The chocobo was created and designed by Koichi Ishii, a video game director who worked on various Final Fantasy titles. The chocobo appears remarkably similar to and was likely inspired by the prehistoric bird Gastornis. Hiromichi Tanaka has speculated that the chocobo concept may have come from Kyorochan, a character in television advertisements for Morinaga & Company's chocolate candy, which is also a bird with the call of "kweh". Morinaga has also released a tie-in product, Chocobo no Chocoball (チョコボのチョコボール, lit. "Chocobo's Chocoball"). Another likely inspiration was Hayao Miyazaki's Horseclaws, which appear in the manga Nausicaä of the Valley of the Wind and the anime film of the same name, which Final Fantasy creator Hironobu Sakaguchi once cited as an influence on his series. In turn, Miyazaki's Horseclaws were inspired by the extinct Gastornis species. This mythical creature is a “cousin” of the ostrich and is designed to have yellow feathers, but there are rare Chocobo breeds that are capable of giving birth to different-colored chicks.