Aaratica

ability score increase: Choose one of: (a) Choose any +2; choose any other +1 (b) Choose three different +1

age: Aaratica reach maturity by age 3. Compared to humans, aarakocra don't usually live longer than 30 years.

Size: Small

speed: 30 ft, swim equal to your walking speed

Languages: You can speak, read, and write Common and one other language that you and your DM agree is appropriate for your character.

race features:
Beak. Your beak is a natural weapon, which you can use to make unarmed strikes. If you hit with it, you deal piercing damage equal to 1d6 + your Strength modifier, instead of the bludgeoning damage normal for an unarmed strike. Cold-Water Swimmer. You have a swimming speed equal to your walking speed, and you can hold your breath for up to 15 minutes. Icy Terrain Adept. You are naturally adapted to cold climates, as described in chapter 5 of the Dungeon Master's Guide, can cross icy surfaces without needing to make an ability check. Additionally, difficult terrain composed of snow or ice doesn't cost extra movement for you. Tobogganing. When moving across a flat or downward sloping icy surface, you can take the Dash action as a bonus action to slide across the ice on your belly.

The Aaratica, otherwise known as the Aarakocra (Penguin), are a flightless variant of birdfolk with bodies built for swimming rather than flight. Specifically, in swimming through cold waters and climates.