‘Pokemon Go’ is available for iOS and Android devices. (Niantic)

A new nest migration is about to take place in Pokemon Go.

In the free-to-play mobile games from Niantic Labs, a “nest” is an area of the real world where the same species of Pokemon spawns at a very high frequency and can consistently be found. However, in order to keep things fresh, the game is always changing up what creatures spawn from individual nests.

Specifically, this “migration” takes place every two weeks. Unlike the game updates, which generally occur every two weeks but which do not get released very consistently, the nest migrations pretty reliably happen on every other Thursday.

Therefore, the next Pokemon Go nest migration is expected to occur on Thursday, March 23rd.

Here’s a look at all of the dates on which nest migrations have taken place over the past few months:

  • Migration #16: March 9th
  • Migration #15: February 23rd
  • Migration #14: February 16th
  • Migration #13: February 9th
  • Migration #12: January 26th
  • Migration #11: January 12th
  • Migration #10: December 29th
  • Migration #9: December 15th
  • Migration #8: December 1st
  • Migration #7: November 17th
  • Migration #6: November 3rd
  • Migration #5: October 20th
  • Migration #4: October 6th
  • Migration #3: September 26th
  • Migration #2: August 23rd
  • Migration #1: July 29th

Tomorrow will be the 17th such nest migration to take place since the game was released in July 2016.

This upcoming nest migration will take place following the launch of a special “water festival” event in Pokemon Go; for the next week, water Pokemon will spawn at a higher frequency than usual.