Bird dog

My grandson's dog, Cyber, behaves just like a bird does when it is covered. When I entered my daughter's home Cyber jumped all over me as I was taking off my winter clothes. He couldn't wait to see me. My daughter made him sit but even as he was sitting he managed to scoot towards me. I asked her to hold the dog until I had my coat off. Then, when I asked her to release Cyber I tossed the coat over him. I expected a playful reaction but he just settled down on the floor and remained quiet just as a bird does when covered. It wasn't until my daughter lifted the coat that he became active again.