Bird Nest

Birds choose the oddest places to nest don`t they?
Going down the alley beside where I work earlier this week I head a lot to twittering and bird calls that sounded like a nest of young chicks, but I couldn`t see where it was coming from. Then the next day I spotted a starling dart quickly across in front of me and disappear, and I could again hear all the tweeting going on. As I looked up an adult bird sat by a metal grid in the wall. Looking closer at the place the next day I could see that the top corner of the grid was broken making an entrance hole and poking through the lower part of the grid were a few bits of twigs or straw, so I`m fairly certain now that we`ve got a nest of starling in the wall of where I work! Yet, it`s quite a busy alleyway with people always up and down.
I wonder how many other people who have walked up and down there have spotted it?