One Swallow doesn't make a Summer: how about ten?

A walk around the Fen with old friend Red O'Hara was fairly unproductive by recent standards: Bittern, Bearded Tit and Kingfisher as usual, but too fleeting to photograph. The Riverside and Lackford Run are impassable, so not much scope for walking. Amazing thing, though: up to ten Swallows were hawking in front of Fen Hide: a late date for so many, I would imagine....