Nest building

Yesterday I was out in the garage, working on my pickup truck.  I kept noticing a couple of birds flying in the garage, but didn’t pay a lot of attention to them.  After a while I realized that they were building a nest in the corner of the garage!  Now I’m faced with the dilemma about what to do.  Should I destroy the nest, or leave it alone?  If I allow the birds to nest there and raise their family, I’ll need to leave the garage door open all of the time.  I’m not real keen on that idea, since I have a lot of expensive tools in there.  And I’m not real keen on the idea of bird droppings in my garage, on my motorcycle, truck, or tools.  But I’m a softie at heart, and can’t quite seem to be able to bring myself to destroy the nest!  I wonder how long it will take from the nest building stage to the completion of the baby birds being raised!  I don’t even know what kind of birds they are.  Maybe I’ll pull out the bird book and see if I can Identify them.