Last one in...

...is a rotten egg!
Obviously neither of these Canada Goslings is an egg anymore, rotten or otherwise.
I spent quite some time watching them skitter around, never departing more than a few inches from each other. Both Mama and Papa were close by, but the goslings preferred each other. They ran after a grown Mallard, they pecked in the grass, they flopped in the shallows of the pond and buried their faces in the water looking for food. It was quite a show!
Most of all, I enjoyed their exuberance in all things new.