Something else brand new for me. I have never seen a grey crow before. I see that Mama Swan has her eye on them...with her babies so close, I'm surprised that she lets the crows stay there. Here crows predate on the young of other birds and small mammals, and the swans are fierce parents. I can see, however, that if the swans move, the crows could get a straight shot at the babies. I have seen crows work collaboratively here, with one crow luring a mother rabbit away from her kits, while others stole the babies. A definite drama unfolding in your picture!