These seven pictures show a fledgling Eurasian Blackbird passing an item to an adult male, which immediately flies a few yards away and transfers the item to a fledgling, probably the same one; I can't say for sure as I didn't see the fledgling fly away from the gravestone where it was perched in the first four pictures.

I photographed this 17 second sequence in St. John's churchyard, Hampstead, July 5, 2013 just after 8 a.m.

The item being exchanged may be a large food item, such as a mashed-up worm, or it may be a pellet. Eurasian Blackbirds are known to form and regurgitate pellets containing indigestible fragments of food items, see http://www.britishbirds.co.uk/search?model=pdf&id=2203 and
http://davehubbleecology.blogspot.com/2011/04/bird-pellets-theyre-not-all-about-owls.html . The last picture gives the best view of the item.