Pied avocets at approximately 6 weeks old. In the last photo, the avocet to the far right is a fully grown adult - you can se there is little different in size, but obvious differences in colouring on the back. The sub-adult still has grey in its plumage.
Follows on from this spotting http://www.projectnoah.org/spottings/127... by two weeks. Also last in this series.