The Bird’s Opening is the 6th most popular opening and is a very aggressive opening. White starts out weaking his king side and starts a flank attack on the center with his f pawn. This opening is not used in lots of top level play but some of the most beautiful games in chess history have been played using the Bird’s Opening.
After black defends with d5 the game will transpose into a reverse of the Dutch defense, where white opens with d4 and black responds with f5. White’s main focus is on the dark squares in the game which is a big difference than the usual light squares that white usually focuses on.
While the light square bishop is usually the key minor piece for white, in this opening the dark square bishop actually gets the nod. White will usually fianchetto his bishop on the queen side to b2 and add more pressure on the dark squares.