Flap

We had to be in Stratford early this morning, and I went down to the river to see what birdlife was about. The swan flock is a bit depleted now due to the avian flu epidemic.  I got talking to someone about the swans and the flu etc so I was temporarily distracted.  All of a sudden there was a massive flapping and whooshing as the swans flew off downstream, attracted by what I'm not sure, someone throwing food I suspect. 
I missed most of the action but caught the last few. I hope there was some food left for them. 
Snooze , you lose as they say.