Songwriters can compose words and/or music. If you want to compose better lyrics you might study English; if you want to compose better melodies you might study music. If you want to write devastating protest songs, you might want to study politics. Education takes us to many different places.
write a song...
To become a teacher, you will have to major in education. You can always minor in history. That should help you get a history teaching position.
No training is required, but your local songwriter's association can be helpful to your learning process.
singer,guitarist and songwriter
ethology is a major itself, but not many colleges have a major in it i can think of 15.
singer, songwriter and composer
well just go to google
Country songwriter/singer
To find a songwriter, visit your local open mic or songwriters association. There are no prerequisites to become a songwriter. Anyone can write a song. Whether they get paid for it is another matter. To learn more about the career, join your local songwriters association or visit http://www.nashvillesongwriters.com
Geology or geophysics
Nursing
The best answer would probably be a major in Psychology.