I know this is just a news story and news stories are notorious for being misleading, but I have to ask why these newly-discovered fossils are called "missing links" in bird evolution.
The article says this fossilized species is similar to loons, grebes, and diving ducks which are all modern birds. The fossil is classified in the family Ornithurae which are modern birds. In other words, this happens to be the oldest known specimen of modern birds. That only makes it an evolutionary link if one assumes that all modern birds descended from the oldest known specimen, an assumption which is little more than a speculation based upon a hope.
Moreover, Gansus yumenensis is said to be an evolutionary link not with some other kind of creature but with other birds, ancient birds. It may well be, of course, but to call it a missing link suggests that it has some sort of dinosaur-to-bird evolutionary significance which it clearly does not have.
In other words, the discovery of these fossils doesn't seem to be at all what the news reports imply, but that's not news either.