The following birds prefer the listed beans.

Anghel: Bitter Black Beans.
Kazuaki: Country Millet.
Nageki: Country Millet.
Okosan: Swollen Hemp.
Ryouta: Calm Corn.
Sakuya: Racing Blend.
Shuu: None, although Racing Blend will trigger various reactions.
Yuuya: Bitter Black Beans.