One of the new features in World of Warcraft: Legion is the addition of "micro-holidays", events that offer a fun new event for players to participate in. The Hatching of the Hippogryphs event is taking flight on February 23rd and will take place in Feralas. Participants lucky enough to view the "yearly hatching of the hippogryphs" might even get a "little friend for the day".
You can learn more about other micro-holidays and when they take place, by visiting the World of Warcraft community site.
Thanks, Dragnelus!