What do fire rings do?

The fire ring can be found as an orangey-yellow ring of fire, and firing a bird through it will turn the ring Smokey black. The ring gives the bird fired through it explosive power (similar to Bomb’s power). Unlike Bomb’s power, this cannot be used by tapping the screen, and will only be used once the bird has come into contact with obstacles, pigs, other birds or the map itself. If the Blues are fired through the ring while unsplit, all three will retain explosive properties when split.