If they are flying over, nothing. You can perhaps try positioning a fake owl or other predatory bird on your roof, but this is limited as most birds get used to them and ignore them after awhile.
If they are landing on your deck, you can try running pie plates of other reflective materials around suspended. Birds are shy about movement and may stay away.
Otherwise, seal it, and wash it.
If the birds are flying into your area (not walking up, such as ducks coming in from a nearby pond) try stringing clear mono-filament fishing line above your head, say off the roofs edge. Make sure the lines are high enough so people will not run into them, and make sure you string enough lines to be effective. The birds will be scared away 'freaked out' by the lines, afraid they will get tangled in them, and will leave your balcony alone.
If they are sitting on a railing, for example, there are items sold to boaters to discourage birds from landing on the top of things. Some are made of sharp spikes, but others are just bristly like a big nylon hair brush.
One way to have birds to stop pooping there is to make sure to remove all bird feeders in your area. You also don't want to put a lot of trees in the area of your verandah.
by pooping
This fear is called Ornithophobia. the fear of birds.
You can create a cozy outdoor seating area with chairs and a table, tend to a small garden with potted plants, enjoy a cup of coffee or tea, read a book, or simply soak up some fresh air and sunshine.
kill them
There is a product out there called Bird-Deter that is specifically designed for use on a mailbox. It is a very simple design but it keeps birds off of a mailbox with harming them in any way.
yeah kill it
Because u have to get it out of your system
Drop it off a balcony
To deter birds from building nests on a balcony, try installing physical deterrents like bird spikes or netting. You can also hang shiny objects or use scare tactics like predator decoys or ultrasonic devices. Ensure that the balcony is kept clean of food and nesting materials to discourage birds from staying.
tell your poo to toughen up?
No they don't. They love pooping on cars.