Waxwings in St Albans

While on a lunch time mission (13:30-14:00), I was lucky enough to come upon 11 Waxwings perched in tree tops along Mayne Avenue where it runs alongside Bedmond Lane in NW St Albans (map ref: TL128064). The Waxwings were not in a flock but rather one or two perched in each tree, none of which was berry bearing. Indeed there were no berry bushes in the immediate vicinity.(although various berry-bearing ornanmental shrubs were seen when I later drove further into the estate). All the Waxwings were apparently fly-catching, flying out from their perch before turning and gliding back to the same perch, or moving along to the next tree. It was mild at lunch time, about 11oC and calm, but I could not see, even with binoculars, what the Waxwings were catching (if anything). I have not seen too many Waxwings previously but all have been feeding at berry-laden bushes and usually in a flock.