I've always assumed that a shearer was someone shearing a sheep. Then I learned "Band O' Shearers" and wondered why they were shearing the poor sheep in autumn rather than in the spring (I expect that a sheep would prefer to keep its wool in the winter and lose it in the summer). I just listened to a recording of the song and noticed that the singer says (in the last verse) "and when the HARVEST, it be done..." So now I'm thinking maybe "Band O' Shearers" is about harvesting grain (which would make sense in the autumn) rather than shearing sheep? Can someone explain these details to a confused city girl?