[Daily Photo] Swans in the pond

I found a small pond in south Ann Arbor. The frozen water surface was starting to melt at this time (the end of winter), and these three swans were swimming in the open water of the half-frozen pond. I took many pictures of them and chose this one because they were all with the same posture. I remembered one time I was at Gallup Park shooting swans. An older man told me that the swan with gray feather and beak was the young one (like the swan on the left side of this photo). When it matures,  the beak becomes orange and the feathers become snow white (like the other two swans in this photo). I found out that this species of swans are called Mute Swans.