Why do they do that?

[KY_EnviroGuy]

6. Some sources say.....

when birds are disturbed during their sleep by unusual lights, vibration or sounds, they may erupt in song. Bright lights, loud noises, storms or high winds or earthquakes or a critter in their tree might do it.

When I search for "what birds sing at night?", Song Sparrows are not in any list I've found.

Peaceful event for you, regardless.......