Pokémon Sleep has announced that Rufflet and Braviary will be added to the game starting on January 20th, 2025.

New Arrivals: Rufflet and Braviary

There have been reports of Rufflet and Braviary appearing near certain areas—maybe this is thanks to the sleep research you’ve all been conducting! It may be possible to encounter them during sleep research sometime soon.

New Arrivals:
• Rufflet (Flying)
• Braviary (Flying)

We hope you’re looking forward to this!

Newly Arriving Pokémon Details

Appearing Beginning: January 20, 2025, at 3:00 p.m.
Note: Pokémon Incense for the new arrivals can be used starting from the date and time above.

Appearing at: Greengrass Isle, Cyan Beach, and Snowdrop Tundra
Sleep Types: Rufflet: Slumbering. Braviary: Slumbering
Main Skill: Berry Burst - Gets a set amount of Berries plus a few of each of the Berries other Pokémon on your team collect.
Note: The number of Berries you’ll get is different than what you get from Disguise (Berry Burst).

Source: https://www.pokemonsleep.net/en/news/323233353635363332373738353334393133/