barks for The Walt Disney Company from an idea proposed by cartoonist Al Taliaferro. They are the nephews of Donald Duck and the grand-nephews of Scrooge McDuck. Like their maternal uncles, the brothers are anthropomorphic white ducks with yellow-orange bills and feet. The boys are sometimes distinguished by the color of their shirts and baseball caps (with Huey wearing red, Dewey wearing blue, and Louie wearing green). They appeared in many Donald Duck animated shorts, as well as in the television show DuckTales and its reboot, but the comics remain their primary medium. While the boys were originally created as troublemakers to provoke Donald's famous easily-triggered temper, in later appearances, beginning especially in the comic books stories by Carl Barks, they are shown growing to be heroes in their own right and valuable assets to him and Uncle Scrooge on their adventures. All three of the triplets are members of a fictional scouting organization called the Junior Woodchucks.(via Wikipedia)
Huey, Dewey, and Louie are the sons of Donald's sister Della Duck; in Donald's Nephews, their mother is instead named Dumbella. In the original theatrical shorts, they were originally sent to visit Donald for only one day; in the comics, the three were sent to stay with Donald on a temporary basis, until their father came back from the hospital (the boys ended up sending him there after a practical joke of putting firecrackers under his chair). In both the comics and animated shorts, the boys' parents were never heard from or mentioned again after these instances, with the boys ending up permanently living with Donald. All four of them live in the fictional city of Duckburg, in the fictional state of Calisota. In the theatrical shorts, Huey, Dewey, and Louie often behave in a rambunctious and mischievous manner, and they sometimes commit retaliation or revenge on Donald. In the early Barks comics, the ducklings were still wild and unruly, but their character improved considerably due to their membership in the Junior Woodchucks and the good influence of Grandma Duck. As the boys mature, they prefer to assist Donald and Scrooge in the adventure at hand.(via Wikipedia)