There's nothing to be confirmed, and there's nothing that can be cancelled. Both terms imply that something is rumoured or in the works. There is nothing. No hints, no rumours, no teasers, no leaks. Since November 2019 "we want birds" has been the national anthem of the PZ community. They aren't coming.
The "bird delusion" is getting a bit ridiculous now. Since the WTE was added to the game, we have had two bats, five butterflies, a sloth, and no birds. We're never getting flying birds in this version of the game. Pray for a sequel in 5-10 years time; that's where they'll probably show up. Let it go already.
Not yet bro, let the illusion be at least for the final of the game. Luckily the support for the game extends a bit more, and we may have a possibility of seeing them.
I remember everyone said the exact same thing about the JWE pteranodons. "They aren't coming", "Wait for the sequel", etc. And finally, bam, pteranodons for the final dlc. Yeah, i know they are different games, but you understood my point. There's no literal point to say "They aren't coming". There isn't enough thing to say that. It's normal to say "At this point, there are less possibilities of having them", or things similar, but never 0%. Of course. it may be already 4 years of the game support, and the possibilities are less, but that's the thing, they're never 0.
Of course is difficult to have them in the 1st game (If at one point a sequel exists), but is not impossible. Is just the illusion of seeing a very requested feature in the game by some people, including myself.