Black-legged kittiwake (Rissa tridactyla) Fledglings on nest, UK Black-legged kittiwake (Rissa tridactyla) Fledglings on nest, happy housemates. Almost completing the fledgling stage. They have made it through the challenging chick stage of the possibility of being predated from the nest. Now the next phase of life is dawning on them. The feathers have mostly transformed from the downy chick feathers into flight feathers.