I assume the leaves are a clue?

I assume the leaves are a clue?

Observation - I assume the leaves are a clue? - UK and Ireland. Description: A montage of two individuals, which I am assuming are the same species. They were resting on the bridge timbers above the Great Raveley Drain, both flew off after a few minutes.

A montage of two individuals, which I am assuming are the same species. They were resting on the bridge timbers above the Great Raveley Drain, both flew off after a few minutes.