We had a juvenile hanging about the garden for most of the last week in July/first in August. I think the adults migrate earlier and the juveniles make their own way a few weeks later.
This young bird was the most pathetic bird I have ever seen. It spent its days sitting on a fence post making a feeble squeaking noise and keeping its mouth open demanding to be fed. Every so often it would fly to the other side of the garden as if to try and make its 'parents' life a bit more difficult.
The 'parent' birds were meadow pipits who, being tiny beside a cuckoo, had to perch on the cuckoos shoulder in order to get food into its mouth. Quite a comical sight.