Natural selection. Those stupid birds just do not learn that perhaps our chimney is not the very best spot to build their nest. Already last year we had to rescue a fledgling sitting inside our Jotul oven. This year again a fledgling fell in the chimney but did not make it in the oven. After sitting at the bottom of the chimney for a night and calling for help, our landlord was kind enough to find the chimney opening and rescue it. The parents came to take care immediately after it was released in the garden.