If you're not hip to the whole Ark scene, here's a quick catch-up: the latest patch to the dino survival game included some pretty drastic changes to flying dinosaurs, and many players aren't too happy about it. In particular, the winged dinos' flying speed was greatly reduced and capped. There were also reductions to stamina and carry weight. Birds got nerfed, in other words.
For example, my own personal Argy—Argentavis, basically an enormous eagle I can ride—had its pre-patch speed leveled up to about 250%, meaning it was a swift beast to get around on. Post-patch, its speed is not only reduced to 100%, but capped there. The big bird, now none-too-fast, won't ever get any faster, even upon leveling it up. (Note: those points I put into speed have been refunded, and I can use them for other attributes.)
This is going to be a real adjustment for me, and all I use my flyers for is transport: many of those who take great pains to breed their birds into powerful super-beasts are now staring glumly at a stable of greatly lessened creatures. Flying dinos are also a major factor on PvP servers (I don't play PvP), so entire tribe wars are going to have to be rethought.
Well, there's a beacon of hope for those of you who are miserable with the nerfs and don't want to wait to see if they get recalculated in your favor (which they probably will, somewhat). The Classic Flyers mod claims to undo the patch completely. Quoth the mod page:
"Brings back the classic flyers we've all known and loved! This mod gives flyer species back all of their pre-nerf'd stats. Yes, that means they can level speed again."
The mod has some instructions you should read before installing, and it sounds like there may be a few bugs here and there: read all about it, and happy flying.