They apparently have to go to great lengths to preserve their crop from the birds. Nets are used and they also have a contraption that consists of a long pole with a cross piece attached to the top of it. Black scraps of cloth which could resemble a bird dangle from the both ends. At intervals a bird call is emitted and the cross piece is spun around so that the scraps look like birds in flight. The bird call may be that of some raptor. Hans said they used to use some sort of boom like a gun but the locals complained.