I'll take a shot at this, because this is my hypothesis:
Since flies have very good eyesight and a strong sense of smell, they might see their reflection in the mirror, and smell anothers fly's pheromones on the mirror. So it would only be natural for that fly to linger there to seek out a potential mate. LOL, that's my final answer!

• A house fly is very active we all know but when it comes near a glass or mirror it is not that much active wh?
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