A useful tip to identify what is hatching or has indeed been hatching is to look in the foam which is usually caught up by the bank at the edge of the river.

Flies get trapped in the foam and are easily seen and identified, it’s particularly useful when the insects are small and difficult to see on the water or identify in flight.  Clearly it’s not just aquatic insects that get trapped terrestrial insects do too.

The picture below shows Large Dark Olives trapped in the foam on the River Wharfe on Thursday this week. 

Flies In The Foam

Flies In The Foam