Skylights are often indented into the roof a building, and I have found that occasionally, birds such as pigeons may decide to nest on a skylight. This you may not immediately consider to be an inconvenience, but I assure you, the sight of bird droppings on your skylight is not a pleasant one, and not being able to open your skylight for fear of birds and their droppings is not a pleasant experience either. So, how can birds nesting on your skylight be prevented? The first thing I would like to note here is that this is a rather rare problem so I would not worry about it too much. If, however, you do notice birds nesting on your skylight, you may wish to attempt the techniques below. Firstly, remove the nest, then proceed with installing the countermeasures. The first one most people would suggest is a net, stopping birds from walking on that area, and making it uncomfortable for them. This usually fails as the birds simply place twigs on the net until they can walk on it. In the case of skylights, the net may work, as it prevents there from being an indentation in the roof, so reducing the popularity of the site for birds. In the one time birds have nested on a skylight of mine, I used the net and it worked perfectly well. If the net fails, perhaps spikes would work. If not, you may be in need of a specialist.