The flat next door to us has a pigeons' nest with two eggs. The two pigeons take it in turns to sit on the nest.
The owner wants to decorate the flat, including the balcony, in order to let it. How long does it take for the eggs to hatch and how long before the pigeons leave the nest?
Just be warned - they will come back and back again and try to nest in the same place. I think they must have more than one hatching a year, and they always invite their rrelatives to come over and make a disgusting mess. The owner would be well advised to take measures to make sure they don't do this. I have netting and pigeon off spikes to prevent them landing, but they are so persistent they keep trying to find even the smallest cranny.
We live in a lovely square in Prague, with a nice park in the middle. There are lots of pigeons but they don't make a mess and are welcomed by the locals, but I take the point about them returning to nest in the same place and will warn the owner of the flat.