I had reason to walk to Broad Street and back a little while ago. My 0.6 mile trek had quite the soundtrack. Mockingbirds, robins, English sparrows, song sparrows, starlings, red-winged blackbirds, crows, and mourning doves... and those were just the birdcalls I can identify. I've seen other kinds of bird in that half-mile-plus span -- cardinals, grackles, bluejays, and slate-colored juncos, to name a few -- who didn't make their presence obvious this afternoon.
The varied nature of the sounds, and the complete independence of the different voices all calling at once, reminded me of the sound of an orchestra warming up while they await the conductor's cue to tune up with a Concert A pitch.