Sparrows are monotonous once they get going. (All of the non-monotonous bits here are other birds, except possibly the wedge-shaped thing at 1:22, which might be the smoke alarm asking for a new battery.)

7:22, I mean

I'm really not sure about that thing. It *sounds* exactly like the smoke alarm, but as a waveform it looks like this. Which at first sight might be a beep plus echoes, except they're not equally spaced.