Why does it get real quiet around twilight?

I live in a place in the San Fernando Valley (a suburb just north of LA) that is often noisy, but almost every time around twilight it gets real quiet. I googled this question and got nothing. So I came hear thinking you may be tuned-in enough to answer this fascinating (to me) question.

 

End of 'rush hour' - people heading home from work, by Twilight have already arrived, therefore less traffic. Kids out playing, have, by twilight been called in. At twilight, its too early for any 'night club' or bar activities too, so another reason for it being inordinately quiet.

 

Where I live, at twilight the songbirds roost for the night. The first hint of daybreak is one solitary bird singing in the darkness about 30 minutes before the sky starts to lighten. By dawn it's the most beautiful chorus.

 

I like it during the spring and summer at night,its usually quiet...

In august those stupid chirping birds or whatever they are start up at night and its bloody noisy!!