One more thing to note is, the ice version of this card, Snow Bird, does 295-355 ice damage. Also, the accuracy is the same amount for both of these cards (75%).
Does the storm bird TC have a variable damage amount in game? It's more likely that the wiki is unreliable than the description in game is off.
While you are right about the wiki being unreliable, this time they are seemingly right. I say "seemingly" because who could truly know the damage percentage accurately? I've been using this card a few times in the deckathalon events and this is how/when I noticed it.
The card is sold at bazaar and anyone can try it, then report back here of their findings. Buy a few storm bird tc and test it out and report here the different damages it does (with no extra boosts).