Trainers, a new Nearby Pokémon Alerts feature has been added to the revamped Pokédex! Trainers can now set an alert for whenever a Pokémon they look after appears on the Nearby screen, similar to how the “New Pokémon spotted” alert works for Pokémon you haven’t caught before.
The system is accessible from the Pokémon screen on the new Pokédex, and it works for almost all Pokémon species. You can only have 1 alert at a time, so choose wisely:
The Pokémon Alerts system also influences how Pokémon appear on your Nearby screen, with tracked Pokémon appearing higher in the list:

The new Alerts system works for most Pokémon, but it doesn’t work for form-changing Pokémon like Ditto or Zorua. This is expected, but we wanted to confirm never the less. You cannot enable alerts for these Pokémon at all.
Strategies for the new Pokédex Alerts
The new Pokédex Alerts system opens up the floor for a few interesting strategies. For example, you could setup an alert for Unown, the Lake Trio Pokémon (Azelf, Uxie, Mesprit), Wiglett, or Dreepy. Or the usual crop of rare Pokémon, like Beldum, Swinub, or Larvitar.
If you are traveling, be sure to setup and alert for the Regional Pokémon! You can see the full list of Regional Pokémon here: Pokémon GO Regional Pokémon List
Or you could setup an alert for a particular Pokémon whose Shiny form you are looking for, especially during events, when Shiny odds can be boosted. For example, during the upcoming Festival of Colors 2025, Bruxish will be debuting as a Shiny, both in Incense and Wild encounters. You can use the new Alerts to be sure not to miss any!