I have an ugly dying fern hanging on my porch because of this ~
However, I would never destroy one that got past me and built a nest. I love watching the progression. I never touch it of course and get on a step stool to look at the nest. I leave it hanging so the neighbor's cat won't get it!
By the way, if you want an easy way, foolproof way to keep birds out of your plants, especially ferns ~ here's my handy-dandy sure fire way. Put hair in the fern. Except for this year obviously, I go to my hairdressers and get a little sack of hair, then put it down in the ferns. Works every time!!!
I will post a pic of the babies once they are born!