I think this is the right forum, if not, please move.

We have a pair of (I think) chickadees that have built a nest above the storen outside our living room window. The birds seem to have returned for the spring and are banging against the window.

We don't want to the birds to nest there - they pull out the insulation, leave droppings on the windowsill and attract cats (cat will try to climb up the window to get to the nest at the top).

Can we scare the birds, so they find someplace else to nest, or do we need to entirely block the opening? Other ideas?

Thanks.

I sympathise. It can be very messy. We used to get a lot of swifts in the UK but that was under the roof of an outbuilding so we just let them be and cleaned up once the chicks fledged. A neighbour of mine has the same problem above a balcony. She sits one of those pottery ornamental cats on the balcony at the beginning of Spring which seems to do the trick. I guess anything with a silhouette of a cat on the window sill might help as long as you change it's position from time to time. I've also heard a plastic snake has the same effect.

Just another thought. Why don't you simply remove the nest? If they try again keep removing the material. At this time of year birds might make a few attempts at nesting until they find somewhere undisturbed. Better now before they start laying.