[Perhaps surprisingly, McGillis reacts well to instruction—so much so that it's a little like guiding a big cat back into its cage, sedated and stumbling. There's a lot of power in that enormous frame, enough to snap someone's neck or worse things still, yet there's zero threat here. He might not take well to demands, under ordinary circumstances, but this feels different. Being taught, as opposed to being ordered. So he can justify it as necessary, not patronizing, and make his own excuses to himself later on.

What made him happy...? Not much. Not much appropriate for this kind of setting, anyway. It takes him some time to think, working through it aloud.]

...birds. I couldn't find any, when I first arrived, which was unusual. Surely birds exist in any kind of world.

[Did they all die? Were they exterminated? Did they migrate? McGillis frowns, lost in his own train of thought.]

Turdus merula, Cyanocitta cristata, Zenaida macroura... all absent. No other animals, either, or plants that I could tell. Everything is dead or dying.

[Such a sad state of affairs. And he's not exactly happy, pretty far from relaxed, but keeping his brain active means he's distracted from other things, like tensing up or crushing his companion. His fingers are pliant, and touch softly to Prompto's arm, where they naturally fell. This was a dangerous man, but... it's harder to see that, talking about robins and doves.]