We live in the country and our 16 months old female will chase bird shadows for hours, she doesn't get that the bird is flying overhead, she just sees the shadow on the ground and chases that until it disappears, usually of course the bird flies into a tree. She will do this all day if we let her and then she is exhausted. Any opinions on this?

Our Rotty used to growl constantly at her own reflection in the windows at night...looking back it is kind of funny, but at the time, she drove us nuts! (smile) We ended up closing the blinds and shutting off any lights at night that would cause her reflection to show up. And of course, we loved her for her silly ways! I guess that you don't have to worry much about your dog not getting enough exercise, the bird shadows do it for you. Let her have her fun...it could be worse...(smile)

Your girl is just bored and finding something to entertain herself with.

My female ACD does the same thing, I have about 4 feeders in a grove of trees outside my kitchen window and she will chase the shadows on the ground as long as the birds are in the trees.

But the moment I come outside she will run and get her ball, ready for me to play with her, let her play by herself or go out and do something with her to divert her attention off of the shadows.

She's definitely not bored, she gets walked regularly, goes with us in the car, people visit lots. Plenty going on for her.
Today just she lay in the grass and chilled out.