So, there's this one fic I'm currently looking for (will attach link once I can find it - pretty sure there's at least two of them, will have to get back to you on that later) but my brain basically went "what if fic... but add Danny before the Bats and Birds realize they fucked up?"
"Y'know, I never hear you whistle." Red Robin froze, holding still on the rooftop.
There'd been no warning before the voice spoke up, no shift of gravel as footsteps approached, no displacement of air to signify a flier. Just... one moment, Tim was alone on the rooftop, listening as his family communicated in that secret language that he was excluded from. The next, someone was behind him.
It took him a moment to decide what to do, before shifting so he'd be half-facing the potential assailant.
"Which is weird, since all the others do." There was a man floating, cross-legged, over the roof. "What do they mean, by the way?"
Tim stared at the man, potentially an alien - there were no humans with eyes like that, without some serious mutations. Even then, Tim has only seen aliens with eyes like that. The green seemed to draw Tim in, like a moth to flame - unlike a moth, however, Tim had the intelligence to know fire burned.
He glanced back the way he'd been staring at another whistle, but it wasn't one he recognized through trial and error as a call of danger. "Batman doesn't appreciate having metas in Gotham, particularly ones with such... distinct fashion." Tim gave the man a once over, clearly indicating the superhero-esque uniform the other wore.
"Ah, well, good thing I'm not a meta, then." The other shrugged, lounging backwards with his arms propped as if he were sitting cross-legged on the ground instead of the air, with his hands holding him up. "Can't do anything about my fashion choices, though, unfortunately." There was a bitter amusement written across the alien's(?) face, before it faded back into curiosity, "you didn't answer my question. What do the whistles mean?"
Tim... paused. Looked the probable alien over again. He felt he was rather attuned whenever someone was hostile, after everything he'd been through, and the other radiated a simple and almost innocent curiosity. Maybe that was why he found himself muttering, "I don't know," instead of a rebuttal.