Birds can be a problem... the Van Brunt brothers made the first fluted feed cup to make an effective grain drill. Their farm was located near Wisconsin's Horicon Marsh, a large bird sanctuary and resting place for migrating birds.
They were sick of the thousands of birds eating the wheat seed they spread before they could get it harrowed in.
It was a sucess- and that's why they built a factory in Horicon. It's now owned by Deere and home of their lawn mower line and not drills any more.
Just a bit of useless ag trivia...