Bats
It's dusk, the heat of the day has brought out the midges which are hovering under the trees in hundreds, if not thousands. Drawn to the house by the lighted room. The doors and windows need to be closed over to stop them coming in.
Then , there they were, one or two at first, flying, fluttering like a small bird, between the house and the trees. Moving quickly, silently, but disturbing the evening air and trees with their movement, never still long enough to examine them closely, or take a photograph. Enjoying their evening feast.
Where do they live during the day? Who knows what neighbours we have in our trees. Hidden by the leaves during daylight. Coming to life in the warm evening air as the sun sets and the world starts to fall silent.