Do they snore?

I was thinking about this the other night - what do (wild) birds do at night? Do they sleep? Where? In the trees? I don't see them. I certainly don't hear them, so they're not around doing their thing. Are they partying down at some bird nightclub somewhere? Are bird nightclubs crowded with guys pining for a mate known as foul-markets? Is there some society like the masons where they gather and sacrifice virgin worms to the eagle gods? OK, I'll stop now.............