It's a time of year when Bluebottles and House-flies find their way inside as soon as you open the back door.
One fly on the kitchen window is rather different. It's smaller and much thinner than a house-fly. Seen against the light it appears reddish. What distinguishes it form the average fly is its unusual behaviour. Most of the time that it is sitting, or walking slowly on the glass, it moves around its two front legs either together or one at a time, in a mime that reminds me of someone searching for their car keys on a desk in the dark.