Biten off more than they can chew?

The beavers we had in the garden 2011 moved on upstream and then crossed over to a bigger stream. Seem to have grown considerably, if the size of their "damage" is anything to go by. This is one of 3 neighbouring trees that have been visited. One has been brought to the ground, the second is at least 50% cut. Either they abandoned this one or will return later.