the bird was in season 1, Exodus part 2 really close to the end of the show. I'll cut and paste from spooky's transcript which you can find at www.lost-tv.com

We see Jack, Kate, Locke and Hurley walking through the jungle.]

HURLEY: So, dude? What do you think is inside of that hatch thing?

LOCKE: What do you think is inside it?

HURLEY: Stacks of TV dinners from the 50's, or something. And TVs, and cable, some cell phones, clean socks, soap, Twinkies -- you know, for dessert, after the TV dinners. Twinkies keep for, like, 8000 years, man.

LOCKE [laughing]: I like Twinkies, too.

HURLEY: C'mon, really, what do you think is inside?

LOCKE: Hope. I think hope is inside.

[They continue walking. A large bird calls and flies away, scaring everyone.]

HURLEY: Whoever named this place Dark Territory? Genius.