It is not known to evolve into or from any other Pokémon.
Delibird is a red, penguin-like Pokémon with a white, hollow tail. Its face and chest are covered in white feathers with two, three-pointed crests above its eyes. Black markings surround its circular eyes, and it has a light yellow beak and feet. There is a single white spot on its stomach. Its feet have two digits each.
Delibird is omnivorous. It carries food bundled up in its tail. It normally gives stored food to its chicks, but has been known to share its food with humans stranded on icy mountains. Delibird's signature move, Present, allows it to carry special items in its tail that may cause damage or heal its opponent. In a flock, the Delibird with the largest tail is its leader. Delibird tends to live in mountainous regions, making its nests over sharp cliffs; one notable area of the world is around Mt. Everest.
Delibird debuted in Delibird's Dilemma, under the ownership of Santa Claus. Ash's Totodile shot a Delibird that was delivering presents clear out of the sky with a Water Gun-propelled snowball. As a result, Pikachu and his friends had to help the Delivery Pokémon find the five presents before midnight.
Delibird, the Delivery Pokémon. Delibird's most unique attack is giving presents. However, some of these presents have been known to explode. Sometimes, Delibird's presents can actually restore energy to its opponents.
This concludes the entries from the original series.
Delibird debuted in You Ain't Nothin' but a Houndour under the ownership of the Masked Man, where it, along with his other Pokémon, attacked Gold. It is one of his most commonly used Pokémon. It appears to be the same Pokémon used by him in his alias, and was strong enough that it allowed him to capture Ho-Oh. However, Gold was able to knock it out with Polibo's Perish Song attack.
Pokémon Stadium 2: Delibird stars in its own mini-game called "Delibird's Delivery." In this game, players collect presents from one side of the field to the other. The player must avoid Swinub that scurry around or they will trip the Delibird and cause the player to lose the present they were carrying.
Delibird has Insomnia as its Hidden Ability although it already has access to Vital Spirit, another Ability with exactly the same in-battle effect.
Aspects of Delibird's appearance appear to come from the rockhopper penguin. However, its red and white color scheme, its ability to give presents, and the appearance of carrying its sack-like tail is likely to have been derived from Santa Claus and possibly the white stork. Delibird may have also been inspired by puffins, which are penguin-like birds that still have the ability to fly.
Delibird is a combination of delivery and bird. Deli may have derived from the Adélie penguin. Pronouncing Delibird with the same inflection as delivered yields a very similar sound, with the "b" and "v" being the only variation between the two words.