So as the bird watched the three mice he see them all separate they all go into a can that was made into a house type area.
The first mouse has straw over his to make in kind camouflage to stay hidden from animals and predators. but it is not the most stable house. So as the bird sees the first mouse come out then go back in he knows he is still in there and it is getting to dinner time. So the bid swoopd down to try to grab the mouse but the mouse saw the bird flying around earlier so he was ready for the bird to come down and try to get him so the mouse