House Martins.

Hello, 

looking for some info from anyone. 

We are lucky enough to have house martins return every year, however this year we have got a pair building a nest on top of an open bedroom window. 

I am just interested to know if this has been heard of before by anyone? 

It looks to be made of grass but difficult to see the whole nest as we are now unable to open the window fully or close it. We can just see the little birds through a crack at the top and they stare at us and chatter away. 

Its enchanting. 

Sally