Pigeons are a huge problem in Amsterdam. Wherever they find a gap, or a place to live, they will move in, build a nest and basically take over the place. That happened on our balcony as well.
On 22-03-2019 a company came to our house to evict a colony of pigeons that have been living on our balcony for about four years. The removal of the nests, the cleaning and installing of countermeasures went well, however, not all pigeons stayed away.