#you might much more readily recognise Tsurubami's ability as “raising poultry” and not “cultivating poultry”

[singular-yike]

Don't know if you already covered this somewhere, but do you have any theories or info for why characters with bird names are seen as either important or people that other characters try to keep a close eye on?

Why no I haven't! There's not much we have right now, not at all, but here's what we do have on Bird's Names.

Canon Mentions

We actually have so little on them, that rather than summarise what we know right off the bat, I think it'd be helpful to show directly what we do have:

RMI Slaver Team - Ex Stage

Tenkai Zuifeng "Since you [Kuroji] bear a "bird's name", it must surely be no coincidence that you came to this world. Was it by Tsurubami's whim, or perhaps by Mugenri's will…?"

BPoHC Shrine Team - Neutral vs. Tenkai Zuifeng

Tsubakura Enraku "So, what exactly are you doing here [Devanagara]?" Tenkai Zuifeng "Birdwatching. [...] I'm here to observe the capital's new emperor." Tsubakura Enraku "The emperor? That counts as birdwatching?" Tenkai Zuifeng "Yes. 'Birds' are those that soar through the heavens, after all. They naturally stand above the rest of the populace."

BPoHC Scoundrel Team - Neutral vs. Tenkai Zuifeng

Hooaka Shitodo "We're all named after birds too, starting with our surnames." Tenkai Zuifeng "You seem to have become accustomed to this place. You may even be able to spread your wings soon enough."

Interview with JynX (2017) Q.50

Q: Medias is a penguin, but why don't they have a Bird's Name? A: They're not a bird that can fly, so they're not as special as the other birds in the cast. A bird's a bird, though, so they're a little special… maybe?

Interpretation

The key thing that makes these "birds" so crucial would seem to be their potential to "rise above" other people, being somehow above them, perhaps in terms of authority, power, or otherwise.

Tying into the above is the fact that it seems that flying birds are given much higher praise than flightless ones, almost certainly to keep in line with the "fly high above the common rabble" theme.

Curiously, you may note that the only in-universe source we have on the concept is Tenkai Zuifeng, a close cooperator of the Senri Shrine. Additionally, they seem to closely guard the secrets of the names, giving only vague hints and metaphors as to what it may mean or represent.

Tenkai is also the only one really keeping tabs on these people, as far as we know. This is in part because they seem to be the only person who knows about the concept, and in part because they're constantly on surveillance for any potential threats to Mugenri, likely a habit from their previous capacity as co-dictator of Mugenri.

Theory: Birds of Potential

This is a very widespread theory that's basically taken as fact these days, I think. And while I do think that it's a very likely interpretation, it should be made clear that it's not outright confirmed.

The names are often interpreted along with Tsurubami's ability to "cultivate poultry", which we know is a metaphor for "releasing and cultivate the latent potential" in certain people.

Combined with the fact that the ability doesn't work on people lacking in potential, and that everyone in EE were holders of bird's names, it's not hard to see how people would come to tie the two facts together.

Under this view, bird's names are basically symbols of having great potential, which does seem to be true, looking at the characters known to have bird's names so far.

However, it should be noted that Tsurubami's power theoretically works on anybody, as long as they have sufficient potential. Additionally, though this is just my opinion, I would imagine that potential is not all these names are about, and that there's more we aren't privy to.

Other Curiosities

A possible hint as to what else these names may mean, is the idea that they are seemingly somehow intrinsically linked to Mugenri.

Tenkai suggests that it might actually be Mugenri's will that all the EE outsiders, every single one of them holders of bird's names, have been spirited away into the mysterious land.

They also seem to suggest that once a person has sufficiently familiarised themself with Mugenri, they'll be able to "spread their wings", likely in a metaphorical sense.

I would imagine that this is not directly about their potential, since the EE outsiders' were already unlocked during EE, but about something else somehow tied to the land they find themself in.

And that's all I have on Bird's Names, still a very mysterious concept, that we aren't really familiar with yet. Nevertheless, we have what we have, and we've made the best use of it.

As usual, I hope you enjoyed~! :)