I left for the weekend and came home to two mocking birds making nests (I think) in two of my hanging ferns. Can I put fake snakes on top of the nests?
Fake snakes would work. You can also put old CD's on a string. The movement and light will scare them away.
Put crushed egg shells around your ferns, the birds will not make nest as the edges of the shells are too sharp for them to build on.
Lay chicken wire type material over the planters or tie holographic ribbons around it