I had a bird back in 2008 coughing, sounded just like a smokers hack. I ended up losing the bird to whatever was causing the cough... but to this day i have never heard a pigeon make a noise anything like it.i have a few pigeons that are coughing or seems like they are. not very active anymore and just wants to sit and not be bothered. seems like somethings in there throat?? what could this be?? any ideas??