Louie's notes
Like Captain Olimar, Louie takes notes too, but his notes are about how to cook enemies. While Captain Olimar's notes would be useful to a scientist or biologist, Louie's would be useful to a chef. Interestingly, Louie references ingredients found on Earth (cultivated in oxygen). These ingredients could not possibly be known by Louie, as Hocotate has a severely different climate. This is most likely because Hocotatian plants often have a similar appearance to those found on Earth so Louie uses the names he is familiar with for a completely different plant. Some of his notes say that the creature is inedible, like the clover. In these cases, he states a humorous side effect of eating one.
Louie's Notes, like the Sales Pitches for treasures, are not shown in the beginning of the game and are unlocked by defeating the Titan Dweevil.
Example
"Eaten raw, this predator's luxurious legs are bold and full flavored. What a satisfying crunch!"
Musings of a Sidekick
On June 18, 2009, Nintendo of Europe released an article titled "Louie's Notes: Musings of a Sidekick" at its website. It is essentially a humorous commentary written from the point of view of Louie, comparing himself and Olimar to other famous Nintendo duos (Mario and Luigi, DK and Diddy Kong, Link and Navi, Pikachu and Pokémon Trainer), as an attempt to promote the New Play Control! edition of Pikmin 2.