Is Dreamtail Heron legal in Standard, Modern, and Commander?

Dreamtail Heron is legal in: Modern, Pioneer, Legacy, Vintage, Commander, Pauper, Historic.

Dreamtail Heron

Q: What type of card is Dreamtail Heron?

Dreamtail Heron is a Creature — Elemental Bird. Its oracle text reads: "Mutate {3}{U} (If you cast this spell for its mutate cost, put it over or under target non-Human creature you own. They mutate into the creature on top plus all abilities from under it.) Flying Whenever this creature mutates, draw a card. Power/Toughness: 3/4"

Creature — Elemental Bird

Mutate (If you cast this spell for its mutate cost, put it over or under target non-Human creature you own. They mutate into the creature on top plus all abilities from under it.)