Hanging baskets full of ferns are a natural place for birds to nest. The hanging basket is off the ground and difficult for predators to get into, and the ferns provide cover so that the birds feel safe and secure. Birds in your fern basket can kill off the ferns over time and they can also create a mess below the basket with feces, food remnants, debris from the nest and shed feathers. Preventing the birds from nesting in the first place is far easier than removing the birds once they have appeared.
Stick a children's pinwheel in the hanging basket beside the ferns. The motion of the pinwheel startles the birds away. Choose a pinwheel with shiny arms so that the flashing light further disturbs the bird.
Cut long strips of shiny Mylar material and tape them to the bottom of the basket. The shiny strips flutter in the wind, preventing the birds from settling.
Drape the top of the basket with bird mesh, hanging it from the same hook that you hang the fern basket. Bird mesh is a fine mesh that allows for normal watering and sun exposure, but which keeps birds from being able to enter the basket.
Slide bamboo skewers into the soil in the fern's hanging basket, allowing the sharp ends to stick up. This prevents the birds from wanting to land.