agreed.
Them being there would essentially make them scarecrows, and make the birds hesitant to move in. but anyone who has ever fed chickens or other outdoor farm fowl will know that as soon as you throw feed and step away other hangers on, (i.e. doves, crows, and sparrows) will dart in as soon ass they see you scatter food and step away.
this was pretty much an agrarian society, it's all they had left, so the birds would be conditioned this way.