Birdo is a surprisingly heavyweight bruiser character who has poor base mobility, but some great options for getting where she needs to be with her specials. A Birdo player will need to choose wisely where they go and how they get there.
B: Egg Spit
Birdo spits an egg out her mouth - this is a powerful projectile that goes right through foes. Birdo cannot herself be hit by this, even if reflected, and can stand atop it. She can have two eggs out at a time, and the speed of the egg is determined by how long the button is pressed for.
Side B: Suction Kiss
Birdo does a Kirby-esque inhale, being propelled backwards by the force - if she goes off a platform she will start to fly. There's a windbox a little far from Birdo that will slowly draw foes near, and a grabbox closer to her nose/mouth, that when you're hit by she will kiss you then throw backwards.
Up B: Egg Hop
Birdo retreats into an egg and squashes down to charge up a jump. This move doesn't attack, but goes high when charged and has a limited super armour - though the shell can crack with too much damage. The shell also cracks once the egg reaches peak trajectory. This move doesn't leave Birdo helpless, even if the egg is cracked. It can't be cancelled until the hatch expect for one way - if you press any buttom during the jump portion, you will go into Birdo's Down B...
Down B: Pirouette Drill
Birdo gets out a ribbon and performs a pitouette downwards and goes through any soft platforms. If she goes down a soft platform, damaging stars will linger on that platform. This move can be cancelled at any point, but leaves her helpless. This is a multihit attack.