It means that like-minded people will tend to congregate. It also means you shouldn't mess with birds, because then you've got a whole world of hurt coming down on you. And that's what's happening with the Feather Clan for Crystal Clans. In this preview, we get a look at some of the units they're going to be getting and how they work together.
From the post:
Welcome back to another Crystal Clans preview! We're in our last week of previews for Shadow, Fang, Feather and Leaf! Remember, all four clans are currently available for preorder and you can check out all the previews here! Today, we'll be taking a look at the remaining units for Feather Clan. Previously, being a Flying unit meant that it possessed the ability of Flight or Soar. The Feather Clan brings another neat trick for “flying” across the battlefield!