This is not porn

[Redneck]

Someone has suggested that yuki's bird could be Yuki herself....Read "Dance Dance Dance" chapter 30 paragraph 265

"«Okay, suppose you were a bird,» I said, «and flying was something you really enjoyed and made you feel good. But there were certain circumstances that, except on rare occa*sions, kept you from flying. I don't know, let's say, lousy weather conditions, the direction of the wind, the season, things like that. But the more you couldn't fly, the more you wanted to fly and your energy built up inside you and made you irritable. You felt bottled up or something like that. You got annoyed, maybe even angry. You get me?» «I get you,» she said. «I always feel that way.» «Well, that's your sex drive.»"

Or it could be something to do with sex or being unaware of dangers...I don't know.