The young chicks, now at 18 days continue to thrive.  They are more mobile on the nest ledge and I watched one flapping and moving around the scrape this evening.  In spite of a 2 1/2  hour session not a great deal took place for long periods, quietness mostly being the order of the day. But patience always pays dividends.  Suddenly  the tercel arrived with a small plucked bird  which was  possibly yet another woodpecker, it had remains of white feathers on the wings and I can't think of any other bird that fits the description.   The hand over, which  I nearly photographed,  took place in the oak tree and then down she came to the nest to feed the chicks, all pretty routine stuff.  The feeding took just a fraction of the usual time,  a minute or two.   On completion, she left the ledge and came to a perch very close, but out of sight of the hide and screamed loudly, flying back to the oak tree  she continued to scream which I took as a sign to the tercel to get  more prey.  In her usual position she seemed to wait for his arrival.